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 mm to 52+/-7 mm, p=0.031) and left atrial diameter (from 65+/-8 mm 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.