Cardiac pacing in hypertrophic cardiomyopathy: a cohort with 24 years of follow-up.

BACKGROUND The benefits of heart stimulation in hypertrophic cardiomyopathy (HCM) patients have been questioned. Research work available in Brazil on those benefits is scarce. OBJECTIVE To describe the indication, clinical response, complications and survival time related to pacemaker implant in HCM patients. METHODS Thirty-nine hypertrophic cardiomyopathy patients were studied (41% males) and submitted to pacemaker implant from May, 1980 through November, 2003. RESULTS Twenty-seven patients presented obstructive hypertrophic cardiomyopathy, and 12, non-obstructive. Mean age was 46.4 years of age (range 14-77), with follow-up of 6.4+/-4.1 years. Major indications for implant were: spontaneous or induced atrioventricular block (54%), refractoriness to therapeutic conduct associated to high gradient (33%), support for drug therapy to treat bradychardia (8%), and atrial fibrillation prevention (5%). Functional class was shown to improve from 2.41+/-0.87 to 1.97+/-0.92 (p=0.008), and symptoms referred were reduced. No change was made in drug therapy administration. No procedure-related deaths were reported. Although shown to be safe, the procedure was not free from complications (6 patients--15.4%). Three deaths occurred in the follow-up period--the three of them were atrial fibrillation female patients, with evidence of functional deterioration. A close association was observed between clinical condition worsening and the onset of atrial fibrillation or flutter. CONCLUSION Cardiac pacing in HCM patients was successful, with evidence of symptoms relief in obstructive HCM patients. No functional improvement was observed in non-obstructive patients.