Introduction: Radiofrequency ablation (RFA) slow pathway modification for catheter ablation of AV nodal reentrant tachycardia (AVNRT) is traditionally performed using a 4mm, non-irrigated (NI) RF ablation catheter. Slow pathway modification using irrigated, contact-force sensing (ICFS) RFA catheters has been described in case reports, but outcomes have not been systematically evaluated. Methods: Acute procedural outcomes of 200 consecutive patients undergoing slow pathway modification for AVNRT were analyzed. An ICFS 3.5mm RFA catheter (ThermoCool SmartTouch STSF, Biosense Webster, Inc.) was utilized in 134 patients, and a 4mm NI RFA catheter (EZ Steer, Biosense Webster, Inc.) was utilized in 66 patients. Electroanatomic maps were retrospectively analyzed in a blinded fashion to determine proximity of ablation lesions to the His region. Results: Baseline characteristics of patients in both groups were similar. Total RF time was significantly lower in the ICFS group compared to the NI group (5.53±4.6 vs. 6.24±4.9 min, p=0.03). Median procedure time was similar in both groups, ICFS 108.0 (87.5-131.5) vs. NI 100.0 (85.0-125.0) min, p=0.2). Ablation was required in closer proximity to the His region in the NI group compared to the ICFS group (14.4 ± 5.9 mm vs, 16.7 ± 6.4 mm, respectively, p=0.01). AVNRT was rendered non-inducible in all patients, and there was no arrhythmia recurrence during follow-up in both groups. Catheter ablation was complicated by AV block in one patient in the NI group. Conclusion: Slow pathway modification for catheter ablation of AVNRT using an irrigated, contact-force sensing RFA catheter is feasible, safe, and may facilitate shorter duration ablation while avoiding ablation in close proximity to the His region.

Background: Catheter ablation procedures for atrial fibrillation (AF) were significantly curtailed during the peak of coronavirus disease 2019 (COVID-19) pandemic to conserve healthcare resources and limit exposure. There is little data regarding peri-procedural outcomes of medical procedures during the COVID-19 pandemic. We enacted protocols to safely reboot AF ablation while limiting healthcare resource utilization. Objective: To evaluate acute and subacute outcomes of protocols instituted for reboot of AF ablation during the COVID-19 pandemic. Methods: Perioperative healthcare utilization and acute procedural outcomes were analyzed for consecutive patients undergoing AF ablation under COVID-19 protocols (2020 cohort; n=111) and compared to those of patients who underwent AF ablation during the same time period in 2019 (2019 cohort; n=200). Newly implemented practices included pre-operative COVID-19 testing, selective transesophageal echocardiography (TEE), utilization of venous closure, and same-day discharge when clinically appropriate. Results: Pre-ablation COVID-19 testing was positive in 1 of 111 patients. There were 0 cases ablation-related COVID-19 transmission, and 0 major complications in either cohort. Pre-procedure TEE was performed in significantly fewer 2020 cohort patients compared to the 2019 cohort patients (68.4% vs. 97.5%, p <0.001, respectively) despite greater prevalence of persistent arrhythmia in the 2020 cohort. Same day discharge was achieved in 68% of patients in the 2020 cohort, compared to 0% of patients in the 2019 cohort. Conclusions: Our findings demonstrate safe resumption of complex electrophysiology procedures during the COVID-19 pandemic, reducing healthcare utilization and maintaining quality of care. Protocols instituted may be generalizable to other types of procedures and settings.

Introduction: Left atrial posterior wall (LAPW) isolation is associated with favorable outcomes for catheter ablation of persistent atrial fibrillation (PEAF). Techniques for LAPW isolation include ablation at the periphery with or without high density ablation within the LAPW. The proportion of LA isolated by the lesion set also varies greatly. The optimal technique to achieve LAPW isolation is not clear. Objective: To assess impact of ablation lesion density within and dimensions of the LAPW isolation region on arrhythmia recurrence in catheter ablation of PEAF. Methods: LAPW lesion density and surface area relative to total LA surface area were calculated using electroanatomic maps of 110 consecutive patients undergoing LAPW isolation for PEAF (CARTO 3, Biosense Webster, Inc.). LAPW isolation was performed at the discretion of 5 experienced operators after voltage mapping. LAPW PV entrance and exit block were confirmed. Arrhythmia recurrence at two years was assessed by Kaplan-Meier analysis. Results: LAPW lesion density ranged from 0% - 99%. The proportion of LA surface area isolated ranged from 35% - 75%. There was no significant difference in arrhythmia-free survival stratified by median LAPW ablation density (31% vs. 27%, p=0.8) or median proportion of electrically-isolated LA surface area (31% vs. 27%, p=0.8%). Voltage map-guided LAPW isolation did not significantly decrease arrhythmia recurrence (29% vs. 28%, p=1). Conclusion: Neither the density of ablation within nor the dimensions of the LAPW isolated region predicted arrhythmia-free survival for catheter ablation of PEAF. Voltage map-guided LAPW isolation resulted in similar ablation efficacy regardless of LA scar burden.