Clinical course of hypertrophic cardiomyopathy in a regional United Statescohort

Context Hypertrophic cardiomyopathy (HCM) has been regarded as a disease th at causes substantial disability, with annual mortality rates of up to 6%, based largely on reports from tertiary referral centers. Objective To assess the clinical course of HCM in a patient cohort more clo sely resembling the true disease state. Design Retrospective cohort study. Setting A regional cohort from Minnesota and adjoining regions, free of ref erral center bias, studied at Minneapolis Heart Institute. Patients Two hundred seventy-seven consecutively studied HCM patients, none referred for specialized HCM care, managed clinically in a standard fashio n. Main Outcome Measures Mortality and clinical course of HCM. Results During a mean (SD) follow-up of 8.1 (6.6) years, 45 patients died a nd 29 of these deaths were directly related to HCM; however, 8 of the 29 HC M deaths were not premature (occurring >75 years of age). Annual HCM mortal ity rate was 1.3% (0.7% for sudden cardiac death). Patients identified in a dulthood (n = 234) showed no statistically significant difference in mortal ity when compared with expected mortality, as calculated for the general US or Minnesota populations (P = .17). Patients identified as children (n = 4 3) showed decreased survival compared with the general population (P < .001 ). At most recent clinical evaluation, 192 patients (69%) had no or mild sy mptoms and 69 (25%) experienced incapacitating symptoms or HCM-related deat h; 53 (19%) of the patients had achieved estimated life expectancy of 75 ye ars or older. More advanced symptoms at diagnosis-occurrence of atrial fibr illation (often associated with stroke), the presence of basal outflow obst ruction of at least 30 mm Hg, and marked left ventricular wall thickness of more than 25 mm-were clinically important independent predictors of HCM mo rtality. Conclusions In a regionally selected patient population most closely resemb ling the true disease state, HCM did not significantly increase the risk of premature death or adversely affect overall life expectancy. Prevailing mi sconceptions of HCM as a generally unfavorable condition may largely be rel ated to the skewed patient referral patterns characteristic of tertiary car e centers. Hypertrophic cardiomyopathy is nevertheless a highly complex dis ease capable of serious clinical consequences and premature death in some p atients.