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 less than or equal to15 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 greater than or equal to30 mm. Among 30 patients with extreme LV thickness (greater than or equal to30 mm), only one sudden event occurred among six patients diagnosed at <18 years of age (17%) and none among 24 diagnosed at >= 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.