Radiofrequency septal reduction in symptomatic hypertrophic obstructive cardiomyopathy

Abstract

Background: Alcohol septal ablation remains the only approved nonsurgical therapeutic alternative for patients with drug-resistant hypertrophic obstructive cardiomyopathy (HOCM). Radiofrequency (RF) ablation offers another option for treating HOCM.

Objective: The purpose of this study was to determine whether irrigated RF ablation can reduce symptomatic outflow tract obstruction in adults with HOCM.

Methods: Patients with symptomatic HOCM and an outflow gradient of >50 mm Hg despite medication were offered RF ablation. In 11 patients, the hypertrophied interventricular septum was localized on a 3-dimensional mapping system and ablated via a transmitral or retrograde aortic approach.

Results: Ten of 11(91%) patients had a significant and persistent reduction in resting and provocable left ventricular outflow tract gradients. Mean resting gradients at 12 months postprocedure were reduced by 85% (66.7 mm Hg at baseline to 10.0 mm Hg at 12 months); mean provocable gradients were reduced by 85% from baseline (136.2 mm Hg at baseline to 20.0 mm Hg at 12 months). Functional New York Heart Association heart classification improved from class 3.0 ± 0.0 in all patients to class mean of 1.8 ± 0.8.

Conclusion: RF septal ablation for the treatment of HOCM is a safe therapeutic option that allows for significant reduction in left ventricular outflow tract gradients, improvement in symptoms, and increase in efficacy rates comparable to reported rates for alcohol septal ablation.

Keywords: Ablation; Hypertrophic obstructive cardiomyopathy; Interventricular septum; Left ventricular outflow tract; Radiofrequency.