Study limitation
EVENTS
Our study has some limitations that should be addressed. First, because this was a single-center trial, the study population was less heterogeneous. Second, the sample size was lower than expected due to slow enrollment during covid-19, which resulted in the underpowered primary outcome analysis. Third, high discontinuation rate of the investigational drugs and poor compliance may attenuate the efficacy of actual treatment interventions. Fourth, a relatively short follow-up period may result in the lower incidence of the clinical events. Fifth, the use of 2D LVEF and the interobserver variation might affect the accuracy LVEF measurement. However, we have attempted to minimize this issue by the measurement of two independent cardiologists.