Comparison of Direct Current Synchronized Cardioversion to Ibutilide-Guided Catheter Ablation for Long-Term Sinus Rhythm Maintenance After Isolated Pulmonary Vein Isolation of Persistent Atrial Fibrillation

Failure of intravenous nifekalant cardioversion as an independent predictor for persistent atrial fibrillation recurrence after catheter ablation

AIMS

Nifekalant is a class III antiarrhythmic drug that exerts antiarrhythmic effects by inhibiting rapid rectifying potassium channels and extending the effective refractory period of cardiomyocytes. It has a high success rate in converting atrial fibrillation (AF) to sinus rhythm. Whether the failure of intravenous nifekalant cardioversion is an independent predictor for persistent AF recurrence after catheter ablation has not been reported.

METHODS

A total of 92 patients with drug-refractory persistent AF were retrospectively enrolled. After all ablations, intravenous nifekalant was administrated. Patients were assigned to the success group (group 1) and failure group (group 2) based on nifekalant cardioversion results and followed for 12 months to note any episode of atrial arrhythmia recurrence.

RESULTS

Each group included 46 patients. After 12 months of follow-up, nine (19.6%) patients from group 1 and 23 (50.0%) patients from group 2 had a recurrence of atrial tachyarrhythmia (P = 0.002). AF duration and type 2 diabetes were strongly associated with failure of intravenous nifekalant cardioversion. Univariable Cox proportional hazard regression showed that failure of intravenous nifekalant cardioversion, AF duration, and type 2 diabetes were potential risk factors. Multivariable Cox proportional hazard regression showed that failure of nifekalant cardioversion was statistically associated with AF recurrence (adjusted RR = 2.257, 95% CI: 1.006-5.066, P = 0.048). Failure of intravenous nifekalant cardioversion could bring a positive effect on the prognostic differentiation when added into the multivariable model (0.767 ± 0.042 vs. 0.774 ± 0.045, P = 0.025).

CONCLUSION

Failure of nifekalant cardioversion is an independent predictor for persistent AF recurrence after catheter ablation.

Is ablation to atrial fibrillation termination of persistent atrial fibrillation the end point?: A systematic review and meta-analysis

BACKGROUND

The ideal ablation strategy and end point for persistent atrial fibrillation (AF) have not been well founded. Defining periprocedural AF termination as the end point of catheter ablation is still controversial. This meta-analysis aimed to analyze the differences between periprocedural AF termination and non-termination in the long-term AF recurrence rate and postoperative complications.

METHODS

Randomized controlled trials (RCTs) were identified by a systematic search of electronic databases including PubMed, EMBASE, and Cochrane library from January 2008 to August 2019. The primary outcome was freedom from AF or any atrial arrhythmia without antiarrhythmic drugs at the long-term (≥12 months) follow-up. The secondary outcome was overall postoperative complication rates. The risk ratio (RR) with 95% confidence interval (CI) was pooled for these outcomes. A forest plot, fixed-effects model or random-effect model, Q test, I statistic, and Egger funnel plot were used in the statistical analysis.

RESULTS

Fourteen RCTs were included in this meta-analysis. Overall, no significant difference was found in freedom from AF at the long-term follow-up between patients in whom AF termination was achieved and not achieved (RR = 0.93, 95% CI = 0.78-1.09, P = .36, I = 69%). Patients with AF non-termination had a lower complication occurrence rate than those with AF termination (RR = 1.74, 95% CI = 1.11-2.73, P = .02, I = 0%).

CONCLUSION

Our meta-analysis suggests that AF termination is not a reliable procedural end point during ablation of persistent AF.

Correlation of left atrial wall thickness and atrial remodeling in atrial fibrillation: Study based on low-dose-ibutilide-facilitated catheter ablation

Atrial remodeling plays a significant role during the progression of atrial fibrillation (AF). Left atrial wall thickness (LAT) is a subjective and easily acquirable indicator referring to structural remodeling. Therefore, we aimed to investigate the association between LAT and atrial remodeling substrate, and to explore the predictive role of LAT about strong maintenance substrate and poor response to catheter ablation.LAT was measured by cardiac computed tomography in 2 selected locations (roof and floor) in 100 persistent AF patients. Then the low-dose-ibutilide-facilitated catheter ablation was performed and atrial maintenance substrate was categorized as weak, mild, and strong, based on the response to circumferential pulmonary vein isolation or complex fractionated atrial electrograms ablation. During follow-up, the success rate was evaluated. LAT showed a progressive thickening tendency from weak, mild, to strong maintenance substrate (roof: 2.2 mm vs. 2.6 mm vs. 3.9 mm, P < .0001; floor: 1.7 mm vs. 2.0 mm vs. 2.5 mm, P < .0001). During follow-up, the success rate of ablation was decreased with the maintenance substrate strengthening (weak 80%, mild 64.53%, strong 31.43%, P = .009). LA roof thickness >3.10 mm might be the predictor to strong atrial maintenance substrate and poor response to ablation.LAT was associated with the remodeling extent of atrial maintenance substrate and might predict the response to catheter ablation. These findings could help the clinicians to select the appropriate ablative strategy and predict the complexity and prognosis before catheter ablation.