Background: Balloon catheters facilitate pulmonary vein (PV) isolation, but current technology is limited by either a single ablative element, potentially leading to over-ablation of thin and under-ablation of thick tissue, or prolonged procedure times. Visualized by electroanatomical mapping, a novel compliant radiofrequency balloon catheter with 10 irrigated, flexible electrodes can simultaneously and independently deliver energy. Herein, we evaluated the feasibility, safety, and short-term efficacy of this radiofrequency balloon in a multicenter, single-arm, first-in-human study.
Methods: Paroxysmal atrial fibrillation patients underwent PV isolation with the radiofrequency balloon delivered over-the-wire with a deflectable 13.5F sheath. Radiofrequency energy is delivered simultaneously from all electrodes-up to 30 s posteriorly and 60 s anteriorly. Esophageal temperature was monitored in all patients; the esophagus was also mechanically deviated in 10 patients.
Results: At 4 sites, 39 patients were treated by 9 operators. The radiofrequency balloon isolated all targeted PVs (152/152), 79.6% with a single application. Electrical reconnection occurred in only 7/150 PVs (4.7%) on adenosine/isoproterenol challenge. Mean procedure, balloon dwell, and fluoroscopy times were 101.6, 40.5, and 17.4 min, respectively. Esophagogastroduodenoscopy revealed asymptomatic esophageal erythema in 5 patients. Phrenic nerve palsy occurred in a patient in whom phrenic pacing was inadvertently omitted. At 3 months, imaging revealed no PV stenosis, and early atrial arrhythmia recurrence occurred in only 10/39 (25.6%) patients.
Conclusions: The compliant radiofrequency balloon can directionally tailor energy delivery for efficient, effective, and reasonably safe acute PV isolation.
Clinical trial registration: URL: https://www.clinicaltrials.gov. Unique identifier: ISRCTN 11764506.
Keywords: atrial fibrillation; catheter ablation; esophagus; multielectrodes; pulmonary veins.