Concomitant Cox-Maze IV and Septal Myectomy in Patients with Hypertrophic Obstructive Cardiomyopathy.

BACKGROUND In patients with hypertrophic obstructive cardiomyopathy, atrial fibrillation is associated with heart failure and increased late mortality. However, the role of surgical ablation in these patients is not well-defined. The aim of this study was to evaluate the efficacy of the concomitant Cox-Maze IV procedure in patients undergoing septal myectomy for hypertrophic obstructive cardiomyopathy. METHODS Between 2005-2019, 347 patients who underwent septal myectomy at our institution were retrospectively reviewed. For patients with hypertrophic obstructive cardiomyopathy and atrial fibrillation who underwent concomitant Cox-Maze IV, freedom from atrial tachyarrhythmias(ATAs) on/off antiarrhythmic drugs(AADs) was evaluated annually. Predictors of ATAs recurrence were identified using Fine-Gray regression with death as a competing risk. RESULTS Forty-two patients underwent concomitant septal myectomy and Cox-Maze IV. The majority of patients, 69%(29/42), had paroxysmal atrial fibrillation with a 2.5 year median duration. Operative mortality was 7%(3/42). New York Heart Association class was reduced after surgery(P<0.01). Freedom from recurrent ATAs at 1- and 5-year intervals were 93%(27/29) and 100%(14/14), respectively. Freedom from ATAs and AADs were 83%(24/29) and 100%(14/14) at the same timepoints. Increased left atrial diameter predicted first ATAs recurrence(P<0.01). Cerebrovascular accident risk was lower in patients with atrial fibrillation who underwent concomitant Cox-Maze IV and septal myectomy relative to myectomy only(P=0.02). CONCLUSIONS Late freedom from ATAs on/off AADs was excellent after Cox-Maze IV and septal myectomy. While there was a higher than expected rate of perioperative complications, our results suggest that concomitant surgical ablation should be considered in selected patients with hypertrophic obstructive cardiomyopathy and atrial fibrillation.