Effect of biventricular pacing on symptoms and cardiac remodelling in patients with end-stage hypertrophic cardiomyopathy

Background: Biventricular (BiV) pacing is an established therapy for heart failure in ischaemic and dilated cardiomyopathy. Its effects in end-stage hypertrophic cardiomyopathy (HCM) are unknown. Aims: To assess the potential benefits of BiV pacing in patients with symptomatic end-stage HCM. Methods: Twenty patients with non-obstructive HCM (12 male, mean age 57 +/- 13 years), left bundle branch block and symptoms of heart failure refractory to medical therapy underwent implantation of a BiV device. NYHA class, echocardiographic parameters and exercise capacity were assessed before and after implantation. Results: At a mean follow-up of 13 +/- 6 months, an improvement of at least one NYHA class was reported in 8 (40%) patients. A clinical response was associated with an increase in ejection fraction (from 41 +/- 14% to 50 +/- 12%, p=0.009), and reductions in left ventricular end-diastolic diameter (from 57 +/- 6 turn to 52 +/- 7 mm, p=0.031) and left atrial diameter (from 65 +/- 8 min to 57 +/- 6 mm, p=0.005). Percentage predicted peak oxygen consumption was unchanged in responders but significantly declined in non-responders (p=0.029). Conclusions: BiV pacing improved heart failure symptoms in a significant proportion of patients with end-stage HCM. Symptomatic improvement was associated with reverse remodelling of the left atrium and ventricle. (C) 2008 Published by Elsevier B.V. on behalf of European Society of Cardiology.