Key Points:
- Persistent atrial fibrillation (AF) is common among patients with rheumatic mitral valve disease undergoing surgery, but the optimal surgical ablation strategy remains uncertain.
- In this multicenter randomized trial conducted in China, biatrial ablation during mitral valve surgery resulted in significantly higher rates of arrhythmia-free survival compared to left atrial ablation alone.
- Importantly, the biatrial approach did not increase the risk of permanent pacemaker implantation, meeting non-inferiority criteria for safety.
Atrial fibrillation is frequently encountered in patients undergoing mitral valve surgery (MVS), particularly those with rheumatic heart disease. Current guidelines recommend concomitant surgical ablation during MVS to improve rhythm control, but the optimal lesion set—left atrial (LA) only versus biatrial (BA), remains an open question. The ABLATION trial was designed to address this knowledge gap in patients with persistent AF undergoing rheumatic MVS.
The ABLATION trial (Bi-atrial vs Left Atrial Ablation for Patients with RMVD and Non-paroxysmal AF) is a prospective, multicenter, randomised controlled study. The study design was published in BMJ Open. The trial randomly assigned 323 patients with RMVD and persistent or long-standing persistent AF to bi-atrial ablation procedure or left atrial ablation procedure in a 1:1 randomization. The primary end point was freedom from documented AF, atrial flutter or atrial tachycardia of >30 s at 12 months after surgery off antiarrhythmic drugs. Key secondary end point was the probability of freedom from permanent pacemaker implantation at 12 months after surgery. Secondary outcomes included the probability of freedom from any recurrence of atrial tachyarrhythmias with antiarrhythmic drugs, AF burden, incidence of adverse events and cardiac function documented by echocardiography at 12 months after operation. The trial enrolled 323 patients from 20 centers in China, with a mean age of 56.5 years, 72% of whom were women. Participants with persistent AF referred for rheumatic MVS were randomized 1:1 to receive either biatrial (Cox Maze IV) or left atrial ablation. To ensure procedural consistency, all surgeons underwent centralized training and pre-trial certification, and all procedures were video recorded for quality assurance. Rhythm outcomes were assessed using scheduled Holter monitoring (24-hour at 3 months; 3-day at 6 and 12 months), supplemented by patient-triggered recordings.
At 12 months, freedom from atrial tachyarrhythmias without antiarrhythmic drugs was significantly higher in the biatrial group compared with the LA-only group (78.9% vs. 68.2%; absolute difference 10.7%; one-sided 95% CI 3.0 to ∞; p = 0.012). The secondary safety endpoint, freedom from permanent pacemaker implantation, was also met, with non-inferior outcomes in the BA group (97.0% vs. 98.1%; difference −1.1%; one-sided 95% CI −3.9 to ∞; p for non-inferiority = 0.011). Mortality during follow-up was low, with three deaths reported in each group and no loss of follow-up.
Presented on November 8, 2025, at the American Heart Association Scientific Sessions in New Orleans, Louisiana, by Dr. Zhe Zhang from Fuwai Hospital, Chinese Academy of Medical Sciences in Beijing China, this study supports a broader role for biatrial lesion sets in surgical ablation during rheumatic MVS and may influence future guideline recommendations for rhythm control in this high-risk population.