Catheter ablation of atrial fibrillation in patients with mechanical mitral valve: long-term outcome of single procedure of pulmonary vein antrum isolation with or without nonpulmonary vein trigger ablation.

INTRODUCTION: It is unclear whether extended pulmonary vein antrum isolation (PVAI) plus nonpulmonary vein (non-PV) trigger elimination prevents more arrhythmia recurrence than PVAI alone in patients with mechanical mitral valve (MMV) undergoing AF ablation. This study compared the efficacy and long-term outcome of 2 ablation strategies--PVAI alone versus extended PVAI plus non-PV trigger elimination--for the treatment of AF in patients with MMV. METHODS AND RESULTS: One hundred and nine consecutive AF patients with MMV were divided into 2 groups: standard PVAI was performed in group 1 (N = 45); in group 2 (N = 64) PVAI was extended to the LA posterior wall, LA septum, and CS; and all non-PV triggers were eliminated. Patients were followed up for 3 years. At the 12th month, 7 (15.6%) patients in group 1, and 39 (60.9%) patients in group 2 were arrhythmia free (log-rank P < 0.001). Four patients (8.9%; 3 cases of AT and 1 case of AF) from group 1, and 12 patients (18.8%; 9 cases of AT, and 3 cases of AFL) from group 2 experienced very late recurrence. At 36 ± 7 months follow-up, the cumulative recurrence after a single procedure was 42/45 (93.3%) in group 1, and 37/64 (57.8%) in group 2 (log-rank P < 0.001). CONCLUSION: Compared with the standard PVAI alone, a strategy including extended PVAI and non-PV trigger elimination is associated with a higher 12-month and long-term arrhythmia-free survival in patients with MMV undergoing AF ablation. Very late recurrence may occur years after the initial procedure with focal AT as the most common type of recurrent arrhythmia.

Variant rs2200733 on chromosome 4q25 confers increased risk of atrial fibrillation: evidence from a meta-analysis.

INTRODUCTION: Several genome-wide association studies have identified rs2200733, a single-nucleotide polymorphism (SNP) at 4q25 to be the most common chromosomal variant present in patients with atrial fibrillation (AF). We aimed to explore the association of rs2200733 with AF through a systematic review and meta-analysis. METHOD: An extensive literature search was performed on PubMed, and other databases using the key words "genetics" and "AF." Seven case-control studies evaluating the association via multivariate analysis were identified including a total of 83,335 subjects (10,546 with AF, 72,789 referent individuals without AF). Meta-analytic estimates were derived using random effects models. Potential sources of heterogeneity were examined in sensitivity analyses, and publication biases were estimated. RESULT: At pooled analysis, there was a strong independent association between the variant rs2200733 and the risk of AF (OR 1.89 [95% CI 1.62-2.16], P < 0.001). Minor allelic frequencies for SNP rs22000733 were significantly more prevalent in AF population than non-AF. Metaregression results revealed that country of descent (logOR 0.38, P = 0.45) or site of study (logOR: -0.16, P = 0.41) did not moderate the overall effect size. CONCLUSION: Variant rs2200733 on chromosome 4q25 independently confers increased risk of AF. This finding will aid in improving our understanding of AF pathophysiology, risk prediction, and stratification of treatment strategy.

Efficacy of catheter ablation in nonparoxysmal atrial fibrillation patients with severe enlarged left atrium and its impact on left atrial structural remodeling.

INTRODUCTION: The effect of catheter ablation on severe left atrial enlargement especially in nonparoxysmal atrial fibrillation (NPAF) patients is not well understood. Whether reverse remodelling may occur after ablation has not been evaluated in this setting. METHODS AND RESULTS: Fifty consecutive patients with left atrial diameter (LAD) ≥50 mm, and LA volume >200 cc undergoing catheter ablation for drug-refractory NPAF were included in this study. Transthoracic echocardiographic measurements were performed at baseline and at 12-months postprocedure. Left ventricular end-diastolic and end-systolic dimensions were indexed by body surface area (LVEDDI, LVESDI). Electroanatomic mapping system (Carto or NavX system) and computed tomography (CT) were used for 3-dimensional reconstruction of the LA. All patients underwent posterior wall isolation and pulmonary vein (PV) antrum and extra PV trigger ablations. Long-term follow-up was monitored by event recordings, 7-day Holter monitors and office visits. The mean age was 65 ± 10 years, 78% male, persistent AF 22 (44%), longstanding AF 28 (56%), LAD diameter 56.9 ± 7.8 mm, left ventricular ejection fraction (LVEF) 53 ± 14 and median AF duration 72 (49-96) months. At 12-month follow-up, 27 patients (54%) remained arrhythmia-free off antiarrhythmic drugs. Significant reduction in LAD at follow-up (≥10% reduction) was observed in 52% (26/50) of the total population and among the 63% (17/27) of recurrence-free patients. Magnitude of LA reduction was identically distributed among the persistent and longstanding persistent AF cohorts (16 ± 12% vs 14 ± 16%, respectively, P = 0.15). A significant 20% improvement in LVEF (from 53 ± 14 to 58 ± 9, P = 0.03) was found in the overall population. Improvement was noted in recurrence-free patients. No significant change in LVEDDI and LVESDI was noted. After adjusting for baseline risk factors in a multivariable model, a reduction in LAD was identified as a strong predictor of long-term success (beta = -11.1, P = 0.013). Preexisting LA scarring was associated with increased LAD (beta = 2.7, P = 0.023). No periprocedural or long-term complications were reported. CONCLUSION: Our results show that atrial fibrillation ablation is effective in NPAF patients with severe LA enlargement and is associated with LA reverse remodeling and improvement in LVEF.

Intraprocedural and long-term incomplete occlusion of the left atrial appendage following placement of the WATCHMAN device: a single center experience.

INTRODUCTION: Transcatheter left atrial appendage (LAA) closure with the WATCHMAN device has become one of the therapeutic options in atrial fibrillation (AF) patients who are at high risk for ischemic stroke. However, the incidence and evolution of incomplete occlusion of the LAA during and after placement of the WATCHMAN device has not been reported. METHODS AND RESULTS: Fifty-eight consecutive patients who had undergone WATCHMAN device implant were included in the study. Intraprocedural, 45-day and 12-month transesophageal echocardiogram images were reviewed and analyzed. Peridevice gap was noted in 16 (27.6%), 17 (29.3%), and 20 (34.5%) patients across the 3 time points. Intraprocedural gaps are more likely to be persistent until 12 months and become larger in size over time. New gap also occurs during follow-up even if the LAA was completely sealed at implantation. One patient had an ischemic stroke 4.7 months after implant; another patient developed a left atrial thrombus over the device 21.6 months after implant. Both patients had intraprocedural gap and discontinued warfarin therapy after the 45-day evaluation. CONCLUSION: Incomplete LAA occlusion with a gap between the WATCHMAN device surface and the LAA wall is relatively common. Intraprocedural gaps are more likely to become bigger over time and persist, while new gaps also occur during follow-up. Further studies are warranted to verify whether the presence and persistence of a peridevice gap is associated with increased risk of thromboembolic event in AF patients implanted with a WATCHMAN device.

Catheter ablation of atrial fibrillation in octogenarians: safety and outcomes.

INTRODUCTION: Radiofrequency catheter ablation (RFCA) is an effective treatment for atrial fibrillation (AF), although studies evaluating the role of RFCA have largely excluded elderly patients. We report the safety and outcomes of RFCA of AF in octogenarians. METHODS AND RESULTS: From 2008 to 2011, out of 2,754 consecutive patients undergoing RFCA of AF, 103 (3.7%) had ≥80 years (age 85 ± 3 years, 4 with >90 years). Pulmonary vein (PV) antrum isolation was performed in paroxysmal AF. In nonparoxysmal AF, ablation was extended to the entire left atrial posterior wall and to complex fractionated electrograms. Non-PV triggers were disclosed by isoproterenol challenge at the end of the procedure and targeted for ablation. Octogenarians presented a high rate of non-PV triggers (84% vs 69%, P = 0.001), especially in patients with paroxysmal AF (62% vs 19%, P < 0.001); non-PV triggers were most commonly mapped in the coronary sinus (54%), left atrial appendage (32%), interatrial septum and superior vena cava (14%). After a mean follow-up of 18 ± 6 months, 71 (69%) octogenarians remained free from AF recurrence off antiarrhythmic drugs after a single procedure (vs 71% in patients <80 years, P = 0.65). The success rate reached 87% after 2 procedures. Total periprocedural complication rates also did not differ between the 2 age groups. CONCLUSIONS: RFCA of AF is safe and effective in octogenarians. A high rate of non-PV triggers is present in these patients, and targeting multiple structures other than the pulmonary veins is often necessary to achieve long-term success.

Catheter ablation of atrial fibrillation in hypertrophic cardiomyopathy: long-term outcomes and mechanisms of arrhythmia recurrence.

BACKGROUND: Pulmonary vein (PV) antrum isolation in patients with hypertrophic cardiomyopathy and atrial fibrillation (AF) has been reported to have satisfactory results at the mid- and short-term follow-up. We determined the outcomes at the long-term follow-up of PV antrum isolation in these patients. METHODS AND RESULTS: We enrolled 43 patients with hypertrophic cardiomyopathy and AF (28% paroxysmal AF). PV antrum isolation (paroxysmal AF) and posterior wall isolation with complex fractionated atrial electrogram ablation (persistent and longstanding persistent AF) were the end points at the time of the index procedure and for repeat procedures during the first year of follow-up. In case of recurrent arrhythmia >1 year, high-dose isoproterenol challenge was used to disclose non-PV trigger sites. During the first year, the success rate reached 91% (mean of 1.6 procedures). After a median follow-up of 42 months (range, 38-48 months), 49% of the patients remained free from AF/atrial tachycardia. All patients underwent an additional procedure. PV antrum and posterior wall remained isolated in 82% of the cases, and extra-PV triggers were documented in all patients and targeted for ablation. After a median follow-up of 15 months (range, 8-19 months) subsequent to the last procedure, 94% of the patients remained free from AF/atrial tachycardia off antiarrhythmic drugs. CONCLUSIONS: PV isolation in patients with hypertrophic cardiomyopathy is feasible and safe, although is not effective in preventing late (≥1 year) AF recurrences in ≈50% of patients. Non-PV triggers seem to be responsible of late recurrences, which supports the appropriateness of a more extensive ablation beyond PV isolation to improve the long-term arrhythmia-free survival.

Examining the safety of amiodarone.

INTRODUCTION: Amiodarone is the most widely used antiarrhythmic agent, with demonstrated effectiveness against all the spectrum of cardiac tachyarrhythmias. The risk of adverse effects acts as a limiting factor to its utilization especially in the long term. This article systematically reviews the published evidence on amiodarone versus placebo to examine its safety as an antiarrhythmic drug. AREAS COVERED: Authors collected data on adverse effects reported in 49 randomized placebo-controlled trials with amiodarone. Adverse effects were classified according to the organ/system involved. Pooled estimates of the number needed to treat (NNT) and to harm (NNH) versus placebo were calculated. EXPERT OPINION: Amiodarone is effective for both the acute conversion of atrial fibrillation (AF) (11 trials, NNT = 4 at 24 h; p = 0.003) and the prevention of postoperative AF (18 trials, NNT = 8; p < 0.001), although with an increased risk of bradycardia, hypotension, nausea or phlebitis (pooled NNH = 4; p < 0.001). Amiodarone administration for the maintenance of sinus rhythm has a favorable net clinical benefit (pooled NNT = 3; p < 0.001 versus pooled NNH for either thyroid toxicity, gastrointestinal discomfort, skin toxicity or eye toxicity = 11; p < 0.001). Treatment with amiodarone for the prophylaxis of sudden cardiac death has less favorable net clinical benefit (15 trials, NNT = 38; p < 0.001 versus NNH for either thyroid toxicity, hepatic toxicity, pulmonary toxicity or bradycardia = 14; p < 0.001). Amiodarone treatment in this setting should be used in only selected cases.

Quality of life and patient-centered outcomes following atrial fibrillation ablation: short- and long-term perspectives to improving care.

Catheter ablation of atrial fibrillation (AF) has evolved as a potential curative option for drug-refractory AF in recent years. AF not only causes physical morbidity but also jeopardizes the mental and social health of the patient as well as predisposing the patient to increased risk of thromboembolic events. Therefore, the primary end points of AF ablation have been restoration of sinus rhythm, improvement in the quality of life and lowering the risk of cerebrovascular accidents. However, even in the best hands, AF ablation is yet to be a total success. Several risk factors of AF and parameters of catheter ablation influence the short- and long-term ablation outcome. This article reviews all the information that has been contributed by prominent independent researchers over the last decade.

Ablation for Atrial Fibrillation: Termination of Atrial Fibrillation is Not the End Point.

Permanent pulmonary vein isolation constitutes the main procedural goal of current approaches to atrial fibrillation (AF) catheter ablation, with established effectiveness as a stand-alone procedure in most patients with paroxysmal AF. In patients with AF of longer duration, however, the definition of the optimal procedural end point is still controversial. Based on analysis of data from 16 studies that have assessed the value of AF termination in predicting long-term procedural success, it is concluded that AF termination clearly represents an unreliable procedural end point during ablation of nonparoxysmal AF.

Catheter ablation of atrial fibrillation: state-of-the-art techniques and future perspectives.

The impact of atrial fibrillation on the healthcare systems of Western countries is overwhelming, due to its independent association with death, systemic thromboembolism, impaired quality of life and hospitalizations. Catheter ablation is the only treatment thus far demonstrated capable of achieving cure in a substantial proportion of patients. Pulmonary vein antrum isolation (PVAI) is the cornerstone of current atrial fibrillation ablation techniques, with the greatest efficacy as a stand-alone procedure in patients with paroxysmal atrial fibrillation. Use of general anesthesia, open-irrigated ablation catheters and maintenance of periprocedural therapeutic warfarin has been demonstrated to increase the safety and effectiveness of PVAI. In patients with paroxysmal atrial fibrillation, the systematic addition of superior vena cava isolation increases the long-term freedom from atrial fibrillation recurrence. A more extensive ablation approach extending to the entire left atrial posterior wall and to complex fractionated electrograms (CFAEs) is warranted in nonparoxysmal atrial fibrillation patients, in whom nonpulmonary vein trigger sites are frequently identified. Up to one-third of these patients experiencing atrial fibrillation recurrence after ablation have evidence of triggers from the left atrial appendage. Isolation of this structure is the best treatment strategy to improve the long-term success rate. In recent years, in addition to the development of ablation techniques to increase the success rate, outcomes of atrial fibrillation treatment trials have been reconsidered. In particular, reduction of hospitalization, stroke and mortality, as well as economic factors, have all been considered relevant to evaluate the effectiveness of atrial fibrillation treatment. Large ongoing trials are specifically evaluating the impact of atrial fibrillation ablation on these outcomes. This article will summarize the state-of-the art techniques for atrial fibrillation ablation, and will discuss the contribution of ongoing studies to the future of atrial fibrillation ablation.

Impact of metabolic syndrome on procedural outcomes in patients with atrial fibrillation undergoing catheter ablation.

OBJECTIVES: The aim of this study was to investigate impact of metabolic syndrome (MS) on outcomes of catheter ablation in patients with atrial fibrillation (AF) in terms of recurrence and quality of life (QoL). BACKGROUND: MS, a proinflammatory state with hypertension, diabetes, dyslipidemia, and obesity, is presumed to be a close associate of AF. METHODS: In this prospective study, 1,496 consecutive patients with AF undergoing first ablation (29% with paroxysmal AF, 26% with persistent AF, and 45% with long-standing persistent AF) were classified into those with MS (group 1; n = 485) and those without MS (group 2; n = 1,011). Patients were followed for recurrence and QoL. The Medical Outcomes Study SF-36 Health Survey was used to assess QoL at baseline and 12 month after ablation. RESULTS: After 21 ± 7 months of follow-up, 189 patients in group 1 (39%) and 319 in group 2 (32%) had arrhythmia recurrence (p = 0.005). When stratified by AF type, patients with nonparoxysmal AF in group 1 failed more frequently compared with those in group 2 (150 [46%] vs. 257 [35%], p = 0.002); no difference existed in the subgroup with paroxysmal AF (39 [25%] vs. 62 [22%], p = 0.295). Group 1 patients had significantly lower baseline scores on all SF-36 Health Survey subscales. At follow-up, both mental component summary (Δ5.7 ± 2.5, p < 0.001) and physical component summary (Δ9.1 ± 3.7, p < 0.001) scores improved in group 1, whereas only mental component summary scores (Δ4.6 ± 2.8, p = 0.036) were improved in group 2. In the subgroup with nonparoxysmal AF, MS, sex, C-reactive protein ≥0.9 mg/dl, and white blood cell count were independent predictors of recurrence. CONCLUSIONS: Baseline inflammatory markers and the presence of MS predicted higher recurrence after single-catheter ablation only in patients with nonparoxysmal AF. Additionally, significant improvements in QoL were observed in the post-ablation MS population.

Ablation as First-Line Therapy for Atrial Fibrillation: Yes.

This article addresses the use of catheter ablation (CA) as first-line therapy for atrial fibrillation (AF). CA increases long-term freedom from AF, reduces hospitalizations, and improves quality of life compared with antiarrhythmic drug (AAD) therapy in patients with symptomatic AF who have already failed one AAD. The role of CA as first-line therapy for AF, however, is still controversial. Evidence from randomized controlled trials shows that CA is definitely superior to AADs as first-line therapy for relatively young patients with paroxysmal AF, with comparable complication rates and results consistently reproducible across different institutions, operators, and types of ablation approaches.

Atrial fibrillation and the risk of incident dementia: a meta-analysis.

BACKGROUND: The risk of cerebrovascular embolic events with atrial fibrillation (AF) is potentially linked to an increased risk of cognitive decline and dementia. However, epidemiologic studies exploring the association between AF and incident dementia have reported conflicting results. OBJECTIVE: The purpose of this study was to perform a meta-analysis of observational studies specifically designed to evaluate the prospective relationship between AF and incident dementia. METHODS: We searched PubMed, CENTRAL, BioMedCentral, Embase, Cardiosource, clinicaltrials.gov, and ISI Web of Science (January 1980 to May 2012). No language restriction was applied. Two independent reviewers screened titles and abstracts to identify population-based studies that prospectively evaluated the association between AF and the incidence of dementia in patients not suffering an acute stroke and with normal cognitive function at baseline, providing the hazard ratio (HR) obtained in multiple Cox regression analyses, and adjusted for all confounding variables. Two independent reviewers assessed risk of bias according to the Cochrane Collaboration, and extracted patient and study characteristics and the adjusted HR of incident dementia with its 95% confidence interval (CI) of patients with AF vs those without AF. RESULTS: Eight studies with 77,668 patients were included in the analysis. All studies had a prospective observational design and included elderly patients (mean age range 61-84 years) with normal cognitive function at baseline, of whom 11,700 (15%) had AF. After a mean follow-up of 7.7 ± 9.1 years (range 1.8-30 years), 4773 of 73,321 (6.5%) patients developed dementia. Two studies did not report the rates of dementia at follow-up but reported the adjusted HR and were included in the pooled analysis. At pooled analysis adjusted for baseline confounders and covariates, AF was independently associated with increased risk of incident dementia (HR = 1.42 [95% CI 1.17-1.72], P <.001). CONCLUSION: AF is independently associated with increased risk of dementia. Patients with AF should be periodically screened for dementia, which should be included among the outcomes assessed in AF treatment trials.

Endo-epicardial homogenization of the scar versus limited substrate ablation for the treatment of electrical storms in patients with ischemic cardiomyopathy.

OBJECTIVES: This study investigated the impact on recurrences of 2 different substrate approaches for the treatment of these arrhythmias. BACKGROUND: Catheter ablation of electrical storms (ES) for ventricular arrhythmias (VAs) has shown moderate long-term efficacy in patients with ischemic cardiomyopathy. METHODS: Ninety-two consecutive patients (81% male, age 62 ± 13 years) with ischemic cardiomyopathy and ES underwent catheter ablation. Patients were treated either by confining the radiofrequency lesions to the endocardial surface with limited substrate ablation (Group 1, n = 49) or underwent endocardial and epicardial ablation of abnormal potentials within the scar (homogenization of the scar, Group 2, n = 43). Epicardial access was obtained in all Group 2 patients, whereas epicardial ablation was performed in 33% (14) of these patients. RESULTS: Mean ejection fraction was 27 ± 5. During a mean follow-up of 25 ± 10 months, the VAs recurrence rate of any ventricular tachycardia (VTs) was 47% (23 of 49 patients) in Group 1 and 19% (8 of 43 patients) in Group 2 (log-rank p = 0.006). One patient in Group 1 and 1 patient in Group 2 died at follow-up for noncardiac reasons. CONCLUSIONS: Our study demonstrates that ablation using endo-epicardial homogenization of the scar significantly increases freedom from VAs in ischemic cardiomyopathy patients.

Does the left atrial appendage morphology correlate with the risk of stroke in patients with atrial fibrillation? Results from a multicenter study.

OBJECTIVES: This study investigated the left atrial appendage (LAA) by computed tomography (CT) and magnetic resonance imaging (MRI) to categorize different LAA morphologies and to correlate the morphology with the history of stroke/transient ischemic attack (TIA). BACKGROUND: LAA represents one of the major sources of cardiac thrombus formation responsible for TIA/stroke in patients with atrial fibrillation (AF). METHODS: We studied 932 patients with drug-refractory AF who were planning to undergo catheter ablation. All patients underwent cardiac CT or MRI of the LAA and were screened for history of TIA/stroke. Four different morphologies were used to categorize LAA: Cactus, Chicken Wing, Windsock, and Cauliflower. RESULTS: CT scans of 499 patients and MRI scans of 433 patients were analyzed (age 59 ± 10 years, 79% were male, and 14% had CHADS(2) [Congestive heart failure, hypertension, Age >75, Diabetes mellitus, and prior stroke or transient ischemic attack] score ≥2). The distribution of different LAA morphologies was Cactus (278 [30%]), Chicken Wing (451 [48%]), Windsock (179 [19%]), and Cauliflower (24 [3%]). Of the 932 patients, 78 (8%) had a history of ischemic stroke or TIA. The prevalence of pre-procedure stroke/TIA in Cactus, Chicken Wing, Windsock, and Cauliflower morphologies was 12%, 4%, 10%, and 18%, respectively (p = 0.003). After controlling for CHADS2 score, gender, and AF types in a multivariable logistic model, Chicken Wing morphology was found to be 79% less likely to have a stroke/TIA history (odd ratio: 0.21, 95% confidence interval: 0.05 to 0.91, p = 0.036). In a separate multivariate model, we entered Chicken Wing as the reference group and assessed the likelihood of stroke in other groups in relation to reference. Compared with chicken wing, cactus was 4.08 times (p = 0.046), Windsock was 4.5 times (p = 0.038), and Cauliflower was 8.0 times (p = 0.056) more likely to have had a stroke/TIA. CONCLUSIONS: Patients with Chicken Wing LAA morphology are less likely to have an embolic event even after controlling for comorbidities and CHADS2 score. If confirmed, these results could have a relevant impact on the anticoagulation management of patients with a low-intermediate risk for stroke/TIA.