The prevalence of hypertrophic cardiomyopathy in men: an echocardiographic population screening study with a review of death records

The purpose of this study was to estimate the prevalence of hypertrophic cardiomyopathy (HCM) in 3607 men from the Reykjavik study of 1979-81. Of these, 452 men had an abnormal (group A) and 3155 a normal electrocardiogram. An echocardiographic control group of 128 men was selected from cohorts with a normal electrocardiogram (group B). Until 1987, 189 deaths had occurred, 59 from group A and 130 from cohorts with a normal ECG including 4 from group B. To identify subjects with HCM, survivors of groups A and B were examined by echocardiography and by review of all autopsy data and death certificates. HCM was found in 14 subjects from group A but none in group B. Two additional cases were found at autopsy in cohorts with a normal ECG. The prevalence of HCM in men with an abnormal and normal ECG was 3.6% and 0.8%, respectively. The overall prevalence was calculated to be 1.1% with a 95% confidence interval of 0.3-3.2%. Men with HCM reported more symptoms than others in groups A and B (P < 0.05-0.001). 25% were without symptoms. Asymptomatic ventricular arrhythmias were detected by Holter monitoring in 45% of men with HCM. The total annual mortality was 1.6% compared with 0.5% in the group with a normal ECG (P < 0.001).