Surgical ablation of atrial fibrillation in hypertrophic obstructive cardiomyopathy: Outcomes of a tailored surgical approach.

OBJECTIVE

To assess outcomes of concomitant ablation for atrial fibrillation (AF) in patients with preoperative AF undergoing septal myectomy for hypertrophic obstructive cardiomyopathy.

METHODS

From 2005 to 2016, 67 patients underwent concomitant ablation for AF and septal myectomy and had a follow-up beyond a 3-month blanking period. Ablation strategy (pulmonary vein isolation [PVI], modified Cox-maze III [CM-III], or Cox-maze IV [CM-IV]) was tailored to preoperative AF burden, with high AF burden defined as persistent AF or need for cardioversion. AF recurrence was analyzed as a time-related event and predictors of recurrence identified using a random forest methodology.

RESULTS

A total of 38 patients (57%) had low AF burden and 29 (43%) high burden. Patients with low AF burden most frequently underwent PVI (68%). Patients with high AF burden more frequently underwent CM-III (62%) or CM-IV (35%). Besides the preoperative AF burden, baseline characteristics were similar between patients receiving CM-III, CM-IV, and PVI. After surgery, the maximum provoked left ventricular outflow tract (LVOT) gradient decreased from 99 ± 34 to 18 ± 11mm Hg (P < .001). Eight patients (12%) required a permanent pacemaker. Cumulative AF recurrence at 1, 2, and 5 years was 11%, 22%, and 48%, respectively. Age, low preoperative resting LVOT gradient, and large left atrial diameter were predictors of AF recurrence.

CONCLUSIONS

Surgical outcomes of concomitant ablation for AF and septal myectomy are good, although recurrence of AF by 5 years is frequent.