Efficacy of Combined Cox-Maze IV and Ventricular Septal Myectomy for Treatment of Atrial Fibrillation in Patients With Obstructive Hypertrophic Cardiomyopathy.

Atrial fibrillation (AF) has important clinical consequences in hypertrophic cardiomyopathy (HC). Safety and efficacy of the Cox-Maze IV procedure (when combined with ventricular septal myectomy) in patients with obstructive HC and paroxysmal AF is largely unresolved. Records of 395 consecutive HC patients (age 55 ± 13 years) who underwent septal myectomy for heart failure symptoms between 2004 and 2015 were reviewed. Sixty-two patients also had concomitant complete biatrial Cox-Maze IV for a history of symptomatic paroxysmal AF (3.0 ± 3.6 episodes) combined with myectomy comprise the study cohort. Freedom from symptomatic AF recurrences after operation was assessed. Left ventricular outflow gradients were reduced from 81 ± 28 mm Hg preoperatively to 1.2 ± 6.8 mm Hg after operation. At most recent follow-up, 53 patients (85%) were asymptomatic or mildly symptomatic. Freedom from recurrent symptomatic AF after myectomy/Cox-Maze IV was: 85% (95% confidence interval [CI] 73, 92) at 1 year, 69% (95% CI 55, 79) at 3 years, and 64% (95% CI 48, 75) at 5 years, including 34 patients (54%) who have experienced no symptomatic AF episodes for up to 8.2 years following surgery. The only clinical predictor of recurrent AF over follow-up was preoperative transverse left atrial dimension ≥45 mm (p <0.01). In conclusion, biatrial Cox-Maze IV combined with septal myectomy is associated with favorable long-term freedom from symptomatic paroxysmal AF recurrence, as well as from obstructive heart failure symptoms. These data support myectomy/Cox-Maze as an effective management option for the subgroup of HC patients with symptomatic outflow obstruction and paroxysmal AF.