Historical trends in reported survival rates in patients with hypertrophic cardiomyopathy

Objective: To determine the range of survival rates of patients with hypertrophic cardiomyopathy (HCM) by comparing and contrasting the natural history of a cohort of patients seen between 1988 and 2002 with that of other published series. Methods: 956 adult (>= 16 years old) patients with HCM (572 men, mean (SD) age 42 ( 15) years, range 16-88) were evaluated by ECG, Holter, exercise testing, and echocardiography. Patient characteristics and survival data were compared with those in natural history studies from referral and non-referral centres published between 1960 and January 2003. Results: The duration of follow up was 69 ( 45) months. 120 (12.6%) patients died or underwent cardiac transplantation. Sudden cardiac death (n = 48) was the most common mode of death. The annual rate of sudden death or implantable cardioverter-defibrillator discharge was 1.02 (95% confidence interval (CI) 0.76 to 1.26). Annual rates for heart failure death or transplantation and stroke related death were 0.55% ( 95% CI 0.37% to 0.78%) and 0.07% ( 95% CI 0.02% to 0.19%), respectively. When studies published within the last 10 years of the study period were compared with earlier reports, the size of individual study cohorts was larger (309 (240.6) v 136.5 (98.8), p = 0.058) and the proportion with severe functional limitation NYHA class III/IV lower (12.4% v 24.8%, p < 0.0001), and fewer patients underwent septal myotomy-myectomy (5.2% v 18.7%, p < 0.0001). Published sudden death rates over the last 10 years were lower than previously published figures ( median 1.0% ( range 0.1-1.7) v 2.0% (0-3.5)). Conclusion: Published survival rates in HCM cohorts have improved progressively over the past 40 years. In the modern era the prevalence of disease related complications is similar in all reporting centres.