Hypertrophic cardiomyopathy in Tuscany: clinical course and outcome in an unselected regional population.

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.