Associations of heart rate (HR), body weight, and age with echocardiographic variables in Asian elephants (Elephas maximus) included in the study. HR are expressed in beats per minute, body weight in kilograms, and age in years.

Echocardiographic dimensions are in millimeters (mm), and indices in percent (%). Regression estimates are expressed per unit increase in the corresponding predictor. Multivariable linear mixed-effects models were fitted for each echocardiographic parameter with HR, body weight, and age as fixed effects and individual animal as a random effect. The table reports the estimated effect size (Estimate), the 95% confidence interval (CI), and the corresponding P-value for each predictor. Significant associations (P IVSd and IVSs: interventricular septal thickness at end-diastole and end-systole, respectively. LVFWd and LVFWs: left ventricular free wall thickness at end-diastole and end-systole, respectively. LVIDd and LVIDs: left ventricular internal diameter at end-diastole and end-systole, respectively. FS%: fractional shortening. LV FAC%: left ventricular fractional area change.