Introduction: Cryoablation therapy for pulmonary vein isolation (PVI) to treat paroxysmal atrial fibrillation (PAF) is well established. A novel 28 mm cryoballoon system designed to operate under low pressure to safely reach a lower nadir temperature and maintain constant balloon size during cooling has not been prospectively studied in a large patient population for safety and efficacy. The FROZEN AF (NCT04133168) trial was an international multi-center, open-label, prospective, single-arm study on the safety and performance of a novel cryoballoon system for treatment of PAF. Methods and Results: The study enrolled patients at 44 sites in 10 countries across North America, Europe, and Asia. Subjects were indicated for PVI treatment of PAF and had failed or were intolerant of 1 or more antiarrhythmic drugs. Procedural outcomes were defined based on the 2017 HRS consensus statement. Follow-up was performed at 7 days, 3, 6, and 12 months. Data are reported as mean±SD or Median (IQR). PVI was performed with a 28mm cryoballoon in 325 drug refractory PAF patients. Complete PVI was achieved in 95.7% of patients. In cryoablation lesions longer than 60s, 60.1% of PV isolations required only a single cryoballoon application. Procedure related complications included: phrenic nerve palsy [transient 4 (1.2%), persistent 0 (0.0%)], cardiac tamponade/perforation 2 (0.6%), and air embolism 1 (0.3%). Freedom from documented atrial arrhythmia recurrence at 12 months was 79.9% (AF 82.7%, AFL 96.5%, AT 98.1%), Antiarrhythmic drugs (AAD) were continued or re-initiated in 26.8% of patients after the 3-month blanking period. Additionally, an extension arm enrolled 50 pts for treatment with 28/31mm variable size cryoballoon. A single temporary PNP occurred in this group, which resolved prior to discharge. Freedom from documented recurrence at 12 months in these pts was 82.0%. Conclusions: This novel cryoballoon may facilitate PVI to treat PAF, providing more options to address the variety of anatomy present in patients with PAF. This cryoballoon system was safe and effective for treatment of patients with drug refractory or drug intolerant PAF.

Introduction: Pulmonary vein isolation (PVI) using radiofrequency (RF) and cryoballoon (Cryo) ablation are standard approaches for rhythm control of symptomatic atrial fibrillation. Both strategies involve scar formation of the left atrium (LA). There have been few studies investigating the differences in residual fibrosis and scar formation in patients undergoing RF and Cryo using cardiac magnetic resonance imaging (CMR).     Methods: The current study is a sub-analysis of the control arm of the Delayed-Enhancement MRI Determinant of Successful Catheter Ablation of Atrial Fibrillation study (DECAAF II). The study was a multicenter, randomized, controlled, single blinded trial that evaluated atrial arrhythmia recurrence (AAR) between PVI alone and PVI plus CMR atrial fibrosis guided ablation. Pre-ablation CMR and 3–6-month post ablation CMR were obtained to assess baseline LA fibrosis and scar formation respectively.     Results: Of the 843 patients randomized in the DECAAF II trial, we analyzed the 408 patients in the primary analysis control arm that received standard PVI. Five patients received combined RF and Cryo ablations so were excluded from this sub-analysis. Of the 403 patients analyzed, 345 underwent RF and 58 Cryo. The average procedure duration was 146 minutes for RF and 103 minutes for Cryo (p = 0.001). The rate of AAR at ~15 months occurred in 151 (43.8%) patients in the RF group and 28 (48.3%) patients in the Cryo group (p = 0.62). On 3-month post CMR the RF arm had significantly more covered fibrosis (3.6% vs. 3.0%, p = 0.04) and scar (8.8% vs. 6.4%, p = 0.001) compared to Cryo. Patients with ≥ 6.5% LA scar on 3-month post CMR had less AAR independent of ablation technique (RF p = 0.009, Cryo p = 0.02). Cryo caused a greater percentage of right and left pulmonary vein (PV) scar (p = 0.04, p = 0.02) and less non-PV scar (p = 0.009) compared to RF. On Cox regression Cryo patients free of AAR had a greater percentage of left PV scar (p = 0.01) and less non-PV scar (p = 0.004) compared to RF free of AAR.     Conclusion: In this sub-analysis of the control arm of the DECAAF II trial, there was no significant difference in the rate of AAR in patients undergoing PVI alone between RF vs. Cryo. Post ablation LA scar ≥ 6.5% predicted freedom from AAR, independent of ablation technique. Cryo formed a greater percentage of PV scar and less non-PV scar compared to RF, which may have prognostic implications.

Introduction: Larger left atrial appendage (LAA) ostium area and greater left atrial (LA) volume have been associated with an increased risk of ischemic stroke. Catheter ablation (CA) of atrial fibrillation (AF) leads to morphological and functional changes within the LA and LAA, some of which are not well studied. Here, we present findings regarding post-ablation changes of the LAA ostia and correlate them with various LA, LAA and left ventricular (LV) functional and morphological metrics. Methods: This retrospective analysis included patients scheduled to undergo first-time radiofrequency CA for AF. Catheter ablation techniques included PVI with or without additional ablations. Cardiac magnetic resonance imaging (CMR) was used to assess LA, LAA and LV morphology and function, including LAA ostium area, LA/LAA volume and volume index, LA ejection fraction, LA strain, and LV ejection fraction. A Kruskal-Wallis test was used for correlating LAA ostial dimensions with other LA morphological and functional metrics. The t-test or two-sample Wilcoxon test were used to compare LA and LAA morphological parameters. Results: A total of 101 patients with AF were included in this study. The mean age was 60.1 ± 11.1 years, 69% were male, the average BMI was 29.22 ± 5.08. The LAA ostial area reduced significantly from 3.84 ± 1.15 cm 2 before ablation to 3.42 ± 0.96 cm 2 after ablation (p=0.0004). This reduction was asymmetrical, as the minor axis length decreased from 1.92 cm to 1.77 cm without significant changes in the major axis. LVEF increased from a pre-ablation average of 48.26% to a post-ablation average of 53.62% (p=0.015). Correlation of pre-ablation LVEF and LAA ostium area showed a near-significant negative trend (r=-0.21, p=0.083). LAEF correlated negatively with LAA ostial area (r=-0.289, p=0.0057), total LA strain (r=-0.248, p=0.0185), and passive LA strain (r=-0.208, p=0.049). Conclusion: There is a significant asymmetrical reduction of the LAA ostial area after AF ablation that is independent of LVEF changes. Larger LAA ostial area was associated with lower LAEF and LA strain. Remodeling of the LAA after AF ablation may help account for reduced risk of stroke and increased cardiac function.

Background: Specific details about cardiovascular complications, especially arrhythmias, related to COVID-19 are not well described. Objective: We sought to evaluate the incidence and predictive factors of cardiovascular complications and new-onset arrhythmias in Black and White hospitalized COVID-19 patients and determine the impact of new-onset arrhythmia on outcomes. Methods: We collected and analyzed baseline demographic and clinical data from COVID-19 patients hospitalized at the Tulane Medical Center in New Orleans, Louisiana, between March 1st and May 1st, 2020. Results: Among 310 hospitalized COVID-19 patients, the mean age was 61.4 ± 16.5 years, with 58,7% females, and 67% Black patients. Black patients were more likely to be younger, have diabetes and obesity . The incidence of cardiac complications was 20%, with 9% of patients having new-onset arrhythmia. There was no significant difference in cardiovascular outcomes between Black and White patients. D-dimer levels positively correlated with cardiac and new-onset arrhythmic event . New onset atrial arrhythmias predicted in-hospital mortality (OR=2.99 95% CI [1.35;6.63], p=0.007), a longer intensive care unit length of stay (mean of 6.14 days, 95% CI [2.51;9.77], p=0.001) and mechanical ventilation duration(mean of 9.08 days, 95% CI [3.75;14.40], p=0.001). Conclusion: Our results indicate that new onset atrial arrhythmias are commonly encountered in COVID-19 patients and can predict in-hospital mortality. Early elevation in D-dimer in COVID-19 patients is a significant predictor of new onset arrhythmias. Our finding suggest continuous rhythm monitoring should be adopted in this patient population during hospitalization to better risk stratify hospitalized patients and prompt earlier intervention.