Catheter-based Atrial Fibrillation Ablation Research Articles

Use of a New Standardized Unfractionated Heparin Protocol for Left-Sided Ablation Procedures Improves Time in the Therapeutic ACT Range

Objectives: This study evaluated whether a novel standardized heparin dosing protocol used during atrial fibrillation catheter ablation resulted in a higher percentage of therapeutic activated clotting time (ACT) values compared to historic nonstandardized procedures. DesignA retrospective cohort study SettingThis study was conducted at Ochsner Medical Center, the largest tertiary care teaching hospital in New Orleans, LA ParticipantsPatients undergoing catheter-based atrial fibrillation ablation InterventionsWe implemented a standardized heparin protocol and enrolled patients between November 2020 and March 2021. The historic controls consisted of patients who underwent atrial fibrillation ablation between April 2020 and September 2020. Heparin administration in the control group was based on physician preference and was nonstandardized. Measurements and Main ResultsThe primary endpoint was the percentage of intraprocedural ACTs in therapeutic range (≥300 to <450 s). Secondary endpoints included first measured ACT at ≥300 s and percent of measured ACTs in the supratherapeutic range (>450 s). Comparisons were performed using chi-squared tests or Fisher exact tests. Patients in the intervention group had a higher mean percentage of ACTs in the therapeutic range compared to the control group (84.9% vs. 75.8%, p<0.001). More patients in the intervention group reached therapeutic ACT on the first measurement compared to the control group (70.3% vs. 31.2%, p<0.001). Conclusion: During catheter-based cardiac ablation procedures, a novel standardized unfractionated heparin dosing protocol resulted in a higher percentage of ACTs in the target range and a higher proportion of initial ACTs in the therapeutic range compared with baseline nonstandardized heparin dosing.

Catheter ablation of atrial fibrillation in hypertrophic cardiomyopathy: A proportional meta-analysis and systematic review of single-arm studies

Atrial fibrillation (AF) is the most common arrhythmia in patients with hypertrophic cardiomyopathy (HCM). Limited data exists about the efficacy and clinical outcomes of AF ablation in HCM. The purpose of this meta-analysis was to evaluate the role of catheter-based ablation for treatment of AF in patients with HCM. PubMed, SCOPUS, Web of Science, Embase, Cochrane library, and ClinicalTrials.gov were searched for studies discussing outcomes of catheter-based ablation for AF in patients with HCM. Two reviewers independently screened studies and extracted relevant data. Incidence rate estimates from individual studies underwent logit transformation to calculate the weighted summary proportion under the random effect model. A total of 19 reports met the inclusion criteria (1183 patients). The single ablation procedure was successful in 39% patients. Up to 34% patients underwent a repeat ablation. About 41% patients in normal sinus rhythm after successful AF ablation received postprocedure antiarrhythmic drug (AAD) therapy. Patients undergoing successful AF ablation experienced a significant improvement in the New York Heart Association functional class (standardized mean difference -1.03; 95% confidence interval -1.23 to -0.83; P < .00001). AF ablation appears to be safe and feasible in patients with HCM. Freedom from AF after undergoing successful ablation is associated with significant improvement in heart failure symptoms.

Impact of Catheter Ablation on Long-Term Outcomes in Patients With Atrial Fibrillation: A Meta-Analysis

The role of catheter ablation in patients with atrial fibrillation (AF) in enhancing long-term outcomes remains unknown. This meta-analysis aimed to assess the impact of catheter ablation on stroke, all-cause mortality, hospitalization due to heart failure, and major bleeding events in patients with atrial fibrillation. This meta-analysis was conducted in compliance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The data search was carried out by two authors independently using online databases including PubMed, EMBASE, and Cochrane library. The primary outcome was a stroke. The secondary outcomes were all-cause mortality, hospitalization for heart failure, and major bleeding events. Total, 10 articles were included in the current meta-analysis encompassing 275392 patients (33291 in the ablation group and 244974 in the non-ablation group). Among all included studies, one study was a randomized control trial, while the remaining other were retrospective cohorts. The current meta-analysis showed that catheter-based AF ablation reduced the risk of stroke (hazard ratio {HR}: 0.61, 95% CI: 0.49-0.77), all-cause mortality (HR: 0.60, 95% CI: 0.51-0.71), and hospitalization for heart failure (HR: 0.57, 95% CI: 0.43-0.76). No significant differences were reported in terms of major bleeding events between patients who received catheter-based AF ablation and patients who did not receive catheter-based AF ablation (HR: 0.96, 95% CI: 0.80-1.14). In the current meta-analysis, catheter-based AF ablation was associated with decreased risk of all-cause mortality, stroke, and hospitalization due to heart failure. However, no significant difference was reported in terms of major bleeding events.

Effects of hot balloon versus cryoballoon ablation for atrial fibrillation: a systematic review and meta-analysis

Abstract Funding Acknowledgements Type of funding sources: None. Background Catheter ablation has developed as the most effective therapeutic approach and won the highest-level guideline recommendation in treating atrial fibrillation (AF) in the decades. Several balloon-based catheter ablations, including hot balloon ablation (HBA) and cryoballoon ablation (CBA), have rapidly emerged as alternative modalities to conventional radiofrequency catheter-based AF ablation. However, the differences in characteristics, effectiveness, clinical outcomes, safety, and efficacy between HBA and CBA remain undetermined. Purpose To compare the differences in the prognosis and characteristics between HBA and CBA. Methods Our electronic search was conducted in six databases, including PubMed, Embase, Cochrane Library, Web of Science, ClinicalTrial.gov, and medRxiv, with specific search strategies. Eligible studies were selected according to specific criteria. All records were identified up to June 1, 2021. The mean difference, odds ratios (ORs), and 95% confidence interval (95% CI) were calculated to evaluate the clinical outcomes. Heterogeneity and risk of bias were also assessed with predefined criteria. Results A total of 7 studies were included in our final meta-analysis. Comparing with CBA, more patients in the HBA group required touch-up ablation (OR 2.76, 95% CI, 2.02, 3.77, P = 0.000). More residual conduction was seen in the HBA group. HBA group had a longer procedure duration than the CBA group (WMD 14.24, 95%CI 4.39, 24.09, P = 0.005). More patients in the CBA group were likely to have AF occurrence (OR 0.75, 95% CI, 0.44, 1.27, P = 0.281) and accepted more antiarrhythmic drug therapy (OR 0.70, 95% CI, 0.45, 1.09, P = 0.114), although the result was insignificant. Conclusions Both HBA and CBA are effective ablation approaches to treat atrial fibrillation. Patients who received HBA were more likely to receive touch-up ablation and undergo longer procedure time. Patients in the CBA group were more likely to have AF occurrence and accepted more antiarrhythmic therapies. However, the long-term safety is still unknown. Further studies of multicenter, randomized clinical trials are warranted to verify this fundamental question.

Atrial fibrillation and atrial cardiomyopathies.

Atrial fibrillation (AF) is the most common arrhythmia among adults. While there have been incredible advances in the management of AF and its clinical sequelae, investigation of atrial cardiomyopathies (ACMs) is becoming increasingly more prominent. ACM refers to the electromechanical changes-appreciated subclinically and/or clinically-that underlie atrial dysfunction and create an environment ripe for the development of clinically apparent AF. There are several subtypes of ACM, distinguished by histologic features. Recent progress in cardiovascular imaging, including echocardiography with speckle-tracking (e.g., strain analysis), cardiovascular magnetic resonance imaging (CMR), and atrial 4-D flow CMR, has enabled increased recognition of ACM. Identification of ACM and its features carry clinical implications, including elevating a patient's risk for development of AF, as well as associations with outcomes related to catheter-based and surgical AF ablation. In this review, we explore the definition and classifications of ACM, its complex relationship with clinical AF, imaging modalities, and clinical implications. We propose next steps for a more unified approach to ACM recognition that can direct further research into this complex field.

Ablation Modalities for Therapeutic Intervention in Arrhythmia-Related Cardiovascular Disease: Focus on Electroporation.

Targeted cellular ablation is being increasingly used in the treatment of arrhythmias and structural heart disease. Catheter-based ablation for atrial fibrillation (AF) is considered a safe and effective approach for patients who are medication refractory. Electroporation (EPo) employs electrical energy to disrupt cell membranes which has a minimally thermal effect. The nanopores that arise from EPo can be temporary or permanent. Reversible electroporation is transitory in nature and cell viability is maintained, whereas irreversible electroporation causes permanent pore formation, leading to loss of cellular homeostasis and cell death. Several studies report that EPo displays a degree of specificity in terms of the lethal threshold required to induce cell death in different tissues. However, significantly more research is required to scope the profile of EPo thresholds for specific cell types within complex tissues. Irreversible electroporation (IRE) as an ablative approach appears to overcome the significant negative effects associated with thermal based techniques, particularly collateral damage to surrounding structures. With further fine-tuning of parameters and longer and larger clinical trials, EPo may lead the way of adapting a safer and efficient ablation modality for the treatment of persistent AF.

Combination of ablation and left atrial appendage closure as "One-stop" procedure in the treatment of atrial fibrillation: Current status and future perspective.

Atrial fibrillation (AF), the most common arrhythmia, is a major cause of stroke and systemic embolism. Left atrial appendage closure (LAAC) has been proved to be noninferior to traditional Vitamin K antagonists (VKAs) as well as novel oral anticoagulants (NOACs), which is becoming an important alternative to prevent stroke in non‐valvular AF. Catheter‐based AF ablation (CA) is recommended to be a standard of care in patients with AF refractory to drug therapy due to a better rhythm control and improvement of life quality than antiarrhythmic drugs. Theoretically, the one‐stop combination with LAAC and CA tends to bring more benefits in patients with AF, as it not only relieves symptoms, but also reduces the risk of stroke significantly. However, several important questions still need to be considered in the combination procedure although quite a few attempts have already been made in clinical practice. This review provides a comprehensive update on the concept, technique, perioperative management, benefits and other critical issues of the “one‐stop” procedure.

Incidence and Predictors of 30-day Acute Cerebrovascular Accidents Post Atrial Fibrillation Catheter Ablation (From the Nationwide Readmissions Database)

Catheter-based ablation is increasingly being used as first-line therapy for atrial fibrillation (AF). Cerebrovascular accidents (CVA) are a known complication. In this study, we investigate the 30-day incidence and predictors of acute CVA postcatheter ablation for AF. The Nationwide Readmissions Database from 2010 to September 2015 was queried for hospitalizations with an ablation procedure and a concurrent AF diagnosis. The primary end point was a composite end point of CVA during index admission or readmission for CVA within 30 days of admission for index hospitalization. The associations between the incidence of end points and the covariates of interest; which included age, gender, hospital characteristics (size, procedural volume, urban/rural status, and teaching status), CHA2DS2-VASc co-morbidity score and its components was assessed using logistic regression. Appropriate survey weighting methodology was applied to generate nationally representative estimates. Of 67,090 weighted hospitalizations for AF ablation, 566 (0.8%) had CVA within 30 days post-ablation. In multivariate regression analysis, factors associated with CVA included hypertension (odds ratio [OR] 1.39, 95% confidence interval [CI] 1.04, 1.85), heart failure (OR 4.97, 95% CI 3.32, 7.44), previous stroke/ transient ischemic attack (OR 3.25, 95% CI 2.39, 4.42) and a lower procedural volume (OR for higher procedural volume: 0.6, 95% CI 0.42, 0.85). CHA2DS2-VASc score (OR 1.27, 95% CI 1.17, 1.39) was associated with CVA in univariate analysis. In conclusion, the CVA incidence within 30-day of catheter-based AF ablation therapy was 0.8%. Higher CHA2DS2-VASc score was associated with higher risk of CVA post-ablation. Hypertension, heart failure, previous stroke/transient ischemic attack, and procedural volume were independently associated with CVA post-ablation.

Aggregating multiple real-world data sources using a patient-centered health-data-sharing platform

Real-world data sources, including electronic health records (EHRs) and personal digital device data, are increasingly available, but are often siloed and cannot be easily integrated for clinical, research, or regulatory purposes. We conducted a prospective cohort study of 60 patients undergoing bariatric surgery or catheter-based atrial fibrillation ablation at two U.S. tertiary care hospitals, testing the feasibility of using a patient-centered health-data-sharing platform to obtain and aggregate health data from multiple sources. We successfully obtained EHR data for all patients at both hospitals, as well as from ten additional health systems, which were successfully aggregated with pharmacy data obtained for patients using CVS or Walgreens pharmacies; personal digital device data from activity monitors, digital weight scales, and single-lead ECGs, and patient-reported outcome measure data obtained through surveys to assess post-procedure recovery and disease-specific symptoms. A patient-centered health-data-sharing platform successfully aggregated data from multiple sources.

Safety and Efficacy of Uninterrupted Apixaban Therapy Versus Warfarin During Atrial Fibrillation Ablation

Thromboembolic cerebrovascular accident remains a rare but potentially devastating complication of catheter-based atrial fibrillation (AF) ablation. Uninterrupted oral anticoagulant therapy with warfarin has become the standard of care when performing catheter-based AF ablation. Compared with warfarin, apixaban, a factor Xa inhibitor, has been shown to reduce the risk of stroke and major bleeding in nonvalvular AF. With an increase in apixaban use for stroke prophylaxis in patients with AF, there is an increased interest in the safety and efficacy of uninterrupted apixaban therapy during AF ablation. We compared the safety and efficacy of uninterrupted OA therapy with either warfarin or apixaban in all patients who underwent catheter-based AF ablation at the University of Alabama at Birmingham and at Augusta University Medical Center from January 7, 2013, to February 25, 2016. All patients underwent a transesophageal echocardiogram on the day of their ablation to assess for the presence of intracardiac thrombi. All complications were identified and classified as bleeding, thromboembolic events, or other. A total of 627 patients were analyzed as described earlier. There were 310 patients in the warfarin group and 317 patients in the apixaban group. There were 8 complications in the warfarin group and 5 complications in the apixaban group (p= 0.38). There were no thromboembolic complications in either group. In conclusion, the use of apixaban is as safe and effective as warfarin for uninterrupted OA therapy during catheter-based ablation of AF.

Real-world outcomes, complications, and cost of catheter-based ablation for atrial fibrillation: an update.

Catheter-based ablation for atrial fibrillation is a useful and effective form of rhythm-control therapy for symptomatic patients. This article reviews the 'real-world' experience on the outcomes, complications, and costs of atrial fibrillation ablation. Currently, real-world outcomes of atrial fibrillation ablation are derived from retrospective analysis of administrative databases or prospective registries from selected centers and patients. The rate of atrial fibrillation recurrence was reported to be as high as 60% and the rate of repeat ablation ranged from ≈10 to 18% within 1 year after ablation. All-cause hospitalizations after atrial fibrillation ablation were frequent, at up to ≈30% within 1 year and with up to half of them related to atrial fibrillation recurrence or repeat procedures. Rates of periprocedural complications were relatively low (≈3%). Female sex was associated with higher risk of complications such as bleeding, vascular injury, and tamponade. Markov models examining the cost-effectiveness of ablation yielded favorable results when success rates of more than 70% were assumed with long time horizons (>5 years). The real-world outcomes of atrial fibrillation ablation are sobering. Confirmation of these findings with prospective, population-based, minimally biased studies is needed. There is a critical need to delineate the downstream economic impact of atrial fibrillation ablation on society to justify its continued delivery and growth.

Esophageal Temperature Monitoring During Radiofrequency Ablation of Atrial Fibrillation: A Meta-Analysis.

Objective: Atrio-esophageal fistula is an infrequent but devastating complication of catheter-based ablation of atrial fibrillation (AF). Thermal esophageal injury may be the precursor of atrio-esophageal fistula. Here, we evaluated the role of esophageal temperature monitoring in preventing thermal esophageal injury during pulmonary vein isolation for AF with radiofrequency energy. Methods: In this meta-analysis, we searched the PubMed, Cochrane, Scopus, Embase, and Refworks databases for all published studies from January 2004 to June 2016 to evaluate the role of esophageal temperature monitoring. We searched for terms esophageal temperature monitoring, AF, radiofrequency ablation, atrio-esophageal fistula, and thermal esophageal injury. We included studies comparing luminal esophageal temperature (LET) monitoring with no LET monitoring during radiofrequency ablation of AF. We excluded studies in which post-ablation esophagogastroduodenoscopy (EGD) was not performed to identify esophageal thermal injuries. To perform the meta-analysis, we used Review Manager statistical software and a fixed-effects modeling to derive the outcomes. Given significant heterogeneity between the studies, we used meta-regression analysis to adjust for age and sex. Results: We identified 4 non-randomized controlled trials that met our search criteria and included a total of 411 patients (n=235 in the LET monitoring group; n=176 in the no LET monitoring group) in the analysis. There were 21 (8.9%) patients with thermal esophageal injury in the LET monitoring group and 12 (6.8%) in the no LET monitoring group. The pooled odds ratio was 0.66 (0.23-1.89), indicating no statistically significant differences between the 2 groups with regard to esophageal injury. Because of the small sample size and the non-randomized nature of the trials, we observed significant heterogeneity in outcomes among the trials. Conclusion: The role of esophageal temperature monitoring in reducing the risk of esophageal thermal lesions during pulmonary vein isolation for AF has not been established, and more studies including randomized controlled trials are needed to assess its true impact.

What is Established and What is New in Ablation of Persistent Atrial Fibrillation?

Catheter-based ablation of atrial fibrillation (AF) is an established treatment option for symptomatic patients who are refractory to drug-based treatment, as implemented in the latest guidelines for the management of AF.1 The accepted and recommended cornerstone of all ablation strategies for AF is electrical isolation of the pulmonary veins (PV).2 However, in addition to PV isolation (PVI), ablation strategies for persistent or even long-standing persistent AF are heterogeneous.

A decade of complex fractionated electrograms catheter-based ablation for atrial fibrillation: Literature analysis, meta-analysis and systematic review

BackgroundIt has been a decade since the complex fractionated atrial electrograms (CFAEs) were first established following the publication of Nademanee's standards. However, the status and focus of CFAE research are unclear, as is the efficacy of additional CFAE ablation in atrial fibrillation (AF). This literature review and meta-analysis were designed to determine the status of CFAE research and the efficacy and complications of CFAE ablation alone, pulmonary vein isolation (PVI) alone and PVI plus CFAE ablation in AF. MethodsWith the assistance from reference librarians and investigators trained in systematic review, we conducted a literature search of MEDLINE (via PubMed), Embase, the Cochrane Library, ScienceDirect, Wiley Blackwell and Web of Knowledge, using “complex fractionated atrial electrograms” for MeSH and keyword search. ResultsThe literature on CFAEs increased from 2007, mainly focusing on mapping studies, with mechanism studies increasing significantly from 2012. Fifteen trials with 1525 patients were qualified for our meta-analysis. Success rates were as follows. Overall (P < 0.001): CFAE ablation alone, 23.5–26.2%; PVI, 64.7%; PVI plus CFAE ablation, 67.0%. Single ablation: PVI, 60.4%; PVI plus CFAEs, 68.8% (OR 1.53, 95% CI 1.07–2.20, P = 0.02). Re-ablation: PVI, 69.0%; PVI plus CFAEs, 77.2% (OR 1.54, 95% CI 1.06–2.24, P = 0.02). Paroxysmal AF: PVI, 76.7%; PVI plus CFAEs, 79.1% (OR 1.20, 95% CI 0.79–1.81, P = 0.39). Persistent or permanent AF: PVI, 47.9%; PVI plus CFAEs, 58.7% (OR = 1.59, 95% CI 1.13–2.24, P = 0.008). Complication rates: PVI, 2.6%; PVI plus CFAEs, 3.4% (OR 1.22, 95% CI 0.58–2.57, P = 0.61). ConclusionsIn the literature, CFAE mapping studies preceded mechanism studies. CFAE ablation alone is insufficient for the treatment of AF. Additional CFAE ablation after adequate PVI or PVI plus linear ablation improves the outcome of single ablation and re-ablation without increasing complications, especially in persistent or permanent AF. There are insufficient data to support a similar improvement in paroxysmal AF or inducible AF after PVI for paroxysmal AF.

Systematic review and meta-analysis of chronic kidney disease as predictor of atrial fibrillation recurrence following catheter ablation

Recent observational studies have shown that patients with chronic kidney disease (CKD) have higher risk of atrial fibrillation (AF) recurrence and, therefore, the value of catheter ablation therapy in patients with CKD has been doubted. The purpose of this meta-analysis was to systematically analyze the effect of CKD on recurrence of AF following catheter ablation. PubMed and Cochrane clinical trials databases were searched until August 2012. Of the 1966 initially identified studies, 4 observational studies with 1379 patients were analyzed. The meta-analysis of these studies showed that CKD was associated with higher AF recurrence rate following single catheter ablation (HR = 1.96, 95% CI 1.35-2.85, p = 0.0004) while there were significant differences between individual trials (p = 0.07 and I2 = 58%). Sensitivity analysis suggested that this outcome was stable. A subgroup analysis showed that CKD has higher recurrent risk in patients with 100% paroxysmal AF (HR = 2.45, 95% CI 1.28-4.70, p = 0.007) than in patients with non 100% paroxysmal AF (HR = 1.65, 95% CI 1.15-2.36, p = 0.006). CKD was associated with higher AF recurrence rate following single catheter ablation. In addition, patients with 100% paroxysmal AF have higher risk than patients with non 100% paroxysmal AF that merits special consideration when evaluating patients for catheter-based AF ablation. Given that the CKD prevalence is rapidly increasing, there is an imperative need for better risk stratification of catheter ablation candidates.

Minimally Invasive Stand-Alone Cox-Maze Procedure for Patients With Nonparoxysmal Atrial Fibrillation

Catheter-based ablation for atrial fibrillation (AF) performed percutaneously is shown to be limited in patients with nonparoxysmal AF (non-PAF). The full Cox-Maze surgical procedure demonstrated good success with non-PAF, but concerns were raised regarding increased morbidity eliminating the effect of the success rate. This study assessed the safety and efficacy of a stand-alone on-pump Cox-Maze procedure for non-PAF. Since 2005, 104 stand-alone Cox-Maze procedures for non-PAF were performed through a right minithoracotomy (6 cm) with femoral cannulation. Patients were monitored prospectively through our AF registry. Rhythm was verified by electrocardiogram and 24-hour Holter monitoring. Health-related quality of life (SF-12 Health Survey, Quality Metric, Lincoln, RI) and AF symptoms were assessed. Patients were a mean age of 55.9±9.0 years, and 78% had long-standing persistent AF. Patient outcomes included no operative (30 days) deaths or renal failure, 1 pacemaker, and 1 transient ischemic attack. The return to sinus rhythm at 6, 12, 24, 36 months was 94%, 94%, 92%, 92%, and off antiarrhythmic drugs was 87%, 87%, 79%, 80%, respectively. The success rate at 6 months after the initial 20 patients improved from 89% to 94%. Multivariate analysis found duration of AF predicted rhythm at 6 months (odds ratio, 1.15; 95% confidence interval, 1.01 to 1.31; p=0.04). Significant improvement was noted for health-related quality of life and decreased AF symptoms at 1 year. The long-term success rate after the Cox-Maze III procedure in a challenging group of non-PAF patients is acceptable. Our experience suggests the development of educational strategies to overcome the initial learning curve and patient selection criteria for AF surgical ablation.

Ten-year trends in the use of catheter ablation for treatment of atrial fibrillation vs. the use of coronary intervention for the treatment of ischaemic heart disease in Australia

Percutaneous coronary intervention (PCI) and catheter ablation are well-accepted therapeutic interventions for treatment of coronary artery disease and atrial fibrillation (AF), respectively. We sought to examine temporal trends in the provision of these services over the past decade in Australia. A retrospective review of the numbers of PCIs and AF ablations from 2000/01 to 2009/10 was performed on data from three sources: the Australian Institute of Health, Welfare and Aging (AIHW), Medicare Australia database (MA), and local records at a high volume tertiary referral centre (RMH) for AF ablation. Linear regression models were fitted comparing trends in population-adjusted procedural numbers over the 10-year period. There was a 5% per year population-adjusted increment in PCIs over 10 years from both the AIHW and MA sources, respectively (P < 0.001). This was similar to the growth rate of all cardiovascular procedures (AIHW: 5.1 vs. 3.8%/year, P = 0.27). Atrial fibrillation ablations showed a 30.9, 23.2, and 39.8% per year population-adjusted increment over 10 years from the AIHW, MA, and RMH sources respectively (P < 0.001 for all). Growth of AF ablations was significantly higher than PCIs (P < 0.001 for AIHW and MA sources) and all cardiovascular procedures (AIHW: 30.9 vs. 3.8%/year, P < 0.001). The provision of catheter-based AF ablation services in Australia has increased exponentially over the past decade. Its annual growth rate exceeded that of PCIs and all cardiovascular procedures. Given the increasing epidemic of AF, these data have critical implications for public health policy assessing the adequacy of infrastructure, training, and funding for AF ablation services.

Emergency Valve Re-Replacement for Embolization of Prosthetic Mitral Valve Disc During Catheterization Procedure

A 47-year-old woman with a mechanical mitral valve underwent a catheter-based atrial fibrillation ablation procedure, which was complicated by the dislodgment and immediate embolization of one of the valve leaflets. Acute severe mitral regurgitation and cardiogenic shock developed, necessitating emergency reoperative mitral valve re-replacement. She subsequently underwent a successful staged retrieval of the embolized leaflet from the abdominal aorta.

Common atrial fibrillation risk alleles at 4q25 predict recurrence after catheter-based atrial fibrillation ablation

Common single nucleotide polymorphisms at chromosome 4q25 (rs2200733, rs10033464) are associated with both lone and typical atrial fibrillation (AF). Risk alleles at 4q25 have recently been shown to predict recurrence of AF after ablation in a population of predominately lone AF, but lone AF represents only 5%-30% of AF cases. To test the hypothesis that 4q25 AF risk alleles can predict response to AF ablation in the majority of AF cases. Patients enrolled in the Vanderbilt AF Registry underwent 378 catheter-based AF ablations (median age 60 years; 71% men; 89% typical AF) between 2004 and 2011. The primary end point was time to recurrence of any nonsinus atrial tachyarrhythmia (atrial tachycardia, atrial flutter, or AF). Two-hundred atrial tachycardia, atrial flutter, or AF recurrences (53%) were observed. In multivariable analysis, the rs2200733 risk allele predicted a 24% shorter recurrence-free time (survival time ratio 0.76; 95% confidence interval [CI] 0.6-0.95; P = .016) compared with wild type. The heterozygous haplotype demonstrated a 21% shorter recurrence-free time (survival time ratio 0.79; 95% CI 0.62-0.99) and the homozygous risk allele carriers a 39% shorter recurrence-free time (survival time ratio 0.61; 95% CI 0.37-1.0; P = .037). Risk alleles at the 4q25 loci predict impaired clinical response to AF ablation in a population of patients with predominately typical AF. Our findings suggest that the rs2200733 polymorphism may hold promise as an objectively measured patient characteristic that can be used as a clinical tool for selecting patients for AF ablation.

Relation of Morbid Obesity and Female Gender to Risk of Procedural Complications in Patients Undergoing Atrial Fibrillation Ablation

Obese patients with atrial fibrillation (AF) are frequently treated with AF ablation. We sought to examine whether a body mass index (BMI) threshold exists beyond which the odds of experiencing a complication from AF ablation increases. All patients enrolled in the Vanderbilt AF Registry who underwent catheter-based AF ablation from May 1999 to February 2012 were included. Major complications were recorded. Morbid obesity was defined as a BMI >40 kg/m(2) and examined in multivariable analysis. A total of 35 complications (6.8%) occurred in 512 ablations. Morbidly obese patients experienced a greater rate of complications (6 of 42, 14.3%) than the nonmorbidly obese (29 of 470, 6.2%; p = 0.046). Using a discrete BMI cutoff, the odds of complications increased 3.1-fold in those with morbid obesity (odds ratio [OR] 3.1, 95% confidence interval [CI] 1.1 to 8.4, p = 0.03) and 2.1-fold for female gender (OR 2.1, 95% CI 1.04 to 4.38, p = 0.04). With BMI as a continuous variable, the odds of complications increased by 5% per 1 unit increase in BMI (OR 1.05, 95% CI 1.0 to 1.11, p = 0.05), and the increase for female gender was 2.2-fold (OR 2.2, 95% CI 1.1 to 4.6, p = 0.03). In conclusion, morbid obesity represents a BMI threshold above which the odds of complications with AF ablation increase significantly. The increase in complications appears to be driven primarily by events in women, suggesting that morbidly obese women are a special population when considering AF ablation.