Cumulative incidence of severe ventricular arrhythmia according to total lifetime exercise dose below or above 9.6 MET h/week. Panel A shows the cumulative incidence plot displaying higher age-related incidence of severe ventricular arrhythmia in MVP patients with exercise dose above 9.6 MET h/week compared to those with exercise dose below 9.6 MET h/week. Panel B shows the univariate and multivariate logistic regression models for the association between severe VA, exercise dose above 9.6 MET h/week, and age. CI, confidence interval; MET, metabolic equivalents of task; OR, odds ratio; VA, ventricular arrhythmia.