Does a More Extensive Lesion Set Improve Rhythm Control? Outcomes of Cryoablation During Mitral Valve Replacement

We evaluated whether complementary coronary sinus (CS) lesions improve rhythm outcomes beyond biatrial cryoablation during mitral valve replacement. This single-center cohort included 180 adults operated on by one senior surgeon between January 2020 and September 2025, with follow-up through May 2026. Left atrial ablation (LA-Abl; n=65), biatrial ablation (BA; n=63), and BA with complementary CS lesions (BA+CS; n=52) were compared. After excluding three early deaths and five patients without follow-up records, 172 patients underwent rhythm assessment. The primary outcome was time to first recorded atrial fibrillation (AF) after discharge. Seventeen AF events were recorded. The primary Cox estimate favored BA+CS over BA without statistical significance (hazard ratio [HR] 0.52; 95% confidence interval [CI] 0.12–2.15); the numerical trend persisted after adjustment for baseline clinical and echocardiographic burden and surgical year (HR 0.54; 95% CI 0.13–2.20). Larger left atrial diameter and lower ejection fraction were associated with AF. Twelve-month sinus rhythm rates were 86.9%, 91.7%, and 94.1%, respectively (p=0.459). Weighted estimates varied by method. Outcome sensitivity analyses showed no significant advantage. An incremental CS benefit was not established; limited events, nonrandomized selection, and intermittent monitoring warrant cautious interpretation and larger studies with standardized surveillance.