Ultrasonic cardiac ablation for atrial fibrillation during concomitant cardiac surgery: long-term clinical outcomes.

Background: Therapeutic ultrasound as an alternative to the maze procedure was evaluated in this large US experience. Safety and efficacy were assessed at 6-, 12-, and 18-month visits with systematic 24-hour Holter monitoring.

Methods: From February 2005 to February 2007, 220 patients were prospectively enrolled in a single center study, and among them 129 patients with concomitant cardiac surgery and at least 6-month follow-up were reviewed. Primary procedures were mitral surgery in 50% of the cases, coronary bypass in 32%, and aortic surgery in 16%. Atrial fibrillation was permanent in 66 (51.1%), paroxysmal in 43 (33.3%), and persistent in 20 (15.5%) patients. An epicardial and circumferential left atrial encircling line was created on the beating heart. Routinely a mitral isthmus line was also created from the left atrium epicardium using an ultrasonic handheld device.

Results: No morbidity or mortality was device-related. There were four (2.33%) early deaths and six late extra-cardiac deaths. Follow-up ranged from 6 to 670 days with a mean follow-up of 358.5 days, median 340 days with two patients lost to follow-up. Freedom from atrial fibrillation or left-sided flutter was 83.2%, 84.4%, and 86.2% at 6, 12, and 18 months, respectively. A pacemaker was implanted in seven patients (5.4%). Male gender and left atrial dimension were significant risk factors for failure.

Conclusions: The study confirms the excellent safety record of the technology, and the efficacy at the level reported in a previous European multicenter study. Efficacy is also maintained at longer (12 and 18 months) follow-up.