Prompt versus deferred conditional cardioversion strategies after early AF recurrence following pulsed field ablation

Background The optimal timing of cardioversion for sustained atrial fibrillation (AF) recurrence after pulsed-field ablation (PFA) remains uncertain. We compared prompt and deferred conditional-cardioversion strategies in relation to subsequent AF burden. Methods This retrospective cohort study included 214 adults with continuously monitored AF lasting at least 24 h during the 8-week blanking period after first-time PFA. At eligibility, each patient was cloned to two dynamic strategies: attempting cardioversion within 48 h if AF persisted or withholding nonrescue cardioversion for 7 days. Strategy deviations were artificially censored and inverse-probability weighted. The primary per-protocol estimand was the strategy difference in cumulative AF days from postablation days 57 through 365. Results Artificial censoring occurred in 35.5% and 59.3% of prompt- and deferred-strategy clones, respectively; the corresponding effective sample sizes were 124.7 and 72.9. Standardized mean cumulative AF exposure was 17.9 days under the prompt strategy and 30.5 days under the deferred strategy (mean difference, −12.6 days; 95% CI, −21.6 to −4.6; mean ratio, 0.59; 95% CI, 0.40–0.84). The risk of first sustained recurrence after day 56 was 30.7% vs. 44.1% (weighted hazard ratio, 0.64; 95% CI, 0.45–0.91). Repeat cardioversion and AF-related hospitalization were also less frequent under the prompt strategy. Continuation of the qualifying episode accounted for approximately 39% of the primary difference; after excluding this component, AF burden from distinct subsequent episodes remained lower under the prompt strategy (mean difference, −7.7 days; 95% CI, −14.9 to −1.1). Safety events were uncommon. Conclusions A strategy of attempting prompt cardioversion when AF persisted was associated with lower subsequent AF burden than temporary deferral. Randomized validation is required before defining an optimal cardioversion window or making firm management recommendations.