Boxplot of left ventricular ejection fraction (A), global longitudinal strain (B), left ventricular mass index (C), left ventricular end-systolic volume index (D), and left ventricular end-diastolic index (E) in participants with increasing number of abnormal global electrical heterogeneity parameters. Median (white horizontal line crossing the box) and interquartile range (IQR) (box) of each echocardiographic parameter are shown. Whiskers specify the adjacent values, defined as the most extreme values within 1.5 IQR of the nearer quartile.