Radiofrequency Ablation in Patients Undergoing Mitral Valve Surgery with or without Giant Left Atria

Purpose: We aimed to compare the efficacy of radiofrequency ablation (RFA) in patients undergoing mitral valve (MV) surgery with or without giant left atria. Methods: This retrospective, single-center, cohort study investigated patients who underwent MV surgery and concomitant RFA from 2009 to 2019. Patients were divided into non-giant left atria (diameter ≤65 mm, n = 1543) and giant left atria (diameter >65 mm, n = 241) groups. Five-year freedom from atrial tachyarrhythmia recurrence and thromboembolic event (TE) rates were assessed with death as the competing risk factor with and without propensity-score matching. Results: Patients with giant left atria had higher mortality (10.8% versus 6.2%, P = 0.008) and readmission rates for heart failure than those without (12.0% versus 6.8%, P = 0.004). Atrial tachyarrhythmia recurrence rates were higher in patients with giant left atria than in those without (49% versus 24% at 5 years, P <0.001), but the cumulative incidence of TEs before (P = 0.944) and after (P = 0.695) propensity-score matching was comparable. Conclusions: RFA effectively prevented TEs in patients with giant left atria, despite significant atrial tachyarrhythmia recurrence. Atrial tachyarrhythmia recurrence did not increase the risk of TEs. A lower success rate should be considered when deciding whether to perform surgical ablation in patients with giant left atria.