Impact of a time-to-effect-guided ablation protocol in cryoballoon ablation on the durability of pulmonary vein isolation.

BACKGROUND: Cryoballoon (CB)-based pulmonary vein isolation (PVI) has proven to be as effective as radiofrequency-based ablation. Different ablation protocols took the individual time-to-isolation (TTI) into account aiming at shorter but equally or even more effective freeze cycles. The current study sought to assess the impact of the TTI on PVI durability in patients undergoing a repeat procedure for recurrence of atrial tachyarrhythmia (ATA). METHODS AND RESULTS: In 205 patients with ATA recurrence after previous CB-based PVI, a total of 806 pulmonary veins (PVs) were identified. A total of 126 out of 806 PVs (16%) were previously treated with a TTI-guided ablation (Protocol #1; TTI + 120 s), in 92/806 (11%) PVs TTI was only monitored (m) but fixed freeze cycles were applied (Protocol #2; mTTI) and in 588/806 (73%) a fixed freeze cycle was applied without mTTI. There was no difference in the PV-reconduction rate between the groups (p = .23). The right inferior pulmonary vein (RIPV) showed overall significantly higher reconduction rates compared to the other PVs (RIPV-left inferior PV p < .003, -left superior PV p < .001, -right superior PV p < .013). Twenty-one patients (10%) were demonstrated to have only electrical reconduction of the RIPV, while all other PVs were still electrically isolated. CONCLUSIONS: The TTI-based CB ablation protocol did not show significant differences regarding PV-reconduction rates compared to the other ablation protocols.

Effectiveness and Safety of Cryoablation in Patients With Atrial Fibrillation Episodes of <24 h Duration: A Propensity-Matched Analysis.

Background: Paroxysmal atrial fibrillation (AF) is closely related to pathophysiologic processes and clinical outcomes. However, it is uncertain whether cryoablation of pulmonary veins isolation is effective and safe for patients with symptomatic and drug refractory AF episodes of <24-h duration. Methods: The patients were designed into Group A (253 patients with paroxysmal AF episodes of <24-h duration) and Group B (253 patients with paroxysmal AF lasting for 24 h or longer) on a 1:1 basis by identical propensity scores. Mortality, stroke/transient ischemic attack (TIA), and complications relevant to the cryoablation procedure were compared, and recurrence of atrial tachyarrhythmia was analyzed for clinical independent predictors. Results: The rate of atrial tachyarrhythmia recurrence was 21.74% in Group A and 30.04% in Group B, respectively (P = 0.042). At 12-month follow-up from the procedure, lower incidences of stroke/TIA endpoint of the patients were observed in Group A compared with Group B by Kaplan-Meier analysis [HR 0.34 (0.13-0.87), P = 0.025]. No significant differences in mortality and complications relevant to the cryoablation procedure were observed between Group A and Group B. Moreover, adjusted multivariable Cox regression analysis showed that <24-h paroxysmal AF type (HR 0.644, 95% CI: 0.455-0.913, P = 0.014) and left atrium diameter (LAD) (>40 mm) (HR 1.696, 95% CI: 1.046-2.750, P = 0.032) were independently associated with the incidence of recurrence of atrial tachyarrhythmia in the study. Conclusion: Our findings indicated that <24-h paroxysmal AF type was obviously associated with an increased success rate of cryoablation and reduced incidence of stroke/TIA during the follow-up period. Therefore, there is superior effectiveness and similar safety in patients with AF episodes of <24-h duration compared with patients with longer paroxysmal AF duration.

Defining Blanking Period Post-Pulmonary Vein Antrum Isolation.

OBJECTIVES: This study sought to determine the exact period after pulmonary vein antrum isolation (PVI) during which early recurrence of atrial tachyarrhythmia (ERAT) does not predict late arrhythmia recurrence (LR), in order to better define the blanking period. BACKGROUND: Recurrence of atrial fibrillation after PVI is not uncommon. The first 3 months after PVI have been commonly treated as a blanking period, during which ERAT is not thought to predict LR after PVI; however, recent studies have shown that ERAT does predict LR. METHODS: Baseline and follow-up data for 636 patients (mean age: 61.4 ± 10.6 years; 67.1% male; 59% paroxysmal atrial fibrillation; 31.4% ERAT) who underwent PVI between 2010 and 2014 were included. Recurrences were monitored by electrocardiography and Holter monitoring at 1-, 3-, 6-, 9-, and 12-month intervals post-procedure. Receiver-operating characteristic curve analysis was used to define the blanking period after PVI. RESULTS: Overall, 51%, 76%, and 92% of patients who had ERAT in the first, second, and third month post-PVI, respectively, also experienced LR (p = 0.001). Using a logistic regression model, those manifesting ERAT during the first, second, and third month post-PVI were 4.22, 9.03, and 19.43 (p = 0.001) times more likely to experience LR, respectively, compared to those without ERAT. Furthermore, receiver-operating characteristic analysis revealed that 23 days post-PVI is the optimal cutoff date for the blanking period, with area under the curve of 0.7, sensitivity of 69.2%, and specificity of 61.2%. CONCLUSIONS: The likelihood of experiencing LR progressively rises with ERAT after the first month post-PVI. Blanking period after PVI should be limited to the first 23 days clinically and in future studies.