Mice were continuously anesthetized by inhalant 1.5% isoflurane/100% O2 to maintain a light sedation level. Mice were placed supine on an electrical heating pad at 37°C during the examination. The echocardiography (ECG) electrodes of the Vevo 2100 ultrasound system (Visual Sonics, Toronto, Canada) were connected to mouse paws, and heart rate and respiratory physiology were continuously monitored. Mice chests were shaved, and warmed ultrasound gel was applied to the area of interest. Transthoracic echocardiography was performed using the high-frequency linear array transducer (MS400, 18–38 MHz) of the Vevo 2100 ultrasound system. Heart was imaged in B-mode and M-mode to examine the parameters of left ventricle (LV) in diastole (-d) and systole (-s). Pulse wave Doppler imaging was performed to measure heart diastolic function. All measurements were obtained in triplicate and data were analyzed by using Vevo 2100 standard measurement software .