Richard G. Bennett

Background and Aims: Frequent premature ventricular complexes (PVCs) are often observed in patients undergoing ablation of atrial fibrillation (AF). However, the relationship between AF ablation and PVCs is uncertain. The purpose of this study was to examine the prevalence of frequent PVCs before and after catheter ablation of AF. Methods: This was a retrospective cohort study of patients undergoing ablation of AF at two tertiary centers. All patients undergoing initial or repeat ablation of AF were eligible. Patients were followed in AF clinics before and after ablation with routine ambulatory ECG monitoring. Results: The cohort consisted of 421 patients (mean 63 years, 33% female, 57% paroxysmal). At baseline, 18.4% and 4.7% had ≥ 1% and ≥ 5% PVCs respectively. In the 179 days post‐ablation, 9.0% developed new onset ≥ 1% PVCs, whereas 10.9% of patients had regression from ≥ 1% to < 1% PVCs. In the total follow up period of 2 years, there was a significant increase in the proportion of patients with ≥ 1% PVCs. Multivariable modeling revealed baseline PVC burden and hypertension as the only predictors of an increasing PVC burden in the post‐ablation period. Conclusion: Frequent PVCs are highly prevalent among patients undergoing AF ablation. However, there was no signal of an increase in frequent PVCs in the immediate post‐ablation period.

Background: Wearable ECG-enabled smartwatches have been validated for atrial fibrillation (AF) screening, but their accuracy for monitoring AF recurrence and quantifying AF burden after catheter ablation is uncertain. Objectives: To evaluate the simulated performance of three commercial smartwatch algorithms for AF recurrence detection and AF burden estimation compared with implantable cardiac monitors (ICMs). Methods: Using continuous ICM data from 346 patients in the CIRCA-DOSE trial, we simulated three smartwatch algorithms, assuming daytime wear (8:00 AM–10:00 PM). We also simulated commonly-used non-invasive intermittent rhythm monitoring strategies. Primary endpoints were sensitivity for arrhythmia recurrence and correlation with ICM-derived AF burden. Analyses were stratified by daily wear time and patient activity. Results: AF recurrence occurred in 47.1% of patients. Simulated detection sensitivities were 82.2% (Apple Watch AF Burden), 70.6% (Apple Watch IRN), and 64.4% (Fitbit IHRD), compared with 15.8%–64.6% for simulated intermittent AECG monitors. Wearables outperformed commonly-used Holter/patch monitoring strategies. AF burden correlation with ICM exceeded r = 0.97 for all algorithms. Among missed recurrences, median AF burden was 90% with 24-hour use), whereas patient activity modestly reduced detection. Conclusions: Smartwatch-based AF detection algorithms demonstrate strong correlation with ICM-derived AF burden and clinically good sensitivity for recurrence detection, outperforming conventional non-invasive strategies. These findings support the integration of wearables as a scalable alternative for post-ablation rhythm monitoring.

BACKGROUND: Multiple extrastimulus (ES) pacing protocols exist for ventricular substrate mapping. Despite being increasingly adopted in clinical practice, direct protocol comparisons have been limited. This study aims to compare the substrate delineation and mapping efficiency of right ventricular pacing+ES (RVp+ES) and sensed ES pacing strategies in a large animal ischemia-reperfusion injury model. METHODS: Four swine underwent 90-minute balloon occlusion of the mid-left anterior descending artery, followed by late gadolinium-enhanced cardiac magnetic resonance between days 30 and 58 and invasive electroanatomic mapping. Late gadolinium-enhanced cardiac magnetic resonances were segmented for scar topography and border zone channel geometry. RESULTS: Sensed ES substrate maps had greater point density (12.90±4.20 pts/cm ² versus 5.75±0.52 pts/cm ² ; P =0.032) and faster acquisition (113.71±22.38 s/pt per cm ² versus 228.57±77.30 s/pt per cm ² ; P =0.027) than RVp+ES. Despite this, RVp+ES substrate maps had greater uncovering of split potentials within border zone channels (76.5% [15.4%–95.5%] versus 16.7% [0%–52.9%]; P =0.028), higher sensitivity (53% versus 30%), and similarly high specificity (91% versus 93%) than sensed ES, as well as better visual correlation on decrement-evoked potential maps. Bipolar voltage in sinus rhythm and RVp did not reliably predict tissue response to ES, with 46% to 57% of split potentials within border zone channels arising from seemingly normal voltage (≥1.5 mV). CONCLUSIONS: RVp+ES is more sensitive than sensed ES and highly specific for the detection of late gadolinium-enhanced cardiac magnetic resonance border zone channels postmyocardial infarct.

BACKGROUND: Atrial tachyarrhythmia recurrence remains the primary end point of clinical trials evaluating therapeutic pharmacological and nonpharmacological interventions for atrial fibrillation (AF). We sought to examine the relationship between the timing of first atrial tachyarrhythmia recurrence and subsequent AF burden. METHODS: We performed a patient-level analysis of 2 multicenter prospective parallel-group, single-blinded randomized clinical trials that used continuous rhythm monitoring after rhythm intervention. Patients with paroxysmal AF were stratified based on the month where the first recurrence of atrial tachyarrhythmia was observed, after a 2-month blanking period. AF burden was calculated as the time spent in AF at 1 year after first recurrence and over 3 years of follow-up. RESULTS: A total of 51.7% of patients experienced a recurrence of atrial tachyarrhythmia in the first year of follow-up. A first recurrence of atrial tachyarrhythmia occurred in 56.5% of patients within the third month post treatment initiation, with 79.5% of all recurrences detected by month 6 and 90.2% detected by month 9. The median postrecurrence AF burden was significantly greater in those with first recurrence in month 3 (1.04% [interquartile range, 0.23–5.05]) when compared with those patients with first recurrence between months 4 to 12 (0.13% [interquartile range, 0.04–0.63]; P P <0.0001 versus month 3). CONCLUSIONS: Atrial tachyarrhythmia recurrence after rhythm control intervention for paroxysmal AF is not uniform, with earlier recurrences being associated with higher AF burden on follow-up. These findings suggest that the timing of arrhythmia recurrence is of critical importance, with later recurrences being of progressively lesser clinical significance.