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.