Nair, Devi G

Introduction: The combination of local impedance (LI), a direct measure of electrical resistance at the catheter tip, and contact force (CF) may facilitate treatment of atrial fibrillation (AF). This trial is designed to examine the safety and effectiveness of a novel RF catheter that allows measurement of both LI and CF. Hypothesis: Demonstrate the safety and effectiveness of a novel radiofrequency catheter with LI and CF for treatment of drug refractory, recurrent, symptomatic Paroxysmal AF (PAF). Methods: NEwTON AF is a multi-center, global, prospective, single arm study. Patients received index treatment for PAF with the study catheter. The present 6-month endpoint analysis was prospectively planned. Results: The study treated 299 patients at 45 sites in North America, Europe, and Asia. Patients were 39.5% female with a mean age of 62yrs (±12), and had a mean LVEF of 59% and an LA diameter of 3.9cm. Procedure time, LA dwell, and fluoroscopy times were 166, 136, and 15 minutes, respectively. High-power short-duration (HSPD, 45-50W) was exclusively used in 210 cases, which had notably shorter procedure times than the 82 cases that used conventional power, 148 vs 208 min, respectively. Acute procedural success was observed in 98.3% of cases. As of 6 months, freedom from documented recurrence of any atrial arrhythmia was 79.9% (Figure). Recurrence in relation to LI shows that pts with a 20Ω LI drop (in at least 60% of lesions) had better 6m outcomes (84.2% vs 73.3, p=0.04). The freedom from safety event rate at 30d was 96.0%; events included pericarditis (6), access complications (2), pulmonary edema (2), embolism (2), cerebrovascular accident (1), tamponade (1). Pericarditis was higher in pts with a history of COVID at enrollment, 16.3% vs 5.9%, p=0.025. Conclusions: This data suggests that patient outcomes and safety for this novel catheter are promising. Further data from this study, including 12m outcomes, and detailed analysis of local impedance data are forthcoming.

Background The PINNACLE FLX (Protection Against Embolism for Non‐valvular AF [Atrial Fibrillation] Patients: Investigational Device Evaluation of the Watchman FLX LAA [Left Atrial Appendage] Closure Technology) trial evaluated the safety and efficacy of a next‐generation left atrial appendage closure device (WATCHMAN FLX; Boston Scientific, Marlborough, MA). At 1 year, the study met the primary end points of safety and anatomical efficacy/appendage closure. This final report of the PINNACLE FLX trial includes the prespecified secondary end point of ischemic stroke or systemic embolism at 2 years, also making it the first report of 2‐year outcomes with this next‐generation left atrial appendage closure device. Methods and Results Patients with nonvalvular atrial fibrillation with CHA 2 DS 2 ‐VASc score ≥2 (men) or ≥3 (women), with an appropriate rationale for left atrial appendage closure, were enrolled to receive the left atrial appendage closure device at 29 US centers. Adverse events were assessed by an independent clinical events committee, and imaging was assessed by independent core laboratories. Among 395 implanted patients (36% women; mean age, 74 years; CHA 2 DS 2 ‐VASc, 4.2±1.5), the secondary efficacy end point of 2‐year ischemic stroke or systemic embolism was met, with an absolute rate of 3.4% (annualized rate, 1.7%) and an upper 1‐sided 95% confidence bound of 5.3%, which was superior to the 8.7% performance goal. Two‐year rates of adverse events were as follows: 9.3% all‐cause mortality, 5.5% cardiovascular death, 3.4% all stroke, and 10.1% major bleeding (Bleeding Academic Research Consortium 3 or 5). There were no additional systemic embolisms, device embolizations, pericardial effusions, or symptomatic device‐related thrombi after 1 year. Conclusions The secondary end point of 2‐year stroke or systemic embolism was met at 3.4%. In these final results of the PINNACLE FLX trial, the next‐generation WATCHMAN FLX device demonstrated favorable safety and efficacy outcomes.

Despite the global COVID-19 pandemic, during the past 2 years, there have been numerous advances in our understanding of arrhythmia mechanisms and diagnosis and in new therapies. We increased our understanding of risk factors and mechanisms of atrial arrhythmias, the prediction of atrial arrhythmias, response to treatment, and outcomes using machine learning and artificial intelligence. There have been new technologies and techniques for atrial fibrillation ablation, including pulsed field ablation. There have been new randomized trials in atrial fibrillation ablation, giving insight about rhythm control, and long-term outcomes. There have been advances in our understanding of treatment of inherited disorders such as catecholaminergic polymorphic ventricular tachycardia. We have gained new insights into the recurrence of ventricular arrhythmias in the setting of various conditions such as myocarditis and inherited cardiomyopathic disorders. Novel computational approaches may help predict occurrence of ventricular arrhythmias and localize arrhythmias to guide ablation. There are further advances in our understanding of noninvasive radiotherapy. We have increased our understanding of the role of His bundle pacing and left bundle branch area pacing to maintain synchronous ventricular activation. There have also been significant advances in the defibrillators, cardiac resynchronization therapy, remote monitoring, and infection prevention. There have been advances in our understanding of the pathways and mechanisms involved in atrial and ventricular arrhythmogenesis.

Background: Left atrial appendage (LAA) occlusion provides an alternative to oral anticoagulation for thromboembolic risk reduction in patients with nonvalvular atrial fibrillation. Since regulatory approval in 2015, the WATCHMAN device has been the only LAA closure device available for clinical use in the United States. The PINNACLE FLX study (Protection Against Embolism for Nonvalvular AF Patients: Investigational Device Evaluation of the Watchman FLX LAA Closure Technology) evaluated the safety and effectiveness of the next-generation WATCHMAN FLX LAA closure device in patients with nonvalvular atrial fibrillation in whom oral anticoagulation is indicated, but who have an appropriate rationale to seek a nonpharmaceutical alternative. Methods: This was a prospective, nonrandomized, multicenter US Food and Drug Administration study. The primary safety end point was the occurrence of one of the following events within 7 days after the procedure or by hospital discharge, whichever was later: death, ischemic stroke, systemic embolism, or device- or procedure-related events requiring cardiac surgery. The primary effectiveness end point was the incidence of effective LAA closure (peri-device flow ≤5 mm), as assessed by the echocardiography core laboratory at 12-month follow-up. Results: A total of 400 patients were enrolled. The mean age was 73.8±8.6 years and the mean CHA 2 DS 2 -VASc score was 4.2±1.5. The incidence of the primary safety end point was 0.5% with a 1-sided 95% upper CI of 1.6%, meeting the performance goal of 4.2% ( P <0.0001). The incidence of the primary effectiveness end point was 100%, with a 1-sided 95% lower CI of 99.1%, again meeting the performance goal of 97.0% ( P <0.0001). Device-related thrombus was reported in 7 patients, no patients experienced pericardial effusion requiring open cardiac surgery, and there were no device embolizations. Conclusions: LAA closure with this next-generation LAA closure device was associated with a low incidence of adverse events and a high incidence of anatomic closure. Registration: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02702271.