Effect of trimetazidine dihydrochloride therapy on myocardial external efficiency in preclinical individuals with an HCM sarcomeric gene mutation

Abstract Background Hypertrophic cardiomyopathy (HCM) is frequently caused by pathogenic gene variants, i.e. mutations in genes encoding sarcomere proteins. Previous studies have shown that preclinical asymptomatic individuals with a heterozygous sarcomere mutation have decreased myocardial external efficiency (MEE), which is thought to be a key pathomechanism in the onset and progression of HCM. Purpose In the ENERGY trial, preclinical individuals with an HCM sarcomere gene mutation without hypertrophy were treated with the metabolic anti-anginal drug trimetazidine (TMZ) to determine whether the reduced MEE can be corrected at an early pre-hypertrophic disease stage. Methods 40 MYBPC3 and MYH7 asymptomatic mutation carriers without hypertrophy were treated for eight weeks with TMZ or placebo in a double-blind randomized study design. Directly before and after treatment, study participants underwent an [11C]-acetate PET/CT-scan and cardiac magnetic resonance imaging to measure MEE. A cardio-pulmonary exercise test was performed to measure the influence of TMZ on exercise parameters. Results Eight weeks of treatment with TMZ 20mg three times daily did not significantly alter MEE compared to placebo. The mean MEE changed from 30.3±3.8 percent to 29.8±4.3 percent in the placebo group and from 30.1±4 percent to 29.1±4 percent in the TMZ group. After adjustment for baseline, the TMZ group did not have a significantly different MEE (95% CI, -2.863 to 1.986, P=0.68) compared to placebo. Exercise parameters VO2max and respiratory exchange ratio were not significantly altered by treatment with TMZ. Conclusion The ENERGY trial is the first proof-of-concept randomized controlled trial with well-matched (age, sex, mutation) groups to test the hypothesis that TMZ improves MEE at a preclinical disease stage. We conclude that metabolic therapy does not correct reduced MEE in an early disease stage of HCM.methodsprimary outcome