Wednesday, July 31, 2013

Role of Left Ventricular Diastolic Dysfunction in Predicting Atrial Fibrillation Recurrence after Successful Electrical Cardioversion

Citation : Rowlens M. Melduni, Michael W. Cullen

The role of left ventricular (LV) diastolic dysfunction in predicting atrial fibrillation (AF) recurrence after successful electrical cardioversion is largely unknown. Studies suggest that there may be a link between abnormal LV compliance and the initial development, and recurrence of AF after electrical cardioversion. Although direct-current cardioversion (DCCV) is a well-established and highly effective method to convert AF to sinus rhythm, it offers little else beyond immediate rate control because it does not address the underlying cause of AF. Preservation of sinus rhythm after successful cardioversion still remains a challenge for clinicians. Despite the use of antiarrhythmic drugs and serial cardioversions, the rate of AF recurrence remains high in the first year. Current evidence suggests that diastolic dysfunction, which is associated with atrial volume and pressure overload, may be a mechanism underlying the perpetuating cycle of AF recurrence following successful electrical cardioversion. Diastolic dysfunction is considered to be a defect in the ability of the myofibrils, which have shortened against a load in systole to eject blood into the high-pressure aorta, to rapidly or completely return to their resting length. Consequently, LV filling is impaired and the non-compliant left ventricle is unable to fill at low pressures. As a result, left atrial and pulmonary vein pressure rises, and electrical and structural remodeling of the atrial myocardium ensues, creating a vulnerable substrate for AF. In this article, we review the current evidence highlighting the association of LV diastolic dysfunction with AF recurrence after successful electrical cardioversion and provide an approach to the management of LV diastolic dysfunction to prevent AF recurrence.

Co-existence of Atrial Fibrillation with Myocardial Infarction - Unhealthy Combination

Citation : Maciej Wojcik

Atrial fibrillation (AF) is the most common arrhythmia with increasing prevalence and incidence. As our population ages, modern treatment options and decreased case-fatality of cardiovascular diseases are likely to increase the number of patients at risk for AF. AF is a frequent co-existing complication ofmyocardial infarction (MI). The onset of AF in the setting of AMI requires immediate intervention which should be individualized for each patient. AF associated with MI influences the in-hospital, medium- and long-term mortality. This brief review, based on 41 reports published between 1970 and 2011, focuses on incidence and mortality in patients with AF in MI setting. Possible mechanisms of AF in MI and treatment options are also discussed.

Atrial Remodelling : Role in Atrial Fibrillation Ablation

Citation : Herko Grubitzsch, Wilhelm Haverkamp

There have been considerable advances in understanding the relationship of atrial fibrillation (AF) and atrial remodelling suggesting that remodelling states have a significant impact on treatment results.

Therefore, we reviewed the literature about the role of atrial remodelling in AF treatment, focussing on AF ablation.

Atrial fibrillatory activity, dominant frequencies (DF), complex fractionated atrial electrograms (CFAE) as well as function, volume, and fibrosis of the – especially left – atrium are most important characteristics for electrical, contractile, and structural remodelling predicting success of AF treatment. In particular, the results of AF ablation, either using catheter-based or surgical techniques, predominantly depend on the degree of structural remodelling, namely dilatation and fibrosis of the left atrium.

The available data suggest that recognizing parameters of remodelling as predictors for AF treatment facilitates differentiation between patients who may or may not benefit from the procedure and individualization of AF treatment by adapting lesion sets, by ablating additional targets, by reducing left atrial size, or by applying extended pharmacological treatment.

Omega-3 Polyunsaturated Fatty Acid Supplementation: Mechanism and Current Evidence in Atrial Fibrillation

Citation : Savina Nodari, Marco Triggiani, Umberto Campia, Livio Dei Cas

Atrial fibrillation (AF) is the most prevalent arrhythmia and is associated with considerable morbidity and mortality. Available pharmacologic antiarrhythmic therapies are often ineffective in preventing the recurrence of AF, possibly because these drugs target a single pathophysiological mechanism. Given their beneficial effects on ventricular arrhythmias, omega-3 polyunsaturated fatty acids (n-3 PUFAs) have recently been investigated as possible candidates in the treatment of supraventricular arrhythmias. In this review, we explore the current understanding of the antiarrhythmic effects attributed to n-3 PUFAs including direct modulation of ionic channels, improvement of membrane fluidity, anti-inflammatory and antifibrotic effects, and modulation of sympatho-vagal balance. We will then focus on the results of epidemiologic studies exploring the associations between nutritional intake of n3 PUFAs and the incidence of AF, and will review the findings of the clinical trials investigating the effects of n-3 PUFAs supplementation in the prophylaxis of AF and in the prevention of its recurrences.

Impact of Atrial Fibrillation On Cardiovascular Mortality in the Setting of Myocardial Infarction

Citation : Mahmoud Suleiman, Doron Aronson

Atrial fibrillation (AF) commonly occurs in patient with acute myocardial infarction (AMI). Potential triggers for AF development in this setting includes reduced left ventricular function, advanced diastolic dysfunction and mitral regurgitation leading to elevated left atrial pressures and atrial stretch. Other triggering mechanisms include inflammation and atrial ischemia. Multiple studies have shown that AF in patients with is associated with increased mortality. However, whether AF is a risk marker or a causal mediator of death remains controversial.

There is relative dearth of data with regard to optimal management of AF in the setting of acute coronary syndromes. Patients with AMI who develop AF are at increased risk of stroke. However, the issue of the most appropriate antithrombotic regimens is complex given the need to balance stroke prevention against recurrent coronary events or stent thrombosis and the risk of bleeding. Presently, ‘triple therapy’ consisting of dual antiplatelet agents plus oral anticoagulants for 3–6 months or longer has been recommended for patients at moderate–high risk of stroke.

Atrial fibrillation (AF), the most common sustained arrhythmia seen in clinical practice, often coincides with acute myocardial infarction (AMI), with a reported incidence ranging between 7% and 21%.1 The development of atrial fibrillation in the acute phase of AMI may aggravate ischemia and heart failure, lead to clinical instability and adversely affect outcome. In the following we will review the pathophysiology, clinical characteristics and importance, and management of AF occurring in the setting of AMI.

Tuesday, July 30, 2013

Operative Technique and Atrial Tachyarrhythmias After Orthotopic Heart Transplantation

Citation : Srinivasan Sattiraju, Shashank Vats, Balaji Krishnan, Sun K. Kim, Erin Austin, Ilknur Can, Venkatakrishna Tholakanahalli, David G. Benditt, Lin Y. Chen

There is conflicting evidence that operative technique affects the risk of atrial tachyarrhythmia after orthotopic heart transplantation (OHT). We sought to determine whether OHT by bicaval (BC) technique is associated with a lower risk of atrial tachyarrhythmia than biatrial (BA) technique. Consecutive patients who underwent OHT between 1997 and 2007 at the University of Minnesota were included in this retrospective cohort study with follow-up through December 31, 2011. We included 260 OHT recipients (BA, 155; BC, 105). Fifty-nine patients (22.7%) developed early atrial tachyarrhythmias. The multivariable odds ratio (95% confidence interval [CI]) of BC technique for early atrial tachyarrhythmias was 0.85 (0.46-1.57), P=0.59. After a median follow-up of 4.9 years, 40 (15.4%) patients developed late atrial tachyarrhythmias. The multivariable hazard ratio (HR) (95% CI) of BC technique for late atrial tachyarrhythmias was 0.99 (0.50-1.96), P=0.98. Graft rejection was found to be a multivariate predictor of late atrial tachyarrhythmias (HR, 2.89; 95% CI, 1.48-5.65; P=0.002). In contrast to prior reports, we did not find an association between operative technique and early or late atrial tachyarrhythmias after OHT. Graft rejection is a risk factor for late atrial tachyarrhythmias after OHT.

The 894G Allele of the Endothelial Nitric Oxide Synthase 3 (eNOS) is Associated with Atrial Fibrillation in Chronic Systolic Heart Failure

Citation : Fuad Fares, Yoav Smith, Naiel Azzama, Barak Zafrir, Basil S. Lewis, Offer Amir

Background: Atrial fibrillation (AF) in patients with heart failure signals poor prognosis. The endothelial nitric oxide synthase (eNOS) enzyme is a key player in the counterregulation of oxidative stress, which is related in part to AF pathogenesis. The purpose of this study was to investigate a possible clinical association in heart failure patients between the presence of exon 7 G894T eNOS polymorphism, known to result in the Glu298Asp protein variant, and the occurrence of AF.

Methods: We analyzed the DNA of 344 patients with chronic systolic heart failure for exon 7 G894T eNOS polymorphism, using PCR. Odds ratios for AF were calculated for the homo- and heterozygous G-allele G894T variants relative to the TT variant.

Results: Of the 344 patients, 204 (59%) were homozygous for the G allele, 122 (36%) were heterozygous (GT), and 18 (5%) were homozygous for the T allele. AF episodes were documented in 73 patients (36%) with the GG genotype, in 35 (29%) with GT, and in 2 (11%) with TT. The odds ratio for AF, based on the presence of at least one G allele in the eNOS 894 gene, was 3.96 (95% confidence interval, 1.17‒13.56, p=0.04). Having two G alleles increased the odds ratio to 4.5 (95% confidence interval, 1.0‒20.0, p=0.02).

Conclusion: Patients with systolic heart failure demonstrate strong correlation between AF and the presence of a G allele in the exon 7 G894T eNOS genotype. These findings support the importance of eNOS polymorphism in the pathogenesis of AF in heart failure patients.

Sarcoidosis Masquerading as Atrial Fibrillation: Interesting Case Discussion as Well as Recent Advances in Diagnosis and Management of Cardiac Sarcoidosis

Citation : Jefferson Curimbaba, João Pimenta, José Marcos Moreira, UlSilvia Carla Sousa Rodrigues,  Ester Nei Aparecida Coletta, Carlos A.C. Pereira

This report presents a case of cardiac sarcoidosis initially manifested with atrial fibrillation. This behavior is very uncommon in spite of the fact that the disease is multisystemic, affecting predominantly the lungs. It is emphasized that the diagnosis of the cardiac involvement is difficult, and when this occurs, can lead to conducting system disturbances, heart failure or sudden death (SD). The diagnosis can be made by evaluating the clinical manifestations, the noninvasive tests like ECG, Holter monitoring, chest radiography, thoracic computed tomography, magnetic resonance image and positron emission tomography. In general, sarcoidosis is treated with steroid compounds with good outcome, mainly when performed in the initial phases of the disease. Other cardiac manifestations, such as arrhythmias, atrioventricular block or heart failure, are managed similar to other cardiomyopathies.

Reversal of Dilated Cardiomyopathy After Successful Radio-Frequency Ablation of Frequent Atrial Premature Beats, a New Cause for Arrthyhmia-Induced Cardiomyopathy

Citation : Paul Louis Vervueren, Clement Delmas, Mathieu Berry, Anne Rollin, Marie Sadron, Alexandre Duparc, Pierre Mondoly, Benjamin Honton, Olivier Lairez, Philippe Maury

Incessant atrial premature beats as a potential cause for tachycardia-induced cardiomyopathy was suspected in a patient presenting with dilated non-ischemic cardiomyopathy and severely altered left ventricular ejection fraction. The elimination of a left atrial focus by percutaneous RF ablation led to normalization of the clinical status, of atrial and ventricular dimensions and left ventricular systolic function.

Subclinical Hypothyroidism: An Overlooked Cause of Atrial Fibrillation?

Citation :  Theofilos M. Kolettis, Agathocles Tsatsoulis

The association between clinical1 or subclinical2 hyperthyroidism and atrial fibrillation is established from large prospective cohort studies, with serum free thyroxin (T4) concentrations correlating with atrial fibrillation rates.3 However, the role of subclinical hypothyroidism as a causal factor for atrial fibrillation has not been elucidated.

Recently, we have had under our care two patients with episodes of paroxysmal or persistent atrial fibrillation and absence of identifiable causes, other than subclinical hypothyroidism.

Thursday, July 25, 2013

New Stroke Prophylaxis Options in Atrial Fibrillation Patients

Citation : George Thomas, Bruce B Lerman

Atrial Fibrillation (AF) is an epidemic that is increasing in size and scope.  AF can have many symptoms and cause a variety of negative health impacts.The most important health risk of AF is the increased risk of stroke and systemic thromboembolism.Oral anticoagulation with warfarin has been the gold standard for stroke risk reduction in AF, but new drugs and treatment strategies for AF are changing clinical practice.  These new advances could offer better tailoring of treatments to patients with high risk of stroke while reducing the potential bleeding complications.

Atrial Fibrillation in Patients with Ischemic and Non-Ischemic Left Ventricular Dysfunction

Citation : Robin Ducas, Vignendra Ariyarajah

Atrial fibrillation (AF) and left ventricular dysfunction (LVD) are increasingly common clinical problems, affecting millions of people worldwide. It is well established that the presence of AF portends a poor prognosis in the setting of both ischemic and non-ischemic LVD, and frequently results in worsening clinical status. Many clinical studies and trials have attempted to address treatment options and efficacy; despite this treatment for AF in LVD is still controversial.

Wednesday, July 24, 2013

Primary Prevention of Atrial Fibrillation – The Path Untread

Citation : Joel A. Lardizabal, Prakash C. Deedwania

The prevalence and incidence of atrial fibrillation (AF) is on the rapid rise. To slow down the AF epidemic, effective primary prevention strategies need to be instituted. Unfortunately, this is an area that has not been well-explored. There is a multitude of risk factors that predispose to the development of AF. Of these, the most common from an epidemiologic perspective are advanced age, hypertension, diabetes, ischemic heart disease, and heart failure. The first-line pharmacologic therapies for these predisposing conditions (e.g. beta blockers, renin-angiotensin system inhibitors, statins, and omega-3 fatty acids) appear to also have potential roles in the primary prevention of AF. Definitive data, however, is lacking as to efficacy of these drugs for this particular purpose. Large-scale, high-quality randomized clinical trials on AF primary preventive strategies are urgently required in order to guide clinical practice. For now, adherence to the guideline-based therapies of each individual risk factor appears to be the most reasonable approach for the primary prevention of AF.

Is An Atrial Defibrillator Still An Option In Treating Patients With Atrial Fibrillation?

Citation : Ziad El Khoury, Deepak Bhakta

Atrial fibrillation (AF) is a common disorder associated with significant morbidities and presents several challenges for the control of symptoms and prevention of long-term implications. Atrial defibrillators (ADs), used for rhythm control in patients with symptoms refractory to medical therapy, can detect recurrences of the arrhythmia, allow prompt patient-directed treatment, and have the potential to reduce hospitalizations and improve quality of life. The efficacy of this form of therapy is highest in patients with paroxysmal AF, and with the use of a coronary sinus shocking lead. While R-wave synchronized shocks are a prerequisite for a safe use, the procedure is well tolerated and usually not associated with long-term psychological side effects. Limitations of ADs include acute and chronic complications related to cardiac rhythm device implantation, the requirement in some cases for more than one shock to terminate AF, the discomfort from shocks, as well as the need for sedation to alleviate pain from the shocks. With the ever-expanding role of catheter-based therapies for AF, it seems that the role of ADs in this regard is rather limited.

Prophylactic Antiarrhythmic Drug Therapy in Atrial Fibrillation

Citation : Moisés Rodríguez-Mañero, Andrea Sarkozy, Gian-Battista Chierchia, Rubén Casado-Arroyo, Danilo Ricciardi, Carlo de Asmundis and Pedro Brugada

In patients with recurrent atrial fibrillation (AF), the hallmark of treatment has been the use of antiarrhythmic drugs (AADs). Goals of therapy include reduction in the frequency and duration of episodes of arrhythmia as well an emerging goal of reducing mortality and hospitalizations associated with AF. Safety and efficacy are important factors when choosing an antiarrhythmic drug for the treatment of AF, hence, if AAD are required for maintenance of sinus rhythm, their safety profi le, together with individual patient characteristics, should be of utmost concern. In the next paragraphs we would like to review some aspects (electrophysiologic effects, metabolism, side effects, current evidence and indication) of the most commonly used AAD for the management of patients with AF, following the Vaughan-Williams classification. However, this system is mainly based on ventricular activity, therefore, and due to its relatively atrial selective actions, some agents will not readily fit in the Vaughan Williams AAD classification. For that reason, in the final part of the manuscript, new promising agents will be reviewed separately.

The Relationship Between Pericardial Fat and Atrial Fibrillation

Citation : Myung-jin Cha, Seil Oh

Pericardial adiposity is strongly associated with increased cardiovascular risk, especially for coronary artery disease. However, until 2010 researchers have not focused on the mechanistic role of pericardial fat in atrial fibrillation (AF) pathogenesis. Only a limited number of studies have reported on the significant association between pericardial fat and AF prevalence, and the role of pericardial fat on AF chronicity and symptom burden remain an ongoing debate. Several possible mechanisms associating pericardial fat with increased AF prevalence have been suggested, but no prior studies have definitively elucidated the precise role of pericardial adiposity on increased AF risk. Currently, pericardial fat has recently emerged as a new independent AF risk factor. In this brief review, we discuss several potential mechanisms that might associate pericardial fat to AF pathogenesis.

Catheter Ablation of Long Standing Persistent Atrial Fibrillation: Lessons Learned

Citation : Obiora Anusionwu, Hugh Calkins

Atrial fibrillation has evolved from being a novel unproven procedure to being an important treatment option for patients with symptomatic atrial fibrillation. Atrial fibrillation ablation is an appropriate treatment option for patients with symptomatic atrial fibrillation, particularly if they have failed one or more trials of antiarrhythmic drug therapy. While much has been learned about the optimal technique and outcomes for catheter ablation of paroxysmal atrial fibrillation; catheter ablation of atrial fibrillation in patients with long standing persistent atrial fibrillation remains in its infancy. The following objectives would be accomplished in this review article.

First, we will review the various ablation strategies, which have been employed and proposed for ablation of long standing persistent atrial fibrillation. Second, the methodology, results and outcomes of the major studies were reviewed in detail, which have reported outcomes of ablation in this patient population. And finally, some conclusions were drawn regarding where we stand and where the knowledge gaps remain as we seek to improve ablation outcomes in this population of AF patients.

Tuesday, July 23, 2013

Prevention of Stroke by Antithrombotic Therapy in Patients with Atrial Fibrillation

Citation : Athanasios J. Manolis, Leonidas E. Poulimenos

Atrial Fibrillation (AF) is the most common clinically significant sustained cardiac arrhythmia, a major risk factor for strokes whether it is symptomatic or silent. The older CHADS2 score and the newer CHA2DS2-VASc are well validated to determine stroke risk and guide initiation of antithrombotic therapy, but haemorrhagic risk has to be respected as well, and scores such as HAS-BLED should be widely used. Old fashioned warfarin became standard of care outperforming antiplatelets in every trial but novel classes of anticoagulants that overcome many of warfarin drawbacks have been introduced and are already guideline recommended regiments. Nevertheless their use poses new questions that have to been answered in the near future.

The Temporal Relationship Between Atrial Fibrillation and Ischemic Stroke

Citation : Paul D. Ziegler

It is well established that the presence of atrial fibrillation (AF) is associated with an increased risk of stroke; however, the precise role that AF plays in increasing this risk is less well understood. In particular, it is not fully known whether a temporal relationship between AF and stroke exists. Early clinical trials in this field were limited by their rudimentary tools for monitoring of AF recurrences. More recently, studies employing implantable cardiac rhythm devices have brought greater precision to our ability to accurately detect and quantify episodes of AF but have been restricted to patient populations with clinical indications for those types of devices. In the future, new monitoring modalities such as subcutaneous devices and external patches may allow us to extend precise arrhythmia monitoring to the broader AF population. Due to the relatively low rate of clinical events, large clinical trials or registries will be required to fully appreciate the temporal aspects of AF and stroke and alternative metrics for quantifying AF recurrences need to be explored.

Catheter Ablation of Atrial Fibrillation to Maintain Sinus Rhythm

Citation : Jane Dewire and Hugh Calkins

Catheter ablation of atrial fibrillation (AF) is an important treatment modality for patients with AF. Although the superiority of catheter ablation of AF over antiarrhythmic drug therapy has been demonstrated in middle aged patients with paroxysmal AF, the role of catheter ablation in other patient subgroups, particularly in the elderly, those with heart failure, and those with long standing persistent AF has not been as well defined. Furthermore, although AF ablation can be performed with reasonable efficacy and safety in experienced hands, late recurrences of AF a year or more following AF ablation are not uncommon. Fortunately the techniques and tools used for AF ablation continue to evolve and it is likely that the outcomes of AF ablation will improve further in the future.

Atrial Fibrillation in Patients with Cardiac Resynchronization Therapy: Clinical Management and Outcome

Citation : Giuseppe Boriani, Paola Battistini, Igor Diemberger, Matteo Ziacchi, Cinzia Valzania, Cristian Martignani, Mauro Biffi

Atrial fibrillation (AF) and heart failure (HF) are two emerging epidemics in the cardiovascular field and are strictly inter-related since may directly predispose to each other. Cardiac resynchronization therapy (CRT) has emerged as an important therapeutic option for selected HF patients with LV dysfunction and ventricular dyssynchrony. However almost all RCTs demonstrated the CRT effectiveness in patients in sinus rhythm (SR), including permanent AF among the exclusion criteria.

In patients with paroxysmal or persistent AF strategies for rhythm control can be applied, but usually with limited efficacy. Furthermore, rhythm control strategy did not result superior to rate-control in patients with heart failure. AF ablation in HF patients is usually performed only in selected centres. In patients with permanent or long-standing AF and a CRT device the option of AVN ablation offers the advantage of allowing >95% biventricular pacing.

AF implies a harmful increase in thromboembolic risk. Detection of AF in patients treated with a CRT device is enhanced by device diagnostic capabilities, that allow detection of episodes of atrial tachyarrythmias, including silent AF. In these cases decision making on appropriate antithrombotic prophylaxis has to consider clinical risk stratification, usually applying CHADS2 and CHA2DS2VASc scores.

In summary, in order to maximise outcome, AF in patients with CRT prompts the need to appropriately decide on antithromboembolic prophylaxis (according to risk stratifications), as well as on rate and/or rhythm control strategies, with the aim to allow constant biventricular pacing. In this perspective, AVN ablation has an important role since by inducing pace-maker dependency guarantees continuous biventricular pacing.

Impact of Obstructive Sleep Apnea on Outcomes of Catheter Ablation of Atrial Fibrillation

Citation : Jane Dewire and Hugh Calkins

Obstructive sleep apnea (OSA) is a growing epidemic in the United States and significantly contributes to the increasing prevalence of atrial fibrillation (AF) in the U.S. population. Although a strong correlation between OSA and AF has been demonstrated, a causal relationship between these two conditions has not been definitively established. Evidence of OSA is an important consideration of AF management and impacts the success rate of catheter ablation. The presence of OSA tends to predict a lower success rate and higher complication rate for catheter ablation of AF. However, recent studies evaluating OSA as an independent risk predictor of AF recurrence following an ablation procedure have yielded conflicting results. A greater understanding of these conditions would allow for a more specific therapy targeting the type of AF associated with OSA. The following review provides a brief summary of obstructive sleep apnea etiology, focuses on the relationship between OSA and AF, and discusses the impact of OSA on the outcomes of catheter ablation of AF.

The Role of Pericardial and Epicardial Fat in Atrial Fibrillation Pathophysiology and Ablation Outcomes

Citation : Christopher X. Wong, Rajiv Mahajan, Rajeev Pathak, Darragh J. Twomey, Prashanthan Sanders

Emerging evidence suggests that epicardial and pericardial fat are related to the presence, severity and outcome of AF. These associations, independent of generalized obesity, suggest that they may become increasingly useful as markers for risk stratification or monitoring in the clinical setting. Mechanistically, studies have suggested the effects of epicardial and pericardial fat may be mediated by local adipokines, inflammation, fatty infiltration, modulation of AF drivers and left atrial dilatation. Given the dual epidemics of AF and obesity, in the present paper we review the role that the ectopic adipose tissue surrounding the heart has in the pathogenesis of AF. Further inquiries in this active area of investigation may ultimately lead to new insights in how to best combat these interrelated epidemics and reduce the societal burden of AF.

Impact of Metabolic Syndrome on Ablation-Outcome in Patients with Atrial Fibrillation: A Systematic Review

Citation : Sanghamitra Mohanty, Luigi Di Biase, Prasant Mohanty, Pasquale Santangeli, Bai Rong, Trivedy Chintan, David Burkhardt, Joseph G Gallinghouse, Rodney Horton, Javier E Sanchez,  Shane Bailey, Jason Zagrodzky, Andrea Natale

Metabolic syndrome (MS), a pro-inflammatory state with hypertension, diabetes, dyslipidemia and obesity is presumed to be a close associate of atrial fibrillation (AF). However, the exact mechanism by which MS facilitates perpetuation of AF is yet to be fully understood. Moreover, the impact of the components of MS as well as MS as a group, on ablation-outcome in AF is not clearly elucidated until now. This review has compiled the results from major studies that have looked into those risk factors and defined their significance in influencing ablation-outcome in AF. It has also overviewed the impact of life-style changes that might improve the success rate of AF-ablation by effectively addressing the different constituents of MS.

The Relationship Between Physical Activity and Risk of Atrial Fibrillation-A Systematic Review and Meta-Analysis

Citation : Jens Rokkedal Nielsen, Kristian Wachtell, Jawdat Abdulla

Aim: The aim of this systematic literature review and meta-analyses was to explore the relationship between physical activity and risk of new-onset atrial fibrillation (AF) or flutter (AFlu).

Results: The search revealed 10 published studies that were eligible for three different meta-analyses. A meta-analysis of six case-control studies showed that risk of AF increased more than 5-fold in athletes compared to non-athletic controls, OR=5.3 [(3.6, 7.9; 95% confidence interval (CI)], p<0.0001. A second meta-analysis of three case-control studies showed a significantly higher prevalence of athletes among AF populations compared to their healthy controls, OR=4.7 (3.1-6.9; 95% CI), p<0.0001. A third meta-analysis of three prospective large-scale long-term studies showed that moderate/high habitual physical activity was associated with significantly reduced risk of AF compared with none or very low intensity physical activity OR=0.89(0.83, 0.96; 95% CI), p=002.

Conclusions: Long-term vigorous physical training or lack of physical activity both are associated with increased risk of AF, while habitual moderate physical activity may be associated with reduced risk. Further large-scale prospective randomized controlled studies particularly in athletes are needed to further confirm these findings.

Risk Factors for Post-Coronary Artery Bypass Grafting (CABG) Atrial Fibrillation and the Role of Aspirin and Beta Blockers in its Prevention

Citation : Muhammad F Khan, Aravind Herle, Mohammad Reza Movahed

Background: Atrial fibrillation/flutter (AF) is the most common arrhythmia following coronary artery bypass grafting (CABG) and it increases morbidity and mortality associated with this procedure. The purpose of this study was to evaluate the predictability of this arrhythmia using previously identified risk factors and to assess the efficacy of recommended prophylactic beta blocker (BB) therapy in the prevention of post CABG AF.

Methods: We performed a retrospective chart analysis of consecutive patients undergoing elective CABG during 1 year period. Patients who developed new onset AF after the surgery were designated as cases and those who did not, as controls. 41 different variables were analyzed using Chi-square test and independent sample t-test. Multivariate analysis was carried out using logistic regression model.

Results: 23% patients undergoing CABG developed AF during post-operative period. Statistically significant differences were observed between the two groups in terms of age, use of peri-operative Aspirin (ASA), current smoking, previous history of AF, left atrial size, history of congestive heart failure (CHF) and brain natriuretic peptide (BNP) levels. In terms of prophylactic therapy, preoperative BB did not independently protect against post CABG AF. On multivariate analysis, only age, use of ASA and previous history of AF remained as independent predictors of post CABG AF.

Conclusion: In our study population, the use of preoperative BB did not independently decrease the risk of post-CABGAF. Age, peri-operative ASA use and previous history of AF remained strong independent predictors of post- operative AF.

Amiodarone Induced Thyrotoxicosis – Fluctuating RVOT and LV Scar VT

Citation : Jayasree Pillarisetti, Subba reddy Vanga, Dhanunjaya Lakkireddy

A 61 year old patient with non-ischemic cardiomyopathy and implantable cardioverter defibrillator presented with multiple shocks for ventricular tachycardia (VT). EKG revealed monomorphic sustained VT which was left bundle inferior axis that spontaneously changed into sustained VT which was right bundle superior axis. This was suggestive of an outflow tract VT transforming into a VT probably related to reentry from LV scar. The patient was transferred to our university for VT ablation. However, further investigation revealed amiodarone induced hyperthyroidism which was the cause of his ventricular tachycardia storm. Reversible causes of VT should be considered before proceeding with radiofrequency ablation.

Saturday, July 20, 2013

Catheter Ablation of Atrial Fibrillation in Patients with Hardware in the Heart : Septal Closure Devices, Mechanical Valves and More

Citation: Stefano Bartoletti, Pasquale Santangeli, Luigi DI Biase, MD, Andrea Natale

Patients with mechanical “hardware” in the heart, such as those with mechanical cardiac valves or atrial septal closure devices, represent a population at high risk of developing AF. Catheter ablation of AF in these subjects might represent a challenge, due to the perceived higher risk of complications associated with the presence of intracardiac mechanical devices. Accordingly, such patients were excluded or poorly represented in major trials proving the benefit of catheter ablation for the rhythm-control of AF. However, recent evidence supports the concept that catheter ablation procedures might be equally effective in these patients, without a significant increase in the risk of procedural complications. This review will summarize the current state-of-the-art on catheter ablation of AF in patients with mechanical “hardware” in the heart.

Role of Cardiac Imaging for Catheter-based Left Atrial Appendage Closure

Citation : Sébastien Marchandise, Joëlle Kefer, Jean-Benoît le Polain de Waroux, Christophe Scavée, Jean-Louis Vanoverschelde

Thromboembolic stroke is the most serious complication in patients suffering from Atrial Fibrillation. Atrial thrombi have a predilection to form in the left atrial appendage. Accordingly, oral anticoagulation is recommended for patients with high risk of stroke. However, it is widely underused and problems of compliance are associated with serious risk of bleeding or inefficacy. In these  patients with non-valvular atrial fibrillation, percutaneous occlusion of the left atrial appendage might help to reduce the risk of thromboembolism.

Cardiac imaging plays a crucial role at all stages of this procedure and trans-esophageal echocardiography represents the current goldstandard for the assessment of the left atrial appendage. Cardiac imaging is mandatory to precisely determine the left atrial appendage anatomy and to select the appropriate size for the device. Finally, real time three-dimension echocardiography is a powerful additional tool that improves the safety profile of the procedure. 3D-transoesophageal echocardiography allows for the accurate assessment of left atrial appendage anatomy and helps determine if it’s suitable for device implantation. Finally, it also allows for continuous visualization of all intracardiac devices and catheters during the procedure, and the clear delineation of device positioning in the left atrial appendage.

Surgery for Atrial Fibrillation: Selecting the Procedure for the Patient

Citation : Rui Providência, Sérgio Barra, Carlos Pinto, Luís Paiva, José Nascimento

This manuscript aims to review the current knowledge in the field of surgical ablation of atrial fibrillation (AF), including a brief discussion regarding the standard Maze procedure, its variants, minimally invasive thoracoscopic procedures and hybrid treatments, which briefly summarizes the advantages and differences between each technique. The rationale for the surgical approach of the left atrial appendage, its different techniques and complications will also be briefly covered. To conclude, the current Expert Consensus recommendations will be reviewed and an algorithm for the surgical management of the patient with AF, suggesting which technique applies better to which patient, under specific settings, will also be proposed.

Atrial Fibrillation and Heart Failure: A Review of the Intersection of Two Cardiac Epidemics

Citation : Kay Lee Park, Elad Anter

Atrial fibrillation and heart failure are closely linked cardiac conditions that are both increasing in prevalence due to shared risk factors and common disease mechanisms. The presence of both disease entities portends an increase in morbidity and mortality. There are significant similarities in the treatment strategies of these conditions, and the adequate management of one disease may prevent the development of the other. To this date, a rhythm control strategy, even in the heart failure population, has not been proven to be superior to a rate control strategy. This may in large be due to study design coupled with deleterious effects of antiarrhythmic agents. There have been considerable advances over the past decade in catheter and device based management of atrial fibrillation and studies aimed to examine their long-term effect in patients with heart failure are underway.

Hybrid Therapy for Atrial Fibrillation: Where the Knife Meets the Catheter

Citation : Antonio Curnis, Gianluigi Bisleri, Luca Bontempi, Francesca Salghetti, Manuel Cerini, Alessandro Lipari, Carlo Pagnoni, Francesca Vassanelli, Claudio Muneretto

During the past decades there has been a consistent evolution of both surgical and catheter-based techniques for the treatment of stand-alone atrial fibrillation, as alternatives or in combination with anti-arrhythmic drugs. Transcatheter ablation has significantly improved outcomes, despite often requiring multiple procedures and with limited success rates especially in presence of persistent atrial fibrillation. Surgical procedures have dramatically evolved from the original cut-and-sew Maze operation, allowing nowadays for closed-chest epicardial ablations on the beating heart.

Recently, the concept of a close collaboration between the cardiac surgeon and the electrophysiologist has emerged as an intriguing option in order to overcome the drawbacks and suboptimal results of both techniques; therefore, the hybrid approach has been proposed as a potentially more successful strategy, allowing for a patient-tailored therapeutical approach.

we reviewed the recent advancements either from the transcatheter and surgical standpoint, with a peculiar focus on the current option to merge both techniques along with an up-to-date review of the preliminary clinical experiences with the hybrid, surgical-transcatheter treatment of stand-alone atrial fibrillation.

Age as a Risk Factor for Stroke in Atrial Fibrillation Patients: Implications in Thromboprophylaxis in the Era of Novel Oral Anticoagulants

Citation : Konstantina Mitrousi, Gregory Y H Lip, Stavros Apostolakis

Atrial fibrillation is associated with significant morbidity and mortality. There is a strong relationship between atrial fibrillation and aging, thromboembolism, stroke, congestive heart failure and hypertension. In addition, advanced age is a powerful risk factor for stroke and thromboembolism in patients with atrial fibrillation.

For many years, vitamin K antagonists were the only approved anticoagulants for the management of atrial fibrillation. Lately new anticoagulants made their appearance and large trials have already shown their superiority against vitamin K antagonists. Since the arrhythmia is encountered frequently in the elderly, it is crucial to identify the beneficial effects of the novel oral anticoagulants in this particular patient population.

Thursday, July 18, 2013

Rate Control in Atrial Fibrillation: Methods for Assessment, Targets for Ventricular Rate During AF, and Clinical Relevance for Device Therapy

Citation : Shantanu Sarkar, Paul D. Ziegler

Rate control is a widely used treatment strategy for management of patients with atrial fibrillation (AF). Multiple studies have shown that pharmacologic rate control is as effective as pharmacologic rhythm control for management of AF. A snapshot ECG or intermittent monitoring using Holters is the most widely used technique for assessing ventricular rate during AF. Patients with implantable devices, such as pacemakers, implantable cardioverter defibrillators, cardiac resynchronization therapy devices, and implantable loop recorders provide the ability for continuous long term monitoring of AF and ventricular rate during AF. It has been shown that continuous monitoring of AF and ventricular rate during AF by implantable devices is the most comprehensive method for assessment of AF occurrence and poor rate control, particularly in patients with paroxysmal and asymptomatic AF. Rapid ventricular rate during AF, as assessed by implantable devices, has been shown to cause reduction in cardiac resynchronization therapy, predict inappropriate defibrillation therapy, and identify increased risk for cardiovascular hospitalizations. The ventricular rate targets for achieving good rate control during AF depend on the patient characteristics with stricter targets recommended for patient with compromised functional capacity, such as patients with HF. Thus it can be hypothesized that timely intervention based on continuous assessment of AF and poor rate control, with ventricular rate targets defined based on cardiovascular disease state, may improve clinical outcomes in patients with AF.

Thinking outside the Box: Rotor Modulation in the Treatment of Atrial Fibrillation

Citation: Ruchir Sehra, Sanjiv M. Narayan, John Hummel

Ablation for atrial fibrillation (AF) is an important and exciting therapy whose results remain  suboptimal. Although most clinical trials show that ablation eliminates AF more effectively than medications, it is disappointing that the continued single procedural success remains ≈50% despite the substantial advances that have taken place in imaging, catheter positioning and energy delivery. Focal impulse and rotor modulation (FIRM), on the other hand, offers the opportunity to precisely define and then ablate patient-specific sustaining mechanisms for AF, rather than trying to eliminate all possible AF triggers. For over a decade, electrophysiologists have described cases in which AF terminates after only limited ablation – usually that cannot be explained by ‘random’ meandering wavelets. Indeed, recent studies from several laboratories show that all forms of clinical AF are typically ‘driven’ by stable electrical rotors and focal sources, not by multiple meandering waves. FIRM mapping enables an operator to place a catheter at typically 1-3 predicted sites in the atria, and with <5-10 minutes of RF ablation, terminate AF and potentially render it non-inducible. Several independent laboratories have now shown that such FIRM ablation alone can terminate or  substantially slow AF in >80% of patients with persistent and paroxysmal AF and increase the single procedure rate of AF elimination from 50% with PV isolation alone to >80%. Ongoing studies hint that FIRM only ablation, enabling ablation times in the range observed for typical atrial flutter, may also achieve these high success rates without subsequent trigger ablation. This review summarizes the current state-of-the-art on FIRM mapping and ablation.

Sleep Disordered Breathing and the Pathogenesis of Atrial Fibrillation

Citation : Thomas Bitter, Dieter Horstkotte, Olaf Oldenburg

This review illustrates the importance of sleep disordered breathing in evolution and progression of atrial fibrillation. While in early years associations were mainly attributed to the impact of hypoxemia and hypertension, nowadays multiple, additional pathways have been investigated or are currently under investigation. Sleep disordered breathing has been shown to have a direct impact on  mechanical and electrical remodeling. In addition hypercapnia and negative intrathoracic pressure seem to alter atrial electrophysiology. Finally, impacts on inflammation and metabolic dysregulation display the complex interplay between breathing disorders and evolution and progression of atrial fibrillation.

Pharmacological Therapy in Stroke Prophylaxis : The New versus the Old Agents

Citation : Abhishek Maan, E. Kevin Heist, Jeremy N. Ruskin, Moussa Mansour

Atrial fibrillation (AF) is the most common cardiac arrhythmia encountered in clinical practice. AF is a potent risk factor for stroke and systemic thromboembolism. Patients with AF have been observed to have a worse outcome following stroke, therefore prevention of stroke in patients with AF is of paramount importance. Antithrombotic therapy is crucial for prevention of stroke in patients with AF. Vitamin K antagonists (VKAs) have been the traditional anticoagulants for prevention of stroke in patients with AF. Drug treatment with VKAs is associated with significant management issues, such as an unpredictable dose response necessitating dose adjustments, frequent laboratory monitoring and multiple interactions with other drugs. Despite following best practices, VKAs are associated with limited efficacy and increased risk of hemorrhage. Due to these limitations a significant effort has been devoted towards development of newer anticoagulants. Dabigatran, Rivaroxaban, and more recently Apixaban have been approved by the F.D.A. for the prevention of stroke in patients with AF. These newer agents possess highly predictable pharmacokinetic and pharmacodynamics properties which allow a fixed dosing regimen and also eliminate the need of routine laboratory monitoring. This review discusses various anticoagulants for prevention of stroke in patients with AF.

Do Omega-3 Fatty Acids Decrease the Incidence of Atrial Fibrillation?

Citation : Peter Ofman, Adelqui Peralta, Peter Hoffmeister, J. Michael Gaziano, Luc Djousse

Although atrial fibrillation is a very common medical problem in general population and has a high incidence in the setting of open heart surgery, there are very few therapies to prevent occurrence or recurrence of atrial fibrillation. N-3 polyunsaturated fatty acids have been shown to change basic physiologic properties of the atrial tissue to make it less susceptible to atrial fibrillation. In this review, we first describe basic physiological mechanisms thought to be responsible for these changes and then discuss observational and interventional studies evaluating the use n-3 polyunsaturated fatty acids for primary and secondary prevention of atrial fibrillation in the general population, in subjects undergoing open heart surgery, and in special subgroups of patients.

Wednesday, July 17, 2013

Comparing Antiarrhythmic Drugs and Catheter Ablation for Treatment of Atrial Fibrillation

Citation : Andreas Rillig, Tina Lin, Feifan Ouyang, Karl-Heinz Kuck, Roland Richard Tilz

In the past years, catheter ablation has evolved into an effective treatment option for symptomatic, drug-resistant atrial fibrillation (AF) and it has recently been implemented as a primary treatment strategy for patients with paroxysmal AF. Although a significant number of studies have evaluated the potential benefits of catheter ablation compared with anti-arrhythmic drug (AAD)-therapy, to date, there are only a small number of randomized controlled trials in the literature, and several issues remain unsolved. The aim of this review is to analyze the current literature regarding this important issue and further discuss the question, whether catheter ablation may be more beneficial when compared to AAD therapy.

Anti-Arrhythmic Agents in the Treatment of Atrial Fibrillation

Citation : Omar F Hassan, Jassim Al Suwaidi, Amar M Salam

Although atrial fibrillation (AF) is the most common sustained arrhythmia seen during daily cardiovascular physician practice, its management has remained a challenge for cardiology physician as there was no single anti-arrhythmic agents proved to be effective in converting atrial fibrillation and kept its effectiveness in maintaining sinus rhythm over long term. Moreover all the anti-arrhythmic agents that are used in the treatment of AF were potentially pro-arrhythmic especially in patients with coronary artery disease and structurally abnormal heart. Some of these drugs also have serious non cardiac side effects that limit its long term use in the management of AF. Several new and investigational anti-arrhythmic agents are emerging but data supporting their effectiveness and safety are still limited.

In this review we examine the efficacy and safety of these medications supported by the major published randomized trials, meta-analyses and review articles.

Cardiac Remodeling After Atrial Fibrillation Ablation

Citation : Li-Wei Lo, Shih-Ann Chen

Radiofrequency catheter ablation procedures are considered a reasonable option for patients with symptomatic, drug refractory atrial fibrillation (AF). Ablation procedures have been reported to effectively restore sinus rhythm and provide long-term relief of symptoms. Both electrical and structural remodeling occurs with AF. A reversal of the electrical remodeling develops within 1 week after restoration to sinus rhythm following the catheter ablation. The recovery rate is faster in the right atrium than the left atrium. Reverse structural remodeling takes longer and is still present 2 to 4 months after restoration of sinus rhythm. The left atrial transport function also improves after successful catheter ablation of AF. Left atrial strain surveys from echocardiography are able to identify patients who respond to catheter ablation with significant reverse remodeling after ablation. Pre-procedural delayed enhancement magnetic resonance imaging is also able to determine the degree of atrial fibrosis and is another tool to predict the reverse remodeling after ablation. The remodeling process is complex if recurrence develops after ablation. Recent evidence shows that a combined reverse electrical and structural remodeling occurs after ablation of chronic AF when recurrence is paroxysmal AF. Progressive electrical remodeling without any structural remodeling develops in those with recurrence involving chronic AF. Whether progressive atrial remodeling is the cause or consequence during the recurrence of AF remains obscure and requires further study.

Cost-Effectiveness of Atrial Fibrillation Ablation

Citation : Gulmira Kudaiberdieva, Bulent Gorenek

Atrial fibrillation (AF) is a frequently encountered rhythm disorder, characterized by high recurrence rate, frequent hospitalizations, reduced quality-of-life and increased the risk of mortality, heart failure and stroke. Along with these clinical complications this type of arrhythmia is the major driver of health-related expenditures. Radiofrequency catheter ablation (RFA) of atrial fibrillation has been shown to improve freedom from arrhythmia survival, reduce re-hospitalization rate and provide better quality-of-life as compared with rate control and rhythm control with antiarrhythmic therapy. Efficacy of AF ablation in terms of outcomes and costs has an evolving importance.

In this review, we aimed to highlight current knowledge on AF ablation clinical outcomes based on results of randomized clinical trials and community-based studies, and overview how this improvement in clinical end-points affects costs for arrhythmia care and cost-effectiveness of AF ablation.

Effect of Age on Outcomes of Catheter Ablation of Atrial Fibrillation

Citation : Francia Rojas, Miguel Valderrábano

Age has a great impact in the development of atrial fibrillation, which is the most common arrhythmia found in the elderly. The higher risk of stroke, heart failure and mortality associated with atrial fibrillation highlights the need for successful therapeutic interventions that can translate in better outcomes in this population.
The introduction of catheter ablation has revolutionized the management of atrial fibrillation over the past decades with an undeniable impact in morbidity, mortality and quality of life. This benefit has not been fully extended to the older patients due to the lack of definitive data from randomized control trials assessing the impact of rhythm control strategies such as catheter ablation in this population, in whom a rate-control strategy has been suggested as a better therapeutic option.
In this review, we summarize the pathogenesis of atrial fibrillation in the elderly, the benefits and complications of catheter ablation reported in the literature and the impact of age in the outcomes of ablation compared to younger populations.

Monday, July 15, 2013

Catheter Ablation of Atrial Fibrillation in Females

Citation : Daniela Dugo, Stefano Bordignon, Laura Perrotta, Alexander Fürnkranz, KR Julian Chun, Boris Schmidt

Catheter ablation for the management of atrial fibrillation (AF) has evolved as a successful therapy widely used. Women with AF show a higher risk for AF-related morbidity due to stroke, a poorer tolerance to antiarrhythmic pharmacological therapy and a weaker quality of life; for this reason a curative, catheter-based approach for AF appears very attractive in women. Reported details on female AF population undergoing catheter ablation, as well as success and complication rates will be reviewed.

Contrast Induced Thyrotoxicosis in a Patient with New onset Atrial Fibrillation: A Case Report and Review

Citation : Jeffrey Adler, J. Colegrove

The development of thyrotoxicosis following the administration of iodinated contrast is a rare occurrence. The effect, referred to as the Jod-Basedow effect, is often observed in patients with underlying thyroid disease who develop thyrotoxicosis subsequent to the exposure of exogenous iodide. An example of an iatrogenic cause for this event may be seen when a large iodide load is given intravenously for studies or procedures. Thyrotoxicosis can also lead to cardiac arrhythmias including atrial fibrillation. This is a case presentation of a 74 year old female who developed thyrotoxicosis as well as new onset atrial fibrillation approximately one week after receiving iodinated contrast dye for a diagnostic CT of the abdomen. We further review the prior published literature in regard to atrial fibrillation and thyrotoxicosis.

Atrial Fibrillation Ablation in a Patient with Absent Pericardium

Citation : Vineet Kumar,Takumi Yamada, G. Neal Kay

A 45-year-old woman with drug-refractory paroxysmal atrial fibrillation (AF) underwent AF ablation. She had a history of abnormal chest radiograph, which on review was consistent with congenital absence of pericardium and this was later confirmed on cardiac magnetic resonance imaging. She had extreme leftward and posterior rotation of the heart, resulting in abnormal fluoroscopic appearance of the electrophysiological catheters and orientation of the interatrial septum. This along with exaggerated beat to beat motion of the heart posed significant technical challenges for the electrophysiologist during left atrial access and pulmonary vein isolation.

Left Atrial Appendage Thrombus Despite Anticoagulation

Citation : Viorel G. Floreaa, Venkatakrishna N. Tholakanahalli, Selcuk A. Adabag, Yellapragada Chandrashekhar

The American College of Cardiology Foundation/American Heart Association task force on practice guidelines recommend therapeutic anticoagulation for at least 3 weeks prior to cardioversion in patients with atrial fibrillation of 48-hour duration or longer, or when the duration of atrial fibrillation is unknown. This case report demonstrates the presence of thrombi in the left atrial appendage despite
adequate anticoagulation, challenging the current guidelines. Therapeutic anticoagulation for at least 3 weeks followed by transesophageal echocardiography in search of thrombus may enhance thromboembolic safety of elective cardioversion. Atrial fibrillation (AF) and heart failure (HF) have emerged as major cardiovascular epidemics in developed nations over the past decade. They share similar risk factors, seem to mutually accelerate progression and are associated with increased morbidity and mortality. Their relationship involves complex hemodynamic, neuro-hormonal, inflammatory and electrophysiologic mechanisms, which go beyond just mutual risk factors. This review focuses on updates in AF and HF with a hope of better understanding this relationship and the management of this complex duo.

CHADS2 and CHA2DS2Vasc-Score in Peripheral Systemic Embolism

Citation : Frans Santosa, Thomas Nowak, Theodoros Moysidis, Frank Eickmeier*, Christoph Stallinger, Bernd Luther, Kröger Knut

Objectives: We analysed the characteristics of patients with an acute peripheral embolic event considering the possible use of the CHADS2-Score and the CHA2DS2Vasc-Score

Patients and Methods: We retrospectively analyzed 163 cases of acute peripheral arterial embolism treated in the Department of Vascular Medicine of the HELIOS Klinik Krefeld, Germany, from 2008 to 2011. We retrospectively screened the medical form for information regarding atrail fibrillation (AF) and the risk factors necessary to calculate the CHADS2 and CHA2DS2vasc score.

Results: Arterial hypertension and age > 75 years were the most frequent risk factors. Mean CHADS2 score was similar in males and females (2.3 ± 1.5 and 2.3 ± 1.4). 66% of the males and 63.3% of the females scored 2 and more points. Mean CHA2DS2Vasc score was 3.6 ± 2.0 in males and 4.6 ± 1.9 in females. 85.2% of the males and 95.4% of the females scored more than 2 points.

In the medical forms AF was documented in 79 (48%) patients, of which 23 (43 %) were males and 56 (51%) females. Mean CHADS2 score and mean CHA2DS2Vasc score were slightly higher in those with AF compared to the total group, but not significantly different. The rate of patients with 2 and more points increased for both scores: CHADS2 score: males 82.6% and females 76.8%, CHA2DS2Vasc: males 100% and females 98.2%. Almost half of the patients with AF had anticoagulation with phenprocoumon before (males 12 (52%), females 24 (43%), but only every 10th was within the therapeutic range (INR ≥2)

Conclusion: The number of those with AF is high amongst patients with acute peripheral embolism. According to the CHADS2 and CHA2DS2Vasc score, most of these patients had an indication for oral anticoagulation independent form the embolic event.

Friday, July 12, 2013

The Future of Fluoroless Cardiovascular Interventions

Citation : Charlotte Eitel, Christopher Piorkowski, Thomas Gaspar, Philipp Sommer, Gerhard Hindricks

Fluoroscopy is still the standard technique for guidance of cardiovascular interventions due to fast and instantaneous generation of twodimensional projections of the cardiac contour and any fluoroscopically visible device. However, it is associated with significant radiation exposure to the patient and the operator and information on the underlying three-dimensional anatomy is limited. With a growing amount of complex cardiovascular procedures, radiation exposure with potential detrimental effects increases for both the patient and the operator, who is often exposed over many years. Therefore efforts are made to reduce radiation exposure on the one hand and to enhance understanding of the underlying anatomical substrate with the aim of improving outcomes and reducing complications on the other hand.

The most promising technology that might facilitate completely non-fluoroscopic cardiovascular interventions in the future is real-time magnetic resonance imaging (MRI). Several characteristics of MRI make this imaging technology particularly attractive to guide cardiovascular interventions. Benefits relate to (1) the fluoroscopy-free environment, (2) substrate analysis, (3) combination of three-dimensional anatomical and functional information and (4) lesion visualization. The safety and feasibility of real-time MRI guided electrophysiology studies and first ablation procedures in humans have been described recently. Nevertheless these experiences are limited to few centers and widespread application is still limited. This article will discuss advantages, challenges and limitations of real-time MRI procedures.

Initial Experience with MediguideTM Technology in Cardiac Resynchronization Therapy Device Implantation

Citation : E. Kevin Heist, Moussa Mansour, Jeremy Ruskin

Cardiac Resynchronization Therapy (CRT) is an important and expanding treatment for systolic heart failure associated with ventricular dyssynchrony. CRT implant procedures are frequently associated with prolonged radiation exposure which is typically substantially greater than exposure from conventional single and dual chamber devices, and which increases the risk of radiation-induced illness, particularly cancer, for both patients and implanting physicians and staff. MediGuide™ technology has been developed for CRT implantation, involving miniature sensors located in inner and outer guiding catheters and in the .014” guidewire which can be tracked in 3 dimensional space without the need for fluoroscopy during large portions of left ventricular lead implantation. Early results from pre-clinical and clinical implants have demonstrated significant decreases in fluoroscopic exposure when MediGuide™ is used to guide CRT placement. In this chapter, we discuss the MediGuide™ tools which are currently developed for CRT, describe the implant technique using this technology, and report the experience to date with this approach.

Early Experience with MediGuide™ Technology in Ventricular Tachycardia Ablation

Citation : Christopher Piorkowski, Gerhard Hindricks, Thomas Gaspar

Background: With an increasing number of long and complex procedures for the treatment of ventricular tachycardia, fluoroscopy reduction plays an important role in the safety of patients, physicians and medical staff. We describe the clinical use of a novel fluoroscopyimitating 3D cardiovascular navigation system for VT ablation.

Methods: 14 patients with ischemic or dilated cardiomyopathy underwent VT ablation between May and October 2012 using a 4D cardiovascular navigation system (MediGuide™). The real-time position of sensor-enabled electrophysiology diagnostic and ablation catheters were projected onto pre-recorded ventriculogram cine loops. Ablation was guided by local activation time (LAT) maps, pace maps, and substrate maps of the LV within 3D chamber geometries of the co-registered impedance base mapping technology (NavX-EnSite).

Results: Ablation was performed successfully in all 14 patients. Of the 14 ablated patients, 11 (79%) were free of VT after a median followup time of 90 (IQR 60-143) days. There were no major complications, especially no pericardial effusion. Fluoroscopy time for preparation (catheter insertion, transseptal puncture, and LV angiograms) was 1.5 (IQR 1.0-5.1) min, with a dose of 2302 (IQR 1593-3131) μGy-m2. For mapping and ablation, fluoroscopy time was 0 (IQR 0-8.2) min, with a dose of 0 (IQR 0-1032) μGy-m2. In 9/14 (64%) patients lead protection was completely taken off after the preparation.

Conclusions: The data describe early experience with the MediGuide™ technology in patients with VT ablation. Usage of the technology was safe and clinically effective. This preliminary data indicate a significant potential for substantial reduction of radiation exposure during such complex and lengthy interventions.

Role of MediGuideTM Technology in Atrial Fibrillation Ablation

Citation : Philipp Sommer, Sascha Rolf, Gerhard Hindricks

Background: Recently, a new technological platform has been introduced allowing almost non-fluoroscopic ablations in right atrial ablations like typical atrial flutter. We describe our first experience with the MediGuide®-technology in AF ablations. This technology platform allows non-fluoroscopic catheter visualization on prerecorded cine-loops and can contribute to significant reduction in radiation exposure. 

Methods: All patients ablated for AF in our institution with MediGuide™-Technology are enrolled in a registry. All procedural data, namely fluoroscopy time and dose, procedure time and acute success were analysed. We report on our initial 100 AF patients since the MediGuide enabled ablation catheters became available (May 2012).

Results: Some changes in the procedure workflow were made to optimally adapt to the opportunities of the MediGuide system. The overall procedure time was not prolonged as compared to conventional ablation procedures. Both the radiation dose and the fluoroscopy time were dramatically reduced as compared to standard ablations (4.3 ± 2.5min vs. 29 ± 5min; p<0.001), the radiation dose was 2412 ± 380 cGy cm² and the procedure time was 171 ± 32min. No adverse events associated with the use of the system were seen.

Conclusions: The MediGuide™ Technology allows safe AF ablation procedures with a significant reduction in fluoroscopy time and dosage. In daily practice, fluoroscopy times of 3min and less and dosages of <1000cGy/cm² are common. Procedure times for AF ablation procedures were not prolonged by the application of this new non-fluoroscopic catheter tracking technology and complication rate was not increased compared to conventional procedures.

Evolution of Medical Positioning System - Understanding How MediguideTM Technology Works

Citation : Dan Blendea, E. Kevin Heist, Jeremy Ruskin, Moussa Mansour

Conventional fluoroscopy is the main imaging modality for intracardiac catheter tracking in interventional cardiovascular procedures. It has the advantage of being able to instantaneously localize the catheter and its spatial relationship with respect to the moving target organ. However, fluoroscopy only provides 2-D orientation, and has significant radiation exposure. For treatment of complex cardiac arrhythmias 3-D mapping technologies have been introduced to facilitate spatial, anatomic, and electrical orientation. A new technological platform (MediGuide) offers the option to continuously display the catheter tip on a prerecorded cine-loop allowing better anatomic understanding of the underlying substrate. This review article describes the MediGuide technology and its advantages.

Current State of Radiation Protection in Electrophysiology Laboratory

Citatiion : Ryan Maybrook1, Madhu Reddy, Ajay Vallakati1, Pramod Janga, Sudharani Bommana, Andrea Natale, Dhanunjaya Lakkireddy

Invasive cardiology procedures have increased in complexity over the last decade, likely due to an aging population, higher prevalence of cardiovascular disease, and newer technologies in the cardiovascular laboratory requiring high levels of technical understanding. While radiation reduction techniques have improved, there is still a real risk of potentially significant radiation exposure if methods for radiation protection are not utilized. Radiation protection is essentially divided into two components: personal protection and external protection. Personal protective equipment, consisting of a lead apron, eye glasses, and thyroid shield is the cornerstone of radiation safety. Federal advisory committees such as The International Commission on Radiation Protection (ICRP) provide recommendations regarding minimum lead thickness for these essential elements. External protective equipment including hanging shields, table skirts, radiation drapes, rolling shields, sound radiation-proof lab architecture, and radiation protection units all comprise the remaining tools for radiation protection in the laboratory. While there are certain limitations to all forms of radiation protection, the benefits generally outweigh the risks. And in the case of radiation exposure, risks such as biologic side effects can have permanent implications. Recent literature has specifically highlighted cataract and brain tumor formation in operators. This review is thus meant to afford the reader a rather comprehensive review of the currently available radiation protection tools and provide evidence-based, practical tips on their incorporation into daily use.

Tools and Tips for Effective Radiation Protection

Citation : Petr Peichl, Josef Kautzner

The number and complexity of invasive electrophysiological procedures have dramatically increased over the last decades. Despite recent technological advances, the use of fluoroscopy remains the main visualization technique for intracardiac catheter positioning. The purpose of radiation protection tools is to improve operator and staff safety without impeding the procedure or jeopardizing the patient’s safety. There are three types of radiation shielding: architectural shielding, equipment-mounted shields, and personal protective devices, which include aprons, thyroid shields, eyewear and gloves. Due to the documented increase in orthopedic problems in interventionalists, which are believed to be related to long-term use of heavy radiation protective garments, the mobile radiation protection cabins have been developed to replace their use. The mobile cabins may be either floor mounted on wheels or ceiling mounted on a suspension that moves with the operator. This review focuses on the different tools currently available for radiation protection in the setting of electrophysiology laboratory.

Wednesday, July 10, 2013

The Role of 3D Mapping Technology and Fluoro Reduction in the Electrophysiology World

Citation : Carlo Pappone, Gabriele Vicedomini, Vincenzo Santinelli

Catheter ablation has become a standard therapeutic option for the management of many arrhythmias, including atrial fibrillation, atrial tachycardia and ventricular tachycardia with an increasing number of ablation procedures worldwide. Although conventional fluoroscopy has been and remains the main technology for catheter tracking, concerns about long-term effects of radiation exposure on patients and operators have stimulated the use of nonfluoroscopic 3D systems and interest in their use is growing rapidly worldwide. Beside the associated significant X-ray exposure, fluoroscopy only provides 2D orientation. For complex anatomies and substrates mapping, nonfluoroscopic 3 dimensional technologies are routinely used to facilitate catheter navigation for successful ablation while minimizing or eliminating fluoroscopy exposure. There are many 3D fluoroless systems available such as the CARTO and Ensite systems which have been conceived to provide the ability to monitor catheter movement without fluoroscopy, as well as to create cardiac geometry and monitor marked mapping and ablation points. New software upgrades to nonfluoroscopic 3D mapping have resulted in very detailed cardiac chambers, potentially eliminating preprocedure computed tomography imaging. More recently, a novel sensor-based 3D catheter tracking system integrating 3D non-fluoroscopic catheter navigation into prerecorded conventional 2D fluoroscopy (MediGuide technology) has been proposed with the possibility of a procedure without fluoroscopy. This chapter will summarize the most recent developments and the latest findings in catheter navigation and 3D electroanatomic mapping systems. Although these new systems are routinely used worldwide, in our opinion they cannot completely replace careful interpretation of electrophysiology data particularly in the management of complex arrhythmias.

Basic Steps to Reduce Radiation in Cardiovascular Laboratory

Citation : Ajay Vallakati, Madhu Reddy, Pramod Janga, Karthik Murugiah, Gopi Manohar Ponnaganti, Sudharani Bommana, Andrea Natale, Dhanunjaya Lakkireddy

One hundred and thirteen years after the discovery of X-rays, these electromagnetic waves continue to be the most commonly used technology for imaging in the field of medicine. Despite significant advances in x-ray technology, the amount of radiation exposure in the cardiovascular laboratory has not decreased as it should have. Different regulations have been promulgated to address the issue of radiation exposure in health care facilities. Today, the procedures are performed guided by ALARA principle, which recommends that radiation exposure be limited to As Low As Reasonably Achievable. In this article, we discuss the historical background, different steps to reduce radiation in cardiovascular laboratory and the few innovations that are directed at reducing radiation exposure.

Hospital and Physician Financial Impact and Risk Profile of Medical Radiation

Citation : Gery F. Tomassoni

Recent advances in the field of interventional cardiology, electrophysiology (EP), and medical imaging have been associated with increased utilization of ionizing radiation. EP fluoroscopic guided procedures including complex catheter ablation and implantation of cardiac resynchronization therapy (CRT) devices have resulted in high radiation exposures to patients, medical staff, and electrophysiologists. The short-term effects of high radiation exposures can result in temporary suspension of lab personnel including both medical staff and physicians. However, the long-term effects more importantly can lead to patient health complications and physician/lab staff occupational
hazards such as orthopedic complications and radiation-induced illnesses. The monetary impact can be significant resulting in substantial financial losses to the hospital and physician.

Financial losses related to medical radiation exposure are increasingly incurred by both the hospital and interventional electrophysiologists. The hospital costs include 1) loss of revenue due to physician and/or medical staff being “benched” due to excessive radiation exposure, 2) the added costs of salary payment for the non-producing electrophysologist or staff, 3) costs of health, disability, and liability insurance to treat physician and lab personnel complications of orthopedic and radiation-induced illnesses, and 4) possible patient medico-legal payments as a result of lawsuits due to health issues from high radiation exposure. As more physicians are leaving their practice to become hospital employees, the financial impact on the hospital will be even more burdensome. Financial losses to the electrophysiologists can be due to restricted laboratory time and procedures as a result of high radiation exposure and time off from orthopedic complications from chronic use of wearing lead aprons or in the treatment of radiation-induced illnesses.

As a result of the clear financial impact and medical risks to the hospital, physician, and patient, it will become increasingly important to ensure the adoption of institutional policies, the implementation of sound working practices, and essential training of the lab staff and physician to lower radiation exposure complications. Efforts are needed now to create a radiation-safe working environment with the goal to reduce radiation exposure and prevent both health-related complications and unnecessary financial losses.

Specific Risks to Patients and Medical Professionals from Radiation Exposure

Citation : Abhinav Sharma, Madhu Reddy, Ajay Vallakati, Pramod Janga,Nirbhay Parashar, Sudharani Bommana, Buddhadeb Dawn, Dhanunjaya Lakkireddy

Contemporary cardiovascular medicine utilizes several tests and procedures that involve the use of ionizing radiation. The use of cardiac imaging has increased several fold in the last three decades with concomitant improvement in cardiovascular outcomes. These tests and procedures, namely, myocardial perfusion imaging and other forms of nuclear cardiac imaging, computed tomography scans, and x-ray fluoroscopy- guided procedures that are performed in the cardiac catheterization laboratory predispose both the patients as well as the interventional staff to the deterministic and stochastic effects of low dose radiation. In this article, we discuss the radiation risks from cardiovascular imaging to both patients and medical staff as well as balancing the risks and benefits of cardiac imaging for the patient.

Radiation Exposure in the Cardiovascular Space

Citation : Katia Dyrda, Peter G. Guerra, Laurent Macle

The fields of interventional cardiology and electrophysiology were developed based on the use of fluoroscopic guidance. With time, there has been a significant increase in the number of pathologies treatable by interventional approaches, and the number, complexity and the availability of these procedures have likewise increased, resulting in greater radiation exposure to patients, physicians and allied health professionals. In parallel, different navigational systems have successfully been developed to attempt to decrease radiation exposure. The current paper aims to survey these medical advances and explore past and present radiation exposures in the cardiovascular space.

Evolution of International Standards and Limits on Radiation Exposure for Medical Professionals and General Public

Citation : Ajay Vallakati, Santhosh Reddy Mannem, Madhu Reddy, Ryan Maybrook, Pramod Janga, Gopi Manohar Ponnaganti, Sudharani Bommana, Andrea Natale, Dhanunjaya Lakkireddy

Since the discovery of radiation more than 100 years ago, the philosophy of radiation protection has gradually evolved from prevention of deterministic effects to decreasing the risk of malignancy. The present radiation protection standards are based on principles of justification, optimization and dose limitation. In this article, we discuss the evolution of international standards, current standards and ALARA principle.

Biological Effects of Ionizing Radiation

Citation : Arun Kanmanthareddy, Avanija Buddam, Madhu Reddy, Pramod Janga, Ajay Vallakati, Vivek Yarlagadda, Sudharani Bommana, Dhanunjaya Lakkireddy, Andrea Natale

Ionizing radiation (IR) is electromagnetic wave of high frequency and small wavelength capable of ionizing tissues and damages cells in multiple ways. Components of radiation are used for diagnostic studies such as X-rays, CT scans and fluoroscopy and therapeutically for treating malignancy. Unfortunate incidents like atomic bombing in Japan, Chernobyl nuclear leak, nuclear weapons testing sites in various countries have exposed people to radiation on a large scale. The long-term effects of IR in these population groups are still being studied. IR causes damage to the cells by producing free radicals and causes alterations in the DNA. The resulting oxidative stress causes production of cytokines, which mediate the inflammatory process. DNA alterations can result in mutated cells and neoplastic transformation. Deterministic effects occur at a particular threshold level of radiation and their severity increases with increasing dose, while stochastic effects such as malignancy may occur at a threshold dose, but the severity of effect is independent of the dose.

Acute radiation syndrome occurs when subjects are exposed to high dose radiation over a short period of time and can have devastating outcomes. Bone marrow failure occurs at doses >2Gy and gastrointestinal and neurovascular complications occurs with doses >5-10Gy. Chronic effects of radiation depend on the tissue, the dose and duration of exposure. Different tissues vary in their sensitivity to radiation; hematopoietic and reproductive systems are the most sensitive to radiation. Leukemia was the first non-acute effect observed in atom-bomb survivors, followed by solid tumors over the course of several years. Cardiovascular events such as myocardial infarction and stroke were also increased in populations exposed to radiation. Radiation therapy used in the treatment of malignancies also causes multiple adverse effects involving several organ systems. Medical radiation used for diagnostic purposes is considered safe, but repeated exposures to patients and personnel might increase the cumulative risk for adverse effects. Thus it is important to understand the harmful biological effects of radiation and every possible effort should be made to minimize radiation risk to patients and operators administering and performing these procedures.

Fundamentals of Radiation Exposure

Citation : Santhosh Reddy Mannem, Ajay Vallakati, Madhu Reddy, Ryan Maybrook, Pramod Janga, Gopi Manohar Ponnaganti, Sudharani Bommana, Andrea Natale, Dhanunjaya Lakkireddy

Presence of radioactive energy was discovered more than 100 years ago. We are exposed to ubiquitous background radiation as well as anthropogenic sources of radiation in our day to day life. Exposure to ubiquitous background radiation has not increased significantly over the last 25 years. On the other hand, the amount of radiation exposure from medical sources has increased dramatically due to increased utilization of technology like computed tomography, nuclear medicine and interventional fluoroscopy. In this article, we describe the different kinds of radiation, sources of radiation and various measures of radiation exposure.

Monday, July 8, 2013

Why Should We Not Delay Ablation in New Onset Recurrent Atrial Fibrillation

Citation : Paramdeep S Dhillon, PhDa, Riyaz Kabaa,b, David E Ward, MD

Recurrent episodes of atrial fibrillation are associated with progressive left atrial substrate remodelling over time. We present an argument for early ablation in the treatment of recurrent paroxysmal atrial fibrillation prior to such deleterious changes in “left atrial electrical health”

Alternative Therapies in the Treatment of Atrial Fibrillation

Citation : Federico Lombardi, MD, FESC; Sebastiano Belletti, MD; Alberto Lomuscio, MD

Atrial fibrillation (AF) is the most common clinical arrhythmia and represents a major social and economic problem. The number of subjects with AF is constantly increasing as a result of aging and improved survival in several cardiac and non-cardiac diseases. Patients with AF are often symptomatic, have a reduced physical capacity and are at high risk for thromboembolic events. Moreover, AF is associated with increased mortality and independent of the management, based either on rhythm or rate control strategy, The safety and efficacy of most anti-arrhythmic drugs are questionable. Increasing attention has therefore been addressed to evaluate the possible therapeutic and/or preventive effects of forms of treatment coming from ancient medical traditions of Far East, like acupuncture and yoga. In traditional Chinese medicine, acupuncture has been found effective in managing patients with paroxysmal supraventricular tachycardia. Recently, also in the Western literature, reports have been published supporting the clinical efficacy of acupuncture to treat arterial hypertension and to reduce chest pain. Other studies have evaluated the effects of acupuncture and other methods of Eastern Medicine, i.e., Qigong, Tai Chi Chuan and Yoga, in the treatment of cardiac illnesses associated with supraventricular arrhythmias.

Two reports on the effects of acupuncture in preventing or reducing the rate of AF recurrences in patients with persistent or paroxysmal AF have been recently reported . Another ancient traditional eastern form of therapy and prevention, i.e., yoga, has been recently shown to reduce episodes of atrial fibrillation and improve the symptoms of anxiety and depression often associated with this arrhythmia. Growing evidence indicates that acupuncture and yoga are safe, without any pro-arrhythmic effect and with limited cost. All these factors should be considered when evaluating the efficacy of therapeutic intervention for an epidemic disease such as AF.

Prerequisites for Exploring Predictors of Chronic Atrial Fibrillation Recurrence After Ablation

Citation : Mahito Noro, MD, PhD

The ablation treatment for the atrial fibrillation extends to the persistent atrial fibrillation now. However, the cure rate of persistent atrial fibrillation by Radiofrequency Ablation is lower than paroxysmal atrial fibrillation and we really want to know is the information that what kind of persistent atrial fibrillation ablation therapy is effective for. Therefore, it is wished the predictors of recurrence after the ablation for the persistent atrial fibrillation is confirmed, but does not yet confirm. The cause that is not confirmed seems to be present in many factors including the gene which the atrial fibrillation occurs in and persist, the change of pathology into remodeling according to progression of atrial fibrillation and strategy of the ablation corresponding to them. Left atrium diameter, Duration of atrial fibrillation and Cardiac Function that are involved deeply in atrial muscle and electric remodeling, and Ablation strategy corresponding to them are considered based on the conventional report. It can be stated now, however, that persistent atrial fibrillation patients with some degree (although this “some degree” has not been clearly defined) of enlarged left atrium diameter, prolonged atrial fibrillation duration, or decreased cardiac function may also revert to sinus rhythm with Radiofrequency Ablation, more efficient treatment may be developed in the future and reversion to sinus rhythm may increase the benefit to patients. In summary, RF ablation for persistent AF is currently required with further study of the predictors of recurrence after the ablation for the persistent atrial fibrillation.

Dronedarone: Where Does it Fit in the AF Therapeutic Armamentarium?

Citation : James A. Reiffel, M.D

Dronedarone is a derivative of amiodarone with similar mechanisms of action (blocking calcium, potassium and sodium channels in addition to having anti-adrenergic effects). Compared to amiodarone it has fewer drug interactions (though it can interact with all current anticoagulants), more limited risk of organ toxicity, a much shorter half-life with no need for a loading regimen, but lower efficacy. Dronedarone is approved for the treatment of atrial fibrillation; has had limited studies for other arrhythmias; and has no adverse drug-ICD interactions reported. Clinical trials have resulted in only one dosing regimen (400 mg bid, to be taken with food) and have demonstrated both rate and rhythm effects in atrial fibrillation (AF). Dronedarone slows the ventricular response, can prolong the time to/reduce recurrences of/ reduce progression of AF, and reduce the incidence of hospitalization in AF patients with risk-prone markers. However, trials have also revealed an increased risk of mortality and other adverse cardiovascular outcomes from dronedarone when given to patients in heart failure. The details of these trials, additional pharmacokinetic and pharmacodynamic information, and recommendations concerning the use of dronedarone are provided in the full manuscript that follows.

Ischemic Conditioning and Atrial Fibrillation: Hope for a NewTherapy?

Citation : Heiko Schmitt M.D., Bruce T. Liang M.D., Christopher Pickett M.D

Atrial fibrillation (AF) is the most common sustained arrhythmia. It is accompanied by both structural and ion channel remodeling which underlie the propensity to perpetuate AF. The prevalence of AF is expected to increase as population ages and as more patients survive myocardial infarction. Despite pharmacological and nonpharmacological (such as ablation) therapies for AF, more effective therapy is needed. Ischemic or pharmacological conditioning offers a potential novel approaches to patients with AF. This review will focus on the basic biology of ischemic pre- and postconditioning, patho-physiology of AF, potentially novel AF treatment approaches based on conditioning, and clinical situations that may be amenable to a conditioning strategy.

Post-operative Atrial Fibrillation – Pathophysiology, Treatment and Prevention

Citation: E Bidar, S Bramer, B Maesen, J G Maessen, U Schotten

Atrial fibrillation occurring after cardiac surgery has been the subject of intensive research over the past decades. However, the incidence remains high, despite numerous preventive and treatment strategies. In addition, several reports show that the impact of post-operative atrial fibrillation (POAF) is high. It is an independent risk factor for mortality after several years. These findings make clear that the pathophysiology of POAF is not fully understood and POAF-associated risks to some extent might be underestimated. On the one hand, excessive triggers during the acute post operative phase after cardiac surgery might initiate AF even in atria with low vulnerability. On the other hand, many patients undergoing surgery have an atrial substrate at the time of operation promoting AF not only in the post-operative phase but also in the days and weeks thereafter. Progress in our understanding of the AF mechanisms in general has provided valuable insights into processes involved in atrial structural remodeling due to advanced age, hypertension, obesity, and congestive heart failure. These patient characteristics strongly contribute to cardiac disease, predict POAF and likely have an impact on the risk of thrombus formation in the weeks and months after cardiac surgery. For a better understanding of the mechanisms involved, it is important to not only recognize the occurrence of POAF by continuous monitoring after surgery, but also to identity the extent of atrial vulnerability to AF in these patients.

Role of Intracardiac Echocardiography in Atrial Fibrillation Ablation

Citation: Antonio Dello Russo, MD PhD, Eleonora Russo, MD, Gaetano Fassini, MD, Michela Casella, MD PhD, Ester Innocenti, MD, Martina Zucchetti, MD, Claudia Cefalu’, MD, Francesco Solimene, MD , Gaetano Mottola, MD, Daniele Colombo, MD, Fabrizio Bologna, MD, Benedetta Majocchi, MD, Pasquale Santangeli, MD, Stefania Riva, MD, Luigi Di Biase, MD, PhD, Cesare Fiorentini, MD, and Claudio Tondo, MD PhD

In the recent years, several new evidences support catheter-based ablation as a treatment modality of atrial fibrillation (AF). Based on a plenty of different applications, intracardiac echocardiography (ICE) is now a well-established technology in complex electrophysiological procedures, in particular in AF ablation. ICE contributes to improve the efficacy and safety of such procedures defining the anatomical structures involved in ablation procedures and monitoring in real time possible complications. In particular ICE allows: a correct identification of the endocardial structures; a guidance of transseptal puncture; an assessment of accurate placement of the circular mapping catheter; an indirect evaluation of evolving lesions during radiofrequency (RF) energy delivery via visualization of micro and macrobubbles tissue heating; assessment of catheter contact with cardiac tissues. Recently, also the feasibility of the integration of electroanatomical mapping (EAM) and intracardiac echocardiography has been demonstrated, combining accurate real time anatomical information with electroanatomical data. As a matter of fact, different techniques and ablation strategies have been developed throughout the years. In the setting of balloon-based ablation systems, recently adopted by an increasing number of centers, ICE might have a role in the choice of appropriate balloon size and to confirm accurate occlusion of pulmonary veins. Furthermore, in the era of minimally fluoroscopic ablation, ICE has successfully provided a contribute in reducing fluoroscopy time.

The purpose of this review is to summarize the current applications of ICE in catheter based ablation strategies of atrial fibrillation, focusing-on electronically phased-array ICE.