This manuscript is a case report documented by a detailed patient log, that demonstrates efficacy of ranolazine for the management of paroxysmal atrial fibrillation that was progressive and resistant to prior antiarrhythmic drug therapy.
Sunday, October 31, 2010
The Power of One: a Highly Detailed, Log-Based, Case Example that Clearly Demonstrates the Effective Use of Ranolazine for the Control of Progressive
This manuscript is a case report documented by a detailed patient log, that demonstrates efficacy of ranolazine for the management of paroxysmal atrial fibrillation that was progressive and resistant to prior antiarrhythmic drug therapy.
To prevent recurrence of paroxysmal atrial fibrillation (AF, events < 7 days) isolation of pulmonary vein (PV) triggers results in success rates of up to 0.9 (i.e. 90%). Recent evidence suggests that complete circumferential antral ablation is not even necessary for PV isolation. When AF persists beyond one week, electrical and anatomic substrate remodeling typically occurs. Initially, when remodeling is slight, the arrhythmia can be terminated by PV isolation with only a few left atrial ablation lesions required in addition. However if longstanding persistent atrial fibrillation is present (defined as event duration > 6 months4 or > 1 year) greater left atrial substrate modification is necessary
Commentary on: Pericardial Fat is Independently Associated with Human Atrial Fibrillation by Al Chekakie et al.
Obesity is an established risk factor for atrial fibrillation (AF). In fact, it has been reported that the increasing prevalence of obesity in the United States could account for up to 60 % of the increasing incidence of age and sex adjusted AF. Adipose tissue has been shown to be highly metabolically active and secretes several proinflammatory mediators; however, different fat depots differ in metabolic and inflammatory activity.
The discovery of the role of the pulmonary veins (PVs) in atrial fibrillation (AF) has facilitated us to perform an anatomy-based ablation, “PV isolation”. Although several new mapping technologies have been developed, activation mapping during ongoing AF is still challenging. To improve the efficacy of AF ablation, therefore, we attempted to find the second “hot spot”. The superior vena cava, ligament of Marshall, coronary sinus and posterior LA have been reported as second critical areas for AF ablation. However, there remain patients who are refractory to catheter ablation targeting all of those above areas.
Non-valvular atrial fibrillation has been shown to be the most common cardiac arrhythmia with a growing world-wide incidence and a profound, better understood associated morbidity and mortality, most notably with cardioembolic strokes. This brief review highlights the risk of stroke and important studies of the latest treatment modalities available for stroke prevention in patients with non-valvular atrial fibrillation.
Pregnancy is accompanied by a variety of cardiovascular changes in normal women; all of these changes are thought to promote arrhythmogenesis. Atrial fibrillation is unusual during pregnancy and it can represent a benign, self-limited lone atrial fibrillation or can be hemodynamically significant in parturient with or without structural heart disease. Management of atrial fibrillation should be the same as in non-pregnant women, but requires faster intervention, even in patients with a normal heart function, and cautious use of medication to avoid harm to the fetus. We might remember that synchronized electrical cardioversion has been performed safely during all stages of pregnancy.
Atrial Tachycardias Occurring After Atrial Fibrillation Ablation: Strategies for Mapping and Ablation
The occurrence of left atrial tachycardias (AT) after catheter ablation for atrial fibrillation (AF) are common, especially after more extensive ablation of persistent AF. These AT are invariably symptomatic and often do not respond to medical therapy. The initial strategy involves ventricular rate control, cardioversion, and observation as some tachycardias may resolve with time. For persistent ATs, effective management frequently requires catheter intervention. Careful characterization of the tachycardia mechanism is essential in designing an effective ablation strategy that would also avoid further creation of pro-arrhythmic substrate. With this review, we summarize the incidence, mechanism, diagnosis and treatment of ATs occurring after AF ablation.
Atrial fibrillation (AF) is the most common cardiac rhythm disorder in clinical practice, with an estimated prevalence of 0.4% to 1% in the general population, increasing with age to 8% in those older than 80 years. The recognized risk factors for developing AF include age, hypertension, structural heart disease, diabetes mellitus, and hyperthyroidism. However, the etiology remains unclear in a significant number of patients younger than age 60 in whom no cardiovascular disease or any other known causal factor is present. This condition is termed lone AF, and may be responsible for as many as 30% of patients with paroxysmal AF seeking medical attention. Although regular physical activity clearly reduces cardiovascular morbidity risk, in recent years long-term endurance sport practice has been recognized as a risk factor for AF. However, the underlying mechanism explaining this association is unclear.
Angiotensin Receptor Blockers for the Prevention of Atrial Fibrillation Recurrences: Unending Hot Debate
Although there is a plausible scientific basis for the notion that inhibition of the renin-angiotensin system can reduce the incidence of atrial fibrillation (AF) the greatest benefit was seen in patients with heart failure/left ventricular dysfunction in whom therapy with an angiotensin converting enzyme (ACE) inhibitor or angiotensin receptor blockers (ARBs) is probably already indicated. A number of initial studies suggested that ACE inhibitors and ARBs might prevent new onset and recurrent AF. However, the available data do not support the use of these drugs solely for the prevention of AF. I believe that additional prospective definitive trials are needed to clarify the role of ARBs in the prevention of AF recurrence.
Effect of High-dose Telmisartan on the Prevention of Recurrent Atrial Fibrillation in Hypertensive Patients
Background: Telmisartan has been shown to exert an equivalent action as ramipril on the prevention of cardiovascular events, but the dose-dependent actions of telmisartan on the prevention of events remain unknown.
Objective: We investigated the dose-dependent effects of telmisartan on the prevention of AF in patients associated with risk factors.
Methods: One hundred hypertensive patients were randomized to take 40 mg (low-dose group: n=57) or 80 mg (high-dose group: n=43) of telmisartan for 24 months. The primary endpoints were defined as a new development and/or recurrence of atrial fibrillation (AF).
Results: The mean values of the blood pressure in both groups decreased significantly and to similar degrees after 24 months, in the low-dose (p < 0.01) and high-dose (p < 0.01) groups. At the end of the follow-up, the incidence of AF was lower in the high-dose group than in the low-dose group (p < 0.05). Moreover, the proportion of AF recurrences in the patients with a past history of paroxysmal AF was lower in the high-dose group than in the low-dose group (p < 0.05). Further, using a logistic regression model, there were no risk factors associated with the incidence of AF.
Conclusion: The results indicated that telmisartan in low doses was as effective in controlling the blood pressure as in high doses, but high doses of telmisartan had beneficial effects on preventing the recurrence of AF in hypertensive patients.
Thursday, September 2, 2010
Postural orthostatic tachycardia syndrome (POTS) is characterized by inappropriate increase in heart rate on assuming upright position from a supine position without a necessary drop in blood pressure. Etiology of this condition is complex and multifactorial. Autonomic dysfunction, hypovolemia, hyper responsiveness of beta adrenergic receptors with associated elevations of plasma norepinephrine levels have been implicated as underlying pathophysiologic mechanisms. Beta blockers have previously been used to treat this condition. Ivabradine which selectively inhibits If ion current in the sino atrial node, has been reported to be useful in patients with POTS. We present one further such case of POTS successfully treated by Ivabradine.
Stroke is a significant cause of mortality and disabling morbidity. The major subtypes of stroke are divided into thrombo-embolic, haemorrhagic and cryptogenic, with each having different predisposing risk factors and management strategies. Atrial fibrillation (AF) is the commonest arrhythmia predisposing to thrombo-embolic stroke. The incidence of AF increases with age, affecting up to 5% in the elderly population. Electrophysiology studies have implicated that spontaneous atrial ectopic beats that originate in or near pulmonary veins adjacent to the left atrium, may initiate paroxysms of AF.
Commentary on : New-Onset Atrial Fibrillation Predicts Long-Term Mortality After Coronary Artery Bypass Graft by El-chami et.al
El-Chami and colleagues report that new-onset post-operative atrial fibrillation (AF) is associated with a significant reduction in long-term survival (adjusted hazard ratio: 1.21; 95% confidence interval: 1.12 to 1.32; follow-up: mean 6 years, range: 0 to 12.5 years) for patients undergoing isolated coronary artery bypass grafting (CABG). Moreover, the authors suggest that patients with new-onset post-CABG AF discharged on warfarin experienced reduced mortality during follow-up (adjusted HR: 0.78, 95% CI: 0.66 to 0.92) when compared to those who were not discharged on warfarin.
The use of catheter ablation to treat AF is increasing rapidly, but there is presently an incomplete understanding of its cost-effectiveness. AF ablation procedures involve significant up-front expenditures, but multiple randomized trials have demonstrated that ablation is more effective than antiarrhythmic drugs at maintaining sinus rhythm in a second-line and possibly first-line rhythm control setting. Although truly long-term data are limited, ablation, as compared with antiarrrhythmic drugs, also appears associated with improved symptoms and quality of life and a reduction in downstream hospitalization and other health care resource utilization. Several groups have developed cost effectiveness models comparing AF ablation primarily to antiarrhythmic drugs and the model results suggest that ablation likely falls within the range generally accepted as cost-effective in developed nations. This paper will review available information on the cost-effectiveness of catheter ablation for the treatment of atrial fibrillation, and discuss continued areas of uncertainty where further research is required.
Atrial fibrillation (AF) is the most common arrhythmia encountered by caregivers for the elderly. A plethora of new, mostly invasive techniques have evolved to treat patients who remain symptomatic from this arrhythmia despite attempts at pharmacological therapy. The most widely-used of these new techniques is radiofrequency ablation, but in select patients, special types of pacemaker, cryoablation, and surgical maze therapy may be of benefit.
Several management options for patients with symptomatic atrial fibrillation (AF) available today were not even in the realm of discussion two decades ago. These advances, however, have primarily involved invasive management options for patients with drug refractory arrhythmia. After the recognition that electrical isolation of the thoracic veins benefits patients with paroxysmal AF, a slew of more involved ablative techniques evolved. Major breakthroughs in antiarrhythmic therapy, however, have not paralleled this meteoric development of invasive techniques. The drive for invasive procedures has, in fact, been widely based on the lack of availability of simple, effective, and safe pharmacological options for AF. The introduction of dronedarone into clinical practice represented a recent addition to antiarrhythmic therapy options for use in the management of patients with AF. This agent is an analogue of amiodarone but devoid of the iodine moiety which allows its use without the well-recognized and dreaded organ toxicity associated with long-term use. Nevertheless, a significant need exists for a drug with limited side effects that can be used for symptomatic intermittent AF without the need for daily chronic use, fear of organ toxicity, and concern regarding proarrhythmia in patients with structural heart disease.
The Conversion of Paroxysmal or Initial Onset Atrial Fibrillation with Oral Ranolazine: Implications for a New "Pill-In-Pocket" Approach in Structural
Background: The "Pill-in-Pocket" (PIP) is an approach to atrial fibrillation (AF) where oral anti-arrhythmics at 75% to 100% of the normal daily dose, given as a single dose, is used to convert recent-onset AF. Pro-arrhythmic risk has limited this approach to patients without structural heart disease (SHD). Ranolazine is an anti-anginal agent, which inhibits the abnormal late Na+ channel current resulting in decreased Na+/Ca++ overload. This inhibits after-depolarizations and reduces pulmonary vein firing, which have been implicated in the initiation and propagation of AF. Ranolazine increases atrial refractoriness and has no known pro-arrhythmic affects. Ranolazine is routinely given to patients with SHD. The ability of Ranolazine to terminate AF in man has not been described but if useful could be a safer PIP agent with application in the presence or absence of SHD. We describe our experience using oral Ranolazine to convert new or recurrent AF.
Method: 2000 mg of ranolazine was administered to 35 patients with new (16 patients) or recurrent (19 patients) AF of at least 3 but not greater than 48 hours duration. Clinical features, echocardiographic data, and SHD were noted. Success was defined as restoring sinus rhythm within 6 hours of Ranolazine.
Results: All but 4 patients had some form of SHD. Twenty-five patients were in the hospital, 5 were in the office, and 5 were at home at the time Ranolazine was administered. Twenty-five of 35 patients converted to sinus rhythm. No pro-arrhythmic effects, hemodynamic instability, adverse rate effects, or perceived intolerance were noted. The 71% conversion rate was comparable to other reported PIP protocols and much higher than reported placebo conversion rates.
Conclusion: High dose oral Ranolazine shows utility as a possible safe agent to convert new or recurrent AF. Larger placebo-controlled studies would appear to be warranted.
The optimal catheter ablation approach for long-standing persistent atrial fibrillation (AF) remains elusive despite significant advances made in our understanding of this arrhythmia. A recent systematic review highlighted the significant variation in procedural success rate both within and between techniques, necessitating repeat ablation procedures and anti-arrhythmic drugs to achieve improved outcomes in those with long-standing persistent AF. Indeed, current expert consensus statement recommended ablation beyond ostial pulmonary vein isolation for these patients.
Atrial Fibrillation Susceptibility Alleles on Chromosome 4q25 Modulate Response to Catheter Ablation
In the last five years, increasing evidence has emerged for a genetic predisposition to atrial fibrillation (AF). Framingham Heart Study investigators observed that the odds of developing AF were three times higher for individuals with at least one parent in whom AF was diagnosed before the age of 75 than in those without a parental history of AF. Similarly, in a large group of Icelanders, the risk of developing AF was increased nearly five-fold if one parent was affected before the age of 60. Furthermore, single rare genetic variants thought to be responsible for familial AF have been identified.
Is Isolation of Arrhythmogenic Pulmonary Veins Sufficient for the Long-term Efficacy of Atrial Fibrillation Ablation?
Atrial fibrillation (AF) is the commonest cardiac rhythm disorder, affecting about 5% of elderly patients. Despite the wide spread prevalence of AF, treatment options for the condition up until recently, were limited. Antiarrhythmic drug therapy which for a long time had been and to some extent still is the cornerstone for treating these patients, has shown a disappointing (£ 40%) efficacy for long-term maintenance of sinus rhythm. The seminal observations by Haissaguerre and colleagues demonstrating AF initiation from electrical depolarizations in the pulmonary veins (PV) and cure of AF in these patients by radiofrequency ablation (RFA) of the PV focus, has led to the emergence of percutaneous catheter based AF ablation. Since its original description in 1998, the AF ablation procedure has evolved considerably.
Ever since atrial fibrillation (AF) was first recognized in young people (so called “lone” AF) over 4 decades ago, there has been increasing focus on determining the underlying pathophysiology of condition. Although lone AF is presumed to be a highly heterogeneous disease, recent studies have identified novel risk factors such as inflammation, oxidative stress, endurance sports and genetics, for the arrhythmia. This monograph aims to highlight some of the recent advances in our understanding of the molecular pathophysiology of lone AF especially insight provided by contemporary genetic studies. These insights may provide novel therapeutic targets for treatment of this challenging arrhythmia in young patients.
The Utility of Ambulatory Electrocardiographic Monitoring for Detecting Silent Arrhythmias and Clarifying Symptom Mechanism in an Elderly Urban Popula
Background: Atrial and ventricular tachyarrhythmias, including atrial fibrillation (AF) as well as bradyarrhythmias have been well documented in elderly and generally symptomatic patients with heart failure (HF) and/or hypertension (HTN), most often using 24 hour continuous monitoring. However, the frequency of these arrhythmias, including silent as well as symptomatic, as assessed by more prolonged monitoring, the relationship between symptoms in patients with HF and/or HTN and an underlying arrhythmia, and the association of arrhythmias including those that are silent with subsequent cardiac events has not been well defined in patients 65 years or older with HF and other cardiovascular risk factors. Importantly in such patients, AF, even if symptomatic, would yield a CHADS2 score indicative of anticoagulation.
Objective: A pilot study to assess the potential value of 2 weeks of out-patient, transtelephonic cardiac auto-triggered loop-monitoring for detecting arrhythmias, assessing their relationship to symptoms, predicting the risk of subsequent cardiac events, and determining if they result in therapy in an elderly, urban population living with HF.
Methods: Fifty-four subjects with a history of systolic HF and/or HTN consented to wear an auto triggered cardiac loop monitor for 2 weeks. This device captures EKG data, including silent and symptomatic arrhythmias. Subjects were requested to transmit data once daily as well as to transmit if they were symptomatic to determine if an underlying dysrhythmia was present.
Results: Mean age was 73 ± 6 years with 59% were female, 74% Hispanic, 22% black, and 4% white/other. All subjects had HF and 94% had HTN; all were in sinus rhythm at the time of enrollment. From the cardiac monitoring, 72% demonstrated ectopic atrial and ventricular activity. In addition, 1 paroxysmal episode of AF was documented, 3 people had significant non-sustained ventricular tachycardia that contributed to the placement of an internal cardioverter defibrillator (ICD), and 4 individuals underwent subsequent placement of a pacemakers for severe bradycardia/heart block (per established guidelines). The relationship between arrhythmia and symptoms was weak. These events would have otherwise gone undetected and untreated. During follow-up, 15 subjects (28%) had significant cardiac events, including one patient with a non ST segment myocardial infarction (NSTEMI) infarct due to undetected and untreated AF and one patient with symptomatic 2:1 atrial flutter. The AF and flutter patients all had CHADS2 scores appropriate for initiation of anticoagulation.
Conclusion: A substantial proportion of subjects exhibited arrhythmias during monitoring, cardiac events during follow-up and consequent therapy. This approach to arrhythmia screening appears to have sufficient merit to warrant further study.
Introduction: Paroxysmal atrial fibrillation (PAF) is a common arrhythmia, and it is associated with various cardiac conditions. On the other hand, lone PAF has no identifiable underlying cause, and can occur any time for no apparent reason. The underlying causes may modify the electrophysiological properties of the atrium in different ways and extent. However this setting may be different in patients with lone PAF. We sought to investigate the atrial electrophysiological properties in lone PAF.
Material and Methods: This study included 62 control subjects (Control group) and 58 patients with lone PAF (LAF group). The following atrial vulnerability parameters induced by programmed atrial stimulation were assessed and quantitatively measured: 1) the atrial effective refractory period (ERP), 2) the atrial conduction delay (CD) zone, and 3) the maximum CD.
Results: The mean atrial ERP of the Control group was 215±29 ms, and that of LAF group was 208±28 ms, p<0.05. The mean atrial CD zone of the LAF group was (50±28 ms) significantly greater than that of controls (34±22 ms) (p<0.01). The mean maximum CD of the LAF group (62±29 ms) was also significantly greater than that of controls (43±20 ms) (p<0.01).
Conclusions: There is a greater conduction delay of the atrium and shorter refractoriness in patients with lone PAF. Patients without underlying causes for the development of PAF exhibit abnormalities in the electrophysiological properties of the atrium.
Key words: Atrial vulnerability. Atrial refractory period. Atrial conduction time. Atrial fibrillation. Atrial conduction delay.
Saturday, April 10, 2010
Determining esophageal anatomy with a new electroanatomical mapping system Short Title – Esophageal anatomy during PVI Diego Chemello MD, Imad Ham
A 53-year-old woman with symptomatic paroxysmal atrial fibrillation was referred for pulmonary vein isolation (PVI). After obtaining access to left atrium (LA) and placement of catheters by standard technique, a high-resolution electroanatomical map of the LA and the pulmonary veins (PVs) was constructed using a map catheter (EZ Steer® Bi-directional catheter, Biosense Webster, Inc. Diamond Bar, USA) and the Carto® 3 System (Biosense-Webster Inc. Diamond Bar, USA) in the Fast Anatomical Mapping (FAM) mode.
The ablation of atrial fibrillation (AF) is an area of intense research in cardiac electrophysiology. In this review, we discuss the development of catheter-based interventions for AF ablation. We outline the pathophysiologic and anatomic bases for ablative lesion sets and the evolution of various catheter designs for the delivery of radiofrequency (RF), cryothermal, and other ablative energy sources. The strengths and weaknesses of various specialized RF catheters and alternative energy systems are delineated, with respect to efficacy and patient safety.
Atrial fibrillation (AF) is the most commonly encountered arrhythmia in clinical practice but the mechanisms underlying the initiation and maintenance of AF are yet to be clarified. It is well-known that regular exercise is beneficial to health and reduces the risks of cardiovascular diseases. However, recent studies suggest that long-term endurance exercise, including running , swimming, rowing  and cycling , or vigorous competitive sports may increase the incidence of AF in these athletes. This review article is intended to provide a summary of the possible links between exercise and AF.
AF is a common arrhythmia associated with large burden of morbidity and mortality. In areas with a high prevalence of rheumatic heart disease, valve disease is the most common substrate for the occurrence of AF and this problem assumes greater importance because the resulting escalation in morbidity and mortality involves relatively younger population. As is true of the general population, the prevalence of AF in patients with rheumatic mitral valve disease (RMVD) increases with advancing age.
Background Postoperative occurrence of atrial ﬁbrillation (AF) has been associated with less favorable outcomes in patients undergoing cardiac surgery and may result in increased post-operative morbidity and mortality.
Objectives A systematic review and meta-analysis of published studies were conducted to verify the effect of statins in the occurrence of AF after cardiac surgery.
Methods Using the Medline database, the Cochrane clinical trials database and online clinical trial databases, we reviewed all randomized controlled trials (RCTs) and observational studies examining the risk factors of occurrence AF after CABG. We searched for literature published April 2009 or earlier.
Results Our review identified 6 studies (observational studies), involving 10165 patients, that examined the effect of statins on the occurrence of AF following cardiac surgery. Conflict from most of articles, the overall outcomes suggest that the statins group did not have a significant decrease in the occurrence of AF following cardiac surgery (P = 0.19).
Conclusions The preoperative medication of statins showed no significant decrease in AF occurrence following cardiac surgery in the Meta-analysis result. A more prospective studies and researches are needed to explore and demonstrate the real effect of statins on the postoperative AF.
Monday, January 11, 2010
Monomorphic Outflow Tract Ventricular Tachycardia: Unique Presenting Manifestation of Gitelman’s Syndrome
Outflow Tract Ventricular Tachycardia (OTVT) is typically seen in young to middle aged people with structurally normal hearts. These arrhythmias are triggered by emotional or stress factors and that responds to medications. Electrolyte abnormalities rarely cause ventricular arrhythmia. Gitelman’s syndrome, a rare autosomal recessive renal disorder causes hypokalemia, metabolic alkalosis and hypomagnesaemia. This disorder is often benign with mild clinical symptoms and excellent long-term prognosis. We present a case of Gitelman’s syndrome with symptomatic OTVT as initial manifestation.
Dabigatran, a direct thrombin inhibitor, in atrial fibrillation: Is it already time for a change in oral anticoagulation therapy?
Atrial fibrillation (AF) is a common arrhythmia, and its prevalence increases with aging and the severity of heart disease. AF affects more than 2 million people in the US, and more than 4 million in Europe. It is expected that the age adjusted prevalence in US will excede 10 million people by the year 2050 . In the last decade, we were able to see the light shed by several trials that dealt with AF mechanisms and the appropriate management of AF patients. Clinical studies have focused mainly on the electrophysiological properties of the substrate in the atrial muscle during sinus rhythm and on the atrial electrical responses elicited by premature stimulation method . However, many fundamental aspects of this arrhythmia have been poorly understood until quite recently, and there are several features on the mechanisms of AF that makes it difficult to manage it properly. Increasing awareness of AF as a disease with possible fatal complications rather than as an acceptable alternative to sinus rhythm has led to search for clear arguments to support a certain strategy as a gold standard.
Pulmonary vein stenosis is a rare but serious complication of pulmonary vein isolation to treat atrial fibrillation. Pulmonary vein angioplasty/stenting has emerged as the treatment of choice for significantly stenotic veins. Guidelines for post ablation evaluation of the pulmonary veins, including the timing and method of surveillance for possible stenosis, the criteria for intervention, the technical aspects of intervention, and finally the surveillance post intervention, are still being developed. The relatively high rate of restenosis after intervention in a subset of patients remains a great challenge. A better understanding of the pathophysiology underlying this syndrome is needed to appropriately answer many of the remaining questions. The goal of this manuscript is to describe what has been learned about this complication and its treatment from a relatively large experience in a single institution over the past decade, and provide a comprehensive review of the existing literature in order to shed as much light on the subject as is possible, while at the same time exposing the areas that need further study.
Ablative therapy for atrial fibrillation is becoming more commonplace, and some minimally symptomatic or asymptomatic patients will be referred for ablative therapy. Reasons to ablate asymptomatic patients include young age and/or the presence of a tachycardia induced cardiomyopathy; in addition, some symptomatic patients may become asymptomatic after ablation. Managing these patients can be challenging. In this review, we will discuss the use of telemetric monitoring, antiarrhythmic drugs and anticoagulation after ablation in asymptomatic patients with atrial fibrillation.
AAD - antiarrhythmic drugs
AF - atrial fibrillation
LVEF - left ventricular ejection fraction
TTM - transtelephonic monitor
There is increasing evidence linking C-reactive protein (CRP) and atrial fibrillation (AF). Despite the abundance of literature, confusion exists regarding this association because of inconsistent results. MEDLINE and Cochrane Controlled Trials Register databases were carefully searched through July, 2007 combining the following terms “C-reactive protein” and “atrial fibrillation”. Of the 106 studies initially identified, 7 studies with 7349 subjects (638 with AF) were included in the meta-analysis. Analysis yielded a relative risk of 1.51 (1.24, 1.84) for occurrence of AF when CRP level was above a cut off of 3-3.5 mg/l. When 2 studies with data on a higher cut off of 4.5-5.0 mg/l were analyzed separately, the relative risk was 4.03 (2.6, 6.2). Our study suggests that elevated CRP increases the relative risk for AF. The risk appears incremental with higher CRP levels conferring proportionately increased risk. There is an urgent need for further large scale well designed studies.
Background : Natriuretic peptide (NP) is high in atrial fibrillation (AF)and may decrease after cardioversion to sinus rhythm and the levels of atrial NP (ANP) and brain NP (BNP) in different types of AF and whether ANP and BNP have predictive values for relapsed AF have not been determined.
Purpose: We aimed to examine the levels of ANP and BNP in AF to determine their roles in different types of AF, including a predictive value in relapsed AF.
Methods and Results : ANP and BNP were measured in 100 consecutive patients with AF and without heart dysfunction at baseline and in 20 controls. All patients had higher levels than controls (p<0.01). After cardioversion treatment with antiarrhythmic therapy, 40 patients failed to cardiover cardioversion successfully and still showed AF, whereas 60 patients were successful. ANP and BNP levels decreased significantly after cardioversion (163.55±54.27pg/ml vs. 200.20±55.63 pg/ml; 124.15±43.00 pg/ml vs. 161.99±48.04 , for ANP and BNP respectively, both p<0.0001). 18 of the 60 successfully cardioverted patients had AF recurred within 24 hours, who were then excluded from 500-day follow-up and the remaining 42 patients were enrolled. During 500-day follow-up period, AF relapsed in 16 patients. Comparing with the 42 patients, the 16 patients showed higher concentrations of ANP (187.72±32.79 pg/ml vs. 138.42±30.65 pg/ml, p<0.0001). Besides, both ANP and BNP were significantly higher in the relapsed patients than those remained SR during follow-up (153.38±29.6 pg/ml vs. 129.21±27.98 pg/ml for ANP, p=0.01 and 147.41±25.95 pg/ml vs. 121.87±20.53pg/ml for BNP, p=0.001). The area under the receiver-operating characteristic curve was 0.799 for BNP and 0.706 for ANP in predicting a relapse of AF. Using the BNP optimized cut-off level of 138 pg/ml, relapsed AF can be predicted with relatively acceptable accuracy.
Conclusions : ANP and BNP decrease significantly after cardioversion in patients with AF, and both can be useful predictors of relapsed AF.
Key Words: Atrial fibrillation; ardioversion; ANP; BNP; relapse of atrial fibrillation