[Familial hypertrophic myocardiopathy: complex ventricular arrhythmias in healthy family members]

Abstract

The aim of the present study was to evaluate the electrocardiographic changes among the members of a family affected by hypertrophic cardiomyopathy. Seventeen unaffected members and 8 affected members were studied by 24-hour Holter monitoring. Twenty-five normal controls were also studied by 24-hour Holter monitoring. One out of 7 (12.5%) patients with hypertrophic cardiomyopathy, 8 out of 17 (47%) unaffected relatives and 20 out of 25 (80%) controls did not show ventricular arrhythmias. One out of 7 patients (12.5%), 4 out of 17 (23.5%) unaffected relatives and 3 out of 25 (12%) of the control group showed Lown classes I-II ventricular arrhythmias. Complex ventricular arrhythmias (III-V Lown classes) were detected in 5/7 (71.4%) of patients, in 5/17 (29.5%) of unaffected members and only in 2/25 (8%) of the normals. Among the unaffected members we compared the prevalence of complex ventricular arrhythmias between the offspring of patients with that of the unaffected first-grade relatives. Three out 7 (43%) of the offspring of the patients showed complex ventricular arrhythmias and none among the offspring of normal first-grade relatives showed such arrhythmias. Neither the patients nor their relatives in this study showed any significant ST segment changes during the 24-hour Holter monitoring. We suggest that in first-grade relatives of patients with familial hypertrophic cardiomyopathy, complex ventricular arrhythmias could be a marker of latent disease, without clinical and echocardiographic manifestations.