Objectives: Our aim was to study a population of patients with hypertrophic cardiomyopathy from the well defined geographic region of Tuscany in central Italy, a group virtually free of selective referral bias and therefore probably closely representative of the true patient population with this disease.
Background: Most available information on clinical course, natural history and prognosis of hypertrophic cardiomyopathy is based on data generated from tertiary referral centers and therefore constitutes a potentially biased perspective of the disease process in this complex and diverse condition.
Methods: The study group comprised 202 patients aged 1 to 74 years (mean +/- SD 41 +/- 17) at initial diagnosis and followed up for 1 to 30 years (mean 10 +/- 5).
Results: Largely with the use of single or multiple drug therapy, the vast majority of patients (n = 154 [76%]) were asymptomatic or mildly symptomatic and in stable or improved condition over the period of follow-up, whereas the remaining patients (n = 48 [24%]) experienced deterioration, had substantial functional impairment or died. Of the 13 patients (6%) who died of cardiovascular causes related to hypertrophic cardiomyopathy, 11 had progressive congestive heart failure (including 6 in the end-stage phase) and only 2 died suddenly. The annual mortality rate for cardiovascular disease was 0.6% and that due to sudden cardiac death was only 0.1%; the cumulative survival rate was 97%, 95% and 92%, respectively, at 5, 10 and 15 years of follow-up. Atrial fibrillation proved to be a relatively common (n = 57 [28%]) and particularly unfavorable clinical feature, with premature death occurring in 9 of the 57 patients. The cumulative survival rate after 15 years was 76% for patients with atrial fibrillation versus 97% for patients with sinus rhythm. Syncope occurred in 33 patients (16%) but did not appear to be of prognostic significance.
Conclusions: In an unselected regional population, hypertrophic cardiomyopathy had a relatively benign prognosis inconsistent with its prior characterization as a generally progressive disorder, based primarily on the experience of selected referral institutions. Sudden unexpected cardiac death was distinctly uncommon, although a sizable proportion of patients (particularly the subset prone to atrial fibrillation), did experience clinical deterioration.