Early and late outcome after microwave ablation for chronic valvular atrial fibrillation

Microwave energy ablation is one of the newer therapeutic options for surgically treating patients with chronic atrial fibrillation (AF) concomitant with mitral valve disease. The aim of this study was to retrospectively evaluate potential risk factors that may have influenced early as well as remote outcome in a set of patients undergoing microwave energy ablation for chronic AF.

Patients (n = 42) underwent ablation on an arrested heart concomitant with mitral valve surgery. Twelve patients also underwent tricuspid valve repair or replacement. Logistic regression analyses were performed to evaluate effect of potential risk factors on postablation rhythm status at discharge and at latest follow-up examination.

With control for age, patients with recurrent AF at discharge (10/42 [24%]) tended to have preoperative AF of significantly longer duration (odds ratio [OR], 1.64; 95% confidence interval [CI], 1.15-2.35; P = .01) and greater left atrial diameter (OR, 1.14; 95% CI, 1.03-1.26, P = .01) than patients in sinus rhythm (32/42 [76%]). At latest follow-up examination, risk of AF was significantly heightened with longer duration of preoperative AF (OR, 1.47; 95% CI, 1.09-1.96; P = .01) and larger left atrium (OR, 1.12; 95% CI, 1.02-1.23; P = .02) after adjustment for age, length of follow-up time, and presence of early arrhythmia recurrence.

Results for this consecutive series of patients indicated that early and late success after surgical energy ablation may be associated with discrete patient characteristics. Longer arrhythmia duration and greater left atrial diameter seem to be factors independently influencing early and remote success, and there seems to be a self-protective effect of the presence of sinus rhythm at discharge. Further study would be valuable to confirm our findings.