Maximum left ventricular thickness and risk of sudden death in patients with hypertrophic cardiomyopathy

OBJECTIVES: We sought to assess the relationship between maximum left ventricular (LV) wall thickness and outcome in patients with hypertrophic cardiomyopathy (HCM). BACKGROUND: An association between maximum LV wall thickness and risk of sudden death was suggested in HCM. This finding requires further investigation, given the important implications for risk stratification and treatment. METHODS: We analyzed the mortality and risk profile of 237 patients (age 41 +/- 17 years; 63% male) classified into five groups based on echocardiographic maximum LV thickness. RESULTS: During follow-up (12 +/- 7 years), 36 patients died of cardiovascular causes, including 16 sudden deaths. Maximum LV thickness was not associated with a risk of sudden death (p = 0.37) nor with overall cardiovascular mortality (p = 0.7). With the exception of the small subset with thickness values < or =15 mm, with a consistently benign clinical course, the distribution of sudden death and overall cardiovascular mortality was not significantly different among the other four classes, ranging from 16 to 19 mm to > or =30 mm. Among 30 patients with extreme LV thickness (> or =30 mm), only one sudden event occurred among six patients diagnosed at <18 years of age (17%) and none among 24 diagnosed at > or =18 years of age. The prevalence of nonsustained ventricular tachycardia, syncope, an abnormal blood pressure response to exercise, and atrial fibrillation was similar among the five thickness classes. CONCLUSIONS: During 12-year follow-up, we observed no association between maximum LV thickness and cardiovascular mortality in a community-based population with HCM. The degree of maximum LV wall thickness should be considered in the context of a multifactorial approach to risk stratification, rather than as an isolated risk factor. Only in those patients diagnosed at a very young age might the presence of extreme LV wall thickness represent, per se, a potential marker of risk of sudden death.