Multielectrode Radiofrequency Balloon Catheter for Paroxysmal Atrial Fibrillation: Results From the Global, Multicenter, STELLAR Study

Introduction: The safety and efficacy of paroxysmal atrial fibrillation (PAF) ablation with the HELIOSTAR multielectrode radiofrequency (RF) balloon catheter have been demonstrated in European studies; data from elsewhere are lacking. This prospective, multicenter study conducted in the United States, Italy, and China investigated the safety and efficacy of pulmonary vein isolation (PVI) using HELIOSTAR in drug-refractory symptomatic PAF. Methods: The primary effectiveness endpoint (PEE) was 12-month freedom from documented atrial fibrillation/atrial flutter/atrial tachycardia plus freedom from acute procedural failure, nonstudy catheter failure, repeat ablation failure, direct current cardioversion (DCCV), and Class I/III antiarrhythmic drug (AAD) failure. The primary safety endpoint was the occurrence of early-onset primary adverse events (PAEs). Cerebral magnetic resonance imaging (MRI) and cardiac computed tomography were performed in a patient subset to assess silent cerebral lesions (SCLs) and severe pulmonary vein (PV) stenosis, respectively. Results: Across 36 centers, 257 eligible subjects in the main phase had the study catheter inserted. Acute PVI was achieved in all subjects, with the majority (94.1%) using the balloon catheter only. In 67.7% and 92.2% of subjects, respectively, PEE and freedom from repeat ablation were met; clinical success rate was 77.7%. The PAE rate was 5.1%. One of 15 (6.7%) subjects with MRI showed a new SCL at 1 month postablation, which resolved at 3 months. Clinically meaningful improvements in Atrial Fibrillation Effect on QualiTy-of-life scores were seen at 3 months and were sustained to 12 months postablation, and accompanied with reduction of Class I/III AAD use and DCCV. Conclusion: STELLAR confirmed the safety and efficacy of the HELIOSTAR catheter for PVI, with clinically meaningful improvements in quality of life in patients with drug-refractory symptomatic PAF. Most PVIs were achieved without focal touch-up, and > 90% of patients were free from repeat ablation at 12 months.