The ABLATE Trial: Safety and Efficacy of Cox Maze-IV Using a Bipolar Radiofrequency Ablation System

Background: The Cox Maze-IV procedure (CMP-IV) has replaced the Cox Maze-III procedure as the most common approach for the surgical treatment of atrial fibrillation (AF). The Food and Drug Administration-regulated AtriCure Bipolar Radiofrequency Ablation of Permanent Atrial Fibrillation (ABLATE) trial sought to demonstrate the safety and efficacy of the CMP-IV performed with the Synergy ablation system (AtriCure, Inc, Cincinnati, OH).

Methods: Fifty-five patients (aged 70.5 ± 9.3 years), 92.7% of whom had nonparoxysmal AF, underwent CMP-IV to terminate AF during a concomitant cardiac surgical procedure. Lesions were created using the AtriCure Synergy bipolar radiofrequency ablation system. All patients were seen for follow-up visits after 30 days, 3 months, and 6 months, with 24-hour Holter monitoring at 6 months. Late evaluation was performed by 48-hour Holter monitoring at an average of 21 months.

Results: The primary efficacy endpoint, absence of AF (30 seconds or less) at 6-month follow-up off antiarrhythmic medications (Heart Rhythm Society definition), indicated 76% (38 of 50) were AF free (95% confidence interval: 62.6% to 85.7%). The primary safety endpoint, the rate of major adverse events within 30 days, was 9.1% (5 of 55; 95% confidence interval: 3.9% to 19.6%), with 3.6% mortality (2 of 55). Secondary efficacy endpoints included being AF free with antiarrhythmic drugs (6 months, 84%; 21 months, 75%), successful pulmonary vein isolation (100%), and AF burden at 6 and 21 months. The results, together with those for the secondary safety endpoint (6-month major adverse events), demonstrated that the Synergy system performs comparably to the cut-and-sew Cox Maze-III procedure.

Conclusions: The CMP-IV using the AtriCure Synergy system was safe and effective for cardiac surgical patients who had persistent and longstanding persistent AF.