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BACKGROUND: Pulsed field ablation is now widely used for atrial fibrillation (AF) ablation, but atrial tachyarrhythmia recurrence remains common and postablation risk tools are limited. We assessed whether a validated sinus‑rhythm artificial intelligence— enabled ECG AF probability score, and its early postablation change, predicts recurrence after pulsed field ablation. METHODS: We studied consecutive patients undergoing index pulsed field ablation across 3 Mayo Clinic sites (February 2024–March 2025) with ≥1 sinus‑rhythm ECG within 180 days preprocedure. Baseline artificial intelligence—enabled ECG AF score (range 0–1) was the mean across baseline ECGs. Recovery indices (RI30/60/90), defined as mean postprocedure artificial intelligence—enabled ECG score within days 1–30/60/90 minus baseline, predicted post‑blanking recurrence using corresponding 30‑, 60‑, and 90‑day blanking windows. The primary outcome was time to first documented AF/atrial flutter/atrial tachycardia episode >30 seconds, ascertained via clinic ECGs, ambulatory monitoring, and device interrogations. Cox regression adjusted for prespecified clinical and echocardiographic covariates assessed associations; Harrell C‑statistic quantified discrimination. RESULTS: Among 1052 patients (67±10 years; 33% women), median baseline score was 0.35; 320 (30%) recurred over 188 days. Higher baseline score independently predicted recurrence (hazard ratio per 0.1 increase, 1.08 [95% CI, 1.03–1.14]). Scores rose on day 0 after ablation, then declined over subsequent weeks, with persistently higher, less‑improving trajectories among patients who recurred (time×recurrence interaction P <0.001). Day 0 score was not independently associated with recurrence after adjustment. Attenuated early recovery (higher recovery index) was independently associated with recurrence, most robustly for RI-90 (hazard ratio per 0.1 increase, 1.15 [95% CI, 1.07–1.24]), and improved discrimination beyond baseline and covariates (C‑statistic, 0.63–0.67; ΔC=0.04). Findings were consistent in a historical thermal ablation cohort. CONCLUSIONS: Baseline and early postablation dynamics of a sinus‑rhythm artificial intelligence—enabled ECG AF probability score are associated with pulsed field ablation recurrence and may aid multivariable risk stratification; prospective validation is warranted.

ABSTRACT Background Atrial fibrillation (AF) has been observed in adults with anomalous pulmonary venous return (APVR), but data on catheter ablation outcomes in this population remain limited to case reports and small series. Methods We retrospectively reviewed 14 adult patients with confirmed APVR who underwent catheter ablation for AF at three tertiary academic centers in the United States between July 2003 and May 2025. Baseline, procedural, electroanatomic mapping, and outcome data were collected. Freedom from atrial arrhythmia recurrence was estimated by Kaplan-Meier analysis. Results Mean age was 56 ± 13 years and 79% were male. Heart failure was present in 64%, and hypertension and coronary artery disease in 43% each. Most had partial APVR (86%), and 57% had prior surgical correction. Radiofrequency ablation was used in all patients, combined with pulsed-field ablation in one. Acute success was achieved in all patients, although areas with residual pulmonary vein or SVC electrical activity were left untreated in 3 (21%). Non-pulmonary-vein electrical activity was more common in patients with prior surgical correction than in those without (43% vs 17%). Median follow-up was 3.4 years (IQR, 2.0-9.6). Freedom from arrhythmia recurrence was 78.6% at 1 year and 53.9% at 5 years. Two patients (14%) required reablation; complications occurred in 3 (21%) without long-term sequelae. Conclusions Catheter ablation was acutely successful in all patients in this largest reported APVR cohort, despite substantial comorbidity burden and anatomic complexity. The arrhythmogenic substrate often extended beyond the anomalous vein, particularly in surgically corrected patients, supporting individualized, substrate-guided ablation in this population. CLINICAL PERSPECTIVE What Is Known Atrial fibrillation has been reported in adults with anomalous pulmonary venous return (APVR), but data on catheter ablation outcomes in this population are limited to case reports and small series. What the Study Adds In the largest reported cohort of patients with APVR undergoing catheter ablation for atrial fibrillation, pulmonary vein isolation achieved acute success in all patients despite substantial comorbidity burden and anatomic complexity. Non-pulmonary-vein sites of electrical activity were more common among patients with prior surgical correction, and postsurgical scar and epicardial venoatrial connections were also arrhythmogenic, indicating that the arrhythmogenic substrate in APVR often extends beyond the anomalous vein itself. These findings support individualized, substrate-guided mapping in patients with APVR, particularly those with a surgical history, and suggest a role for pulsed-field ablation near critical structures such as the phrenic nerve.

Abstract Aims The clinical significance of early recurrences during the blanking period following pulmonary vein isolation (PVI) remains uncertain, particularly after pulsed field ablation (PFA). This study aimed to evaluate the prognostic impact of early recurrences at 30-, 60-, and 90-day thresholds on outcomes following PFA for atrial fibrillation (AF). Methods and results Consecutive patients who underwent PFA for AF across multiple centres within the Mayo Clinic health system were included. The primary endpoint was AF-free survival. Kaplan–Meier and multivariate Cox regression analyses were performed to compare outcomes between patients with and without early recurrences using 30-, 60-, and 90-day thresholds. A total of 1162 patients were included. The estimated AF-free survival at 1 year was 70%. Early recurrences within 30-, 60-, and 90-days post-ablation were significantly associated with late recurrences beyond 90 days (hazard ratio [HR] 5.9, 95% confidence interval [CI] 4.4–7.9, P &lt; 0.01; HR 6.6, 95% CI: 5.0–8.6, P &lt; 0.01; and HR 9.1, 95% CI: 7.0–11.7, P &lt; 0.01, respectively). These findings remained significant among patients undergoing continuous rhythm monitoring. Early recurrences within 30 days in this subgroup were significantly associated with a 1-year AF burden &gt;1% or the need for repeat AF ablation (odds ratio 25.0, 95% CI: 6.6–126.8, P &lt; 0.01). Conclusion Early recurrences following PFA are strongly predictive of long-term arrhythmia recurrence and are unlikely to represent transient inflammatory phenomena. Accordingly, the applicability of the conventional blanking interval after PFA should be reconsidered.

BACKGROUND: Cavotricuspid isthmus (CTI) ablation is frequently performed either as a standalone procedure or in combination with pulmonary vein isolation. With the rapid adoption of pulsed field ablation for atrial fibrillation, it is essential to delineate the utility of this modality in treating CTI-dependent atrial flutter (AFL). This study aims to evaluate the procedural and clinical outcomes of CTI ablation using pulsed field energy. METHODS: We conducted a retrospective analysis of consecutive patients who underwent pulsed field ablation for CTI-dependent AFL between January 2024 and March 2025. The primary end points were acute procedural success, periprocedural complications, and CTI-dependent AFL recurrence during follow-up. RESULTS: A total of 132 patients underwent CTI nonthermal ablation. The median age was 69.5 years, and 27.3% were female. The Farawave catheter was used in 93.9% of cases, PulseSelect in 4.5%, and Sphere-9 in 1.5%. Acute block was achieved in 99.2% of patients, although 8 required adjunctive radiofrequency ablation to complete the line. Periprocedural complications included transient ST-segment elevation in 2 patients and transient conduction disturbances in 3. During a median follow-up of 114 days (n=131), 5 patients (3.8%) experienced recurrence of typical AFL. The 6-month typical AFL-free survival estimate was 93.6%. CONCLUSIONS: Pulsed field ablation appears to be a feasible and effective strategy for CTI-dependent AFL. However, anatomic variability may limit its universal applicability with current catheter designs. Although acute procedural success is high, the long-term durability of the CTI block and its comparative efficacy versus conventional thermal ablation remain areas requiring further investigation.

Background: Pulsed Field Ablation (PFA) has gained widespread adoption for pulmonary vein isolation (PVI) due to its tissue selectivity and safety profile. However, its role in cavotricuspid isthmus (CTI) ablation for typical atrial flutter is less defined. This study compares CTI ablation using PFA versus radiofrequency ablation (RFA) in patients undergoing PVI exclusively with PFA. Research Question: We hypothesized that in patients undergoing PFA-based PVI, CTI ablation using PFA would reduce procedure and fluoroscopy times without increasing complication or flutter recurrence rates compared to RFA. Methods: We retrospectively analyzed patients who underwent CTI ablation with either PFA or RFA alongside PFA PVI between 2024 – 2025 across all Mayo Clinic sites. Baseline characteristics, procedural parameters, acute success, and 12-month arrhythmia recurrence were compared between groups. All patients received standard follow-up, including ECGs and Holter monitoring. Results: A total of 350 patients were included (CTI PFA: n = 126; CTI RFA: n = 224). Patients in the PFA group were older (68.8 ± 8.5 vs. 65.7 ± 10.1 years; p <0.01) and had higher CHA2DS2-VASc scores (2.84 ± 1.57 vs. 2.45 ± 1.45; p = 0.02). Fluoroscopy (18.9 ± 9.1 vs. 25.2 ± 23.3 min; p < 0.01 ) and procedure times (172.6 ± 22.4 vs. 224.7 ± 74.2 min; p < 0.01) were significantly lower in the PFA group. Complication rates (8.7% vs. 4.9%; p = 0.15) and typical flutter recurrence (3.1% vs. 1.7%; p = 0.46) were similar between groups during a mean follow-up of 125 days. Conclusion: In patients undergoing PVI with PFA, CTI ablation using PFA is associated with significantly reduced procedure and fluoroscopy times compared to RFA, without increased complications or arrhythmia recurrence. These findings support the feasibility and efficiency of PFA for typical flutter ablation when performed during PFA-based AF procedures.

Background: A blanking period allowing for atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI) has historically been standardized to 90 days. With the recent introduction of pulsed field ablation (PFA) for PVI and emerging in vitro data suggesting a shorter inflammatory timeframe, it remains unclear whether recurrences during this 90-days period reflect incomplete procedural success or merely transient inflammatory changes. Research Question: In patients undergoing PVI with PFA, do early AF recurrences at 30, 60, and 90 days predict late AF recurrences beyond the standardized 90-day blanking period? Methods: Patients undergoing PFA for AF were retrospectively included. Procedures were performed under general anesthesia, and high-density (HD) mapping, with PVI and additional ablation lines applied at the operator’s discretion. PFA catheters included Farawave, PulseSelect, and Sphere-9. AF recurrences were defined as documented episodes on 12-lead ECG or cardiac monitoring devices, confirmed by interpretation from an experienced cardiologist. Survival analyses were conducted based on the occurrence of early recurrences at 30, 60, and 90 days post-ablation. Kaplan-Meier curves and hazard ratios were reported. This study was approved by our institutional review board. Results: To the best of our knowledge, this is the largest real-world study reporting outcomes of PFA for AF in the United States. A total of 1,214 patients were included in the analysis. Mean age was 66.4 years; 31.9% were female, and 22.4% underwent redo PVI. Six-month AF recurrence-free survival was 79% (95% CI, 75–83%) for the overall cohort. Patients experiencing early recurrence at 30, 60, and 90 days had a significantly higher risk of AF recurrence beyond the standardized 90-day blanking period (HR 4.0, 95% CI 2.7–5.9, P < 0.01; HR 5.0, 95% CI 3.6–7.1, P < 0.01; and HR 6.9, 95% CI 4.9–9.6, P < 0.01, respectively). Conclusion: Early recurrences at 30, 60, and 90 days post-ablation are strongly associated with atrial fibrillation recurrence beyond the 90-day blanking period. These findings challenge the traditional concept of blanking period after PFA and suggest that early recurrence may indicate incomplete procedural success rather than transient inflammation.