Background Transesophageal echocardiography (TEE) is variably performed before atrial fibrillation (AF) ablation to evaluate left atrial appendage (LAA) thrombus. We describe our experience with transitioning to the pre-ablation cardiac computed tomography (CT) approach for the assessment of LAA thrombus during the COVID-19 pandemic. Methods We studied consecutive patients undergoing AF ablation at our center. The study cohort was divided into pre- vs. post-COVID groups. The pre-COVID cohort included ablations performed during 1 year before the COVID-19 pandemic; pre-ablation TEE was used routinely to evaluate LAA thrombus in high-risk patients. Post-COVID cohort included ablations performed during the 1 year after the COVID-19 pandemic; pre-ablation CT was performed in all patients, with TEE performed only in patients with LAA thrombus by CT imaging. The demographics, clinical history, imaging, and ablation characteristics, and peri-procedural cerebrovascular events (CVE) were recorded. Results A total of 637 patients (pre-COVID n=424, post-COVID n=213) were studied. The mean age was 65.6  10.1 years in the total cohort, and the majority were men. There was a significant increase in pre-ablation CT imaging from pre to post-COVID cohort (74.8 vs. 93.9%, p=<0.01), with a significant reduction in TEEs (34.6 vs. 3.7%, p=<0.01). One patient in the post-COVID cohort developed CVE following negative pre-ablation CT. However, the incidence of peri-procedural CVE between both cohorts remained statistically unchanged (0 vs. 0.4%, p=0.33). Conclusion Implementation of pre ablation CT-only imaging strategy with selective use of TEE for LAA thrombus evaluation is not associated with increased CVE risk during the COVID- 19 pandemic.

Introduction: There are limited data describing the experience of index radiofrequency (RF) vs. cryoballoon (CB) ablation for atrial fibrillation (AF) among elderly patients in the United States. Methods: We conducted a retrospective analysis of patients > 75 years of age undergoing index AF ablation between January 2010 and March 2019 at our center. Major complications and efficacy, defined as freedom from any atrial tachyarrhythmia (ATA) lasting ≥30 seconds after one year of follow-up, were assessed in patients with index RF vs. CB ablation. Predictors of ATA recurrence at 1 year follow-up were also evaluated. Results: In our cohort of 194 patients, the mean age was 78 ± 3.1 years, 58.2% were men, and 39.4% had persistent AF. The mean left atrial (LA) diameter was 4.5 ± 0.7, while the mean CHA2DS2-VASc score was 3.5 ± 1.2. The majority (n=149, 76.8%) underwent RF ablation. The incidence of complications was similar in the two sub-groups (RF: 1.3% vs. CB: 2.2%, p=0.67). No significant difference in success rate at 1-year follow-up was found between patients receiving RF vs. CB ablation (59.7% vs. 66.7%, p=0.68). In a multivariable model adjusting for the relevant covariates only LA size [HR=1.64, CI: 1.15-2.34, p<0.01] was independently associated with ATA recurrence at 1year follow-up. Conclusion: In our cohort of elderly patients undergoing index CA for AF, RF ablation was the predominant modality with similar safety and efficacy relative to CB ablation. LA size was a significant predictor of ATA recurrence at 1year independent of index ablation modality.