Abstract 3350: Impact of Genetic Screening on the Development to End-Stage Phase in Hypertrophic Cardiomyopathy: From the Comparison of Clinical Course in Carriers With Thick Filament Mutations and Thin Filament Mutations
Background: Hypertrophic cardiomyopathy (HCM) is recognized to be a disease of sarcomere and approximately 5% of cases develop to end-stage phase with decreased left ventricular contractility. However, few data exist regarding the differences in clinical course to end-stage HCM among carriers with different gene mutations. Therefore, we compared the clinical course to end-stage HCM between mutation carriers with thick-filament gene (MYH7 and MYBPC3: Group-Thick) and those with thin-filament gene (TNNT2 and TNNI3: Group-thin).
Methods and Results: The study comprised of 146 HCM patients with sarcomere gene mutations (17 with MYH7, 54 with MYBPC3, 22 with TNNT2, and 53 with TNNI3), which were determined by PCR-SSCP or direct sequence. We compared echocardiographic parameters and cardiac event defined by the development to end-stage phase (%fractional shortening: FS <25%). There were 71 HCM patients in Group-Thick (mean age 53.9 +/− 18.5) and 75 in Group-thin (44.8 +/− 20.5, P<0.05). At the time of enrollment, no differences were found in interventricular septal wall thickness (16.4 +/− 5.4 mm vs.14.8 +/− 6.1 mm), left ventricular end-diastolic dimension (45.0 +/− 6.8 mm vs. 44.5 +/− 7.5 mm), and FS (28.3 +/− 7.7 % vs. 29.3 +/− 8.8 %), respectively, between Group-Thick and Group-thin. Interestingly, the age developing to end-stage phase was lower in Group-thin than in Group-Thick (Figure⇓, P<0.05).
Conclusions: These results demonstrate the differences in age developing to end-stage phase in HCM between patients with thick- and those with thin-filament mutations. We suggest performing earlier medical intervention such as beta-blockers in HCM with thin-filament gene mutations.