Monday, March 21, 2011

Septic Shock due to Implantable Cardiac Defibrillator Related Infection

Citation : David Palmer, Aleem Khand.Septic Shock due to Implantable Cardiac Defibrillator Related Infection .JAFIB.2011 February;Volume 2 Issue(4): 888-890.

Infection is an important complication of cardiac device implantation. We report the case of a 61 year old patient presenting with septic shock caused by cardiac device infection (CDI) three-weeks after device implantation. At initial presentation, there was an absence of both localising signs and echocardiographic evidence of CDI. Later, Staphylococcus aureus was cultured from blood and the pre-pectoral pocket. 48 hours after admission the device and leads were explanted in theatre by simple traction. Despite appropriate antibiotics and full supportive care (including haemofiltration, ventilation and inotropic support), the patient died on day six. Cardiac device infection may present with septic shock in the absence of localising features. A high index of suspicion is required, particularly for early CDI.

Role of Remote Navigation Systems in AF Ablation

Citation : Boris Schmidt, Britta Schulte-Hahn, Bernd Nowak, Verena Windhorst, Kyoung Ryul Julian Chun.Role of Remote Navigation Systems in AF Ablation .JAFIB.2011 February;Volume 2 Issue(4): 881-887.
During the past decade atrial fibrillation (AF) ablation has developed from being an experimental treatment option to an evidence based therapy implemented in current guidelines. Irrigated radiofrequency current guided ablations remain the golden standard of pulmonary vein isolation (PVI) procedures. Although practiced more frequently, it remains a demanding procedure requiring skilful operators. Novel technologies such as balloon based catheters or remote navigation (RN) systems have been developed to overcome the pitfalls of manual ablation procedures.

The Cost of Thromboembolic Events and their Prevention among Patients with Atrial Fibrillation

Citation : Thomas Davidson, Magnus Husberg, Magnus Janzon, Lars-Ake Levin. The Cost of Thromboembolic Events and their Prevention among Patients with Atrial Fibrillation .JAFIB.2011 February;Volume 2 Issue(4): 870-880.

Aim: Atrial fibrillation (AF) is the most common type of cardiac arrhythmia. People with AF have a significantly increased risk of thromboembolic events, including stroke, and the main treatment is therefore aimed at preventing thromboembolic events via anticoagulation with warfarin or acetylsalicylic acid. However, the development of new anticoagulation treatments has prompted a need to know the current cost of AF-related thromboembolic events, for future cost-effectiveness comparisons with the existing treatments. In this study, we estimated the cost of thromboembolic events and their prevention among Swedish AF patients in 2010.

Methods: The relevant costs were identified, quantified, and valued. The complications included were ischaemic and haemorrhagic stroke, gastrointestinal bleeding, and other types of major bleeding caused by AF. Treatments intended to lower the risk of ischaemic stroke were also included. A societal perspective was used, including productivity loss due to morbidity. Patients with a CHADS2 score of 1 or higher were included.

Results: Among the 9 340 682 inhabitants of Sweden, there are 118 000 patients with AF and at least one more risk factor for stroke, comprising 1.26% of the population. Of these patients, 43.3% are treated with warfarin, 28.3% use acetylsalicylic acid, and 28.3% are assumed to have no anticoagulation treatment. The cost of AF-related complications and its prevention in Sweden was estimated at €437 million for 2010, corresponding to €3 712 per AF patient per year. The highest cost was caused by stroke, and the second highest by the cost of monitoring the warfarin treatment. As the prevalence of AF is expected to increase in the future, AF-related costs are also expected to rise.

Conclusion: Thromboembolic events cause high costs. New, easily-administered treatments that could reduce the risk of stroke have the potential to be cost-effective.

Cardiac Image Registration: Rotational Error Correction and Gated Stabilization for Cardiac Motion

Citation : Jasbir Sra.Cardiac Image Registration: Rotational Error Correction and Gated Stabilization for Cardiac Motion .JAFIB.2011 February;Volume 2 Issue(4): 856-869.

Background: Dynamic motion of the heart due to cardiac and respiratory cycles, and rotation from varying patient positions between imaging modalities, can cause errors during cardiac image registration. This study used phantom, patient and animal models to assess and correct these errors.

Methods and Results: Rotational errors were identified and corrected using different phantom orientations. ECG-gated fluoro images were aligned with similarly gated CT images in 9 patients, and accuracy assessed during atrial fibrillation (AF) and sinus rhythm. A tracking algorithm corrected errors due to respiration, where 4 independent observers compared 25 respiration sequences to an automated method. Following correction of these errors, target registration error was assessed. At 20 mm and 30 mm from the phantom model\’s center point with an in-plane rotation of 8 degrees, measured error was 2.94 mm and 5.60 mm, respectively, and the main error identified. A priori method accurately predicted ECG location in only 38% (p=0.0003) of 313 R-R intervals in AF. A posteriori method accurately gated the ECG during AF and sinus rhythm in 97% and 98% of 375 beats evaluated, respectively (p=NS). Tracking algorithm for ECG-gated motion compensation was identified as good or fair 96% of the time, with no difference between observers and automated method (chi-square=25; p=NS). Target registration error in phantom and animal models was 1.75±1.03 mm and 0 to 0.5 mm, respectively.

Conclusions: Errors during cardiac image registration can be identified and corrected. Cardiac image stabilization can be achieved using ECG gating and respiration.

Monday, January 3, 2011

Anticoagulation after Atrial Fibrillation Ablation: Many Blanks to Fill

Citation : Martin Fiala.Anticoagulation after Atrial Fibrillation Ablation: Many Blanks to Fill .JAFIB.2010 December;Volume 2 Issue(3): 853-855.

Long-term maintenance of sinus rhythm (SR) after catheter ablation of atrial fibrillation (AF) has remained an open issue awaiting further relevant data. It is of paramount importance as our everyday decisions on discontinuing anticoagulation after ablation rest on the belief in the absence of clinically significant asymptomatic AF episodes and constant SR for the rest of the patient\'s life. Both aspects are difficult to ascertain, for the tools of truly continuous ECG monitoring are not comfortably applicable, and routine follow-up tends to thin out beyond 1 year in asymptomatic patients without apparent arrhythmia recurrences.

Atrial Tachycardia Successfully Ablated from the Left Coronary Sinus Cusp of the Aorta: An Unusual Site of Origin

Citation : Takumi Yamada.Atrial Tachycardia Successfully Ablated from the Left Coronary Sinus Cusp of the Aorta: An Unusual Site of Origin .JAFIB.2010 December;Volume 2 Issue(3): 851-852.

It has been recognized in the last decade that atrial and ventricular tachycardias may arise from the myocardium around the aorta. These tachycardias can be ablated from the coronary sinus cusps of the aorta (ASCs). In some of those tachycardias, the site of origin may be epicardial and thus can be ablated only through the thin structure of the ASCs. It is important to know how to make a diagnosis, map and ablate tachycardias arising from this region.

The Use of Cryoballoon Ablation in Atrial Fibrillation: Simplifying Pulmonary Vein Isolation?

Citation : Gian Battista Chierchia, Antonio Sorgente, Andrea Sarkozy, Carlo de Asmundis, Pedro Brugada.The Use of Cryoballoon Ablation in Atrial Fibrillation: Simplifying Pulmonary Vein Isolation? .JAFIB.2010 December;Volume 2 Issue(3): 839-850.

Atrial fibrillation (AF) is certainly the most common arrhythmia encountered in clinical practice, reaching epidemic proportions in occidental society. Nowadays, transcatheter ablation using radiofrequency (RF) has become a popular technique in the treatment of drug-resistant AF. Since ectopic beats originating from the pulmonary veins (PVs) have been shown to be the main trigger initiating AF, electrical isolation of these venous structures has become the goal when performing this procedure.

Atrial Fibrillation after Cardiac Surgery: Benign or Deserving of Prophylaxis

Citation : Stephen Westaby.Atrial Fibrillation after Cardiac Surgery: Benign or Deserving of Prophylaxis .JAFIB.2010 December;Volume 2 Issue(3): 835-838.

New onset atrial fibrillation (AF) is the commonest complication after cardiac surgery affecting around 30% of coronary artery bypass graft (CABG) patients, up to 50% of valve surgery patients and as many as 60% of those undergoing combined valve and CABG operations.

Gender and Racial Characteristics of Patients Referred to a Tertiary Atrial Fibrillation Center

Citation : Pamela K. Mason, Liza Moorman, Douglas E. Lake, J. Michael Mangrum, John P. DiMarco, John D. Ferguson, Srijoy Mahapatra, Kenneth C. Bilchick, David Wiggins, J. Paul Mounsey, J. Randall Moorman.Gender and Racial Characteristics of Patients Referred to a Tertiary Atrial Fibrillation Center .JAFIB.2010 December;Volume 2 Issue(3): 827-834.

Atrial Fibrillation Centers (AFCs) are becoming increasingly common and are often developed at institutions to provide comprehensive evaluation and management for patients with atrial fibrillation (AF) including catheter and surgical ablation. Studies have shown that women and racial minority patients are less likely to be offered aggressive or invasive therapies. The University of Virginia (UVA) AFC was opened in 2004. We analyzed data collected during initial visits to our AFC from 2004-2008 to determine the gender and racial characteristics of a tertiary AFC population. Multivariable regression analysis was used to compare clinical characteristics. There were a total of 1664 consecutive initial patient visits. Cardiologists referred 61% and primary care physicians referred 37% of patients. Twice as many men were referred as women (570 vs. 1094; P< 0.0001). Women were older (68.0+11.9 vs. 62.4+13.0 years; P< 0.0001) and more symptomatic with palpitations (80% vs. 73%; P=0.008), but otherwise were not substantially different from men. Both men and women were aggressively treated with anticoagulation and rate-controlling medications by our referring physicians. Minority patients were infrequently referred, with only 46 African American patients in the total population. In conclusion, the demographics of a tertiary FAC are different than those of the general population. Women and racial minority patients are underrepresented, and the women have few comorbidities and symptoms than the known epidemiology would lead us to expect.

Reducing Ionizing Radiation Associated with Atrial Fibrillation Ablation

Citation : Nisha L. Bhatia, Arshad Jahangir, William Pavlicek, Luis R.P. Scott, Gregory T. Altemose, Komandoor Srivathsan.Reducing Ionizing Radiation Associated with Atrial Fibrillation Ablation .JAFIB.2010 December;Volume 2 Issue(3): 822-826.

While radiation exposure with cardiac interventional procedures is an emerging concern, patients undergoing radiofrequency ablation (RFA) for atrial fibrillation (AF) still routinely undergo pre- and post-ablation computed tomography (CT) scans for 1) definition of left atrial and pulmonary vein anatomy, 2) creation of a surrogate geometry, and 3) assessment for complications such as pulmonary vein (PV) stenosis. In an effort to decrease ionizing radiation associated with atrial fibrillation ablation, an ultrasound-guided surrogate geometry approach is proposed as an alternative to routine CT imaging. Ten patients underwent AF ablation using intracardiac ultrasound for the creation of a surrogate left atrial geometry (CartoSound, Biosense Webster, CA); and ten control-cases who had conventional CT-guided imaging (CartoMerge, Biosense Webster, CA) were matched for age, gender, and type of catheter ablation. Sources of radiation included 1) intraprocedural fluoroscopy (CartoSound: 151 ± 43 mGray*cm^2, CartoMerge: 174 ± 130 mGray*cm^2; p=0.6) and 2) CT ionizing radiation (CartoSound: 0 mSv, CartoMerge 9.4 ± 2.3 mSv/CT scan.) When comparing clinical success rates after a trial of previously ineffective anti-arrhythmic drugs, ultrasound-guided AF ablation was non-inferior to a CT-guided approach, and obviated the need for CT imaging, therefore reducing doses of ionizing radiation by nearly 20 mSv per AF catheter ablation.

Left Atrial Volume and Post-Operative Atrial Fibrillation after Aortic Valve Replacement

Citation : Yeruva Madhu Reddy, Ruby Satpathy, Xuedong Shen, Mark Holmberg, Claire Hunter, Aryan Mooss, Dennis Esterbrooks.Left Atrial Volume and Post-Operative Atrial Fibrillation after Aortic Valve Replacement .JAFIB.2010 December;Volume 2 Issue(3): 814-821.

Post-operative atrial fibrillation (POAF) after valve surgery is associated with increased morbidity and mortality. Risk factors identified in the past to predict POAF are of moderate accuracy. We performed a retrospective analysis of 139 patients undergoing aortic valve replacement for aortic stenosis. Post-operative AF occurred in 44% of the patients. In multivariate analysis only left atrial volume (LAV) index was a predictor of POAF. A LAV index of >46 cc/m2 predicted POAF with a sensitivity and specificity of 92% and 77%. We propose that LAV index can be used preoperatively to identify patients at risk for POAF to target preventive interventions.