Vevo 770 imaging system

Cross-sectional, two-dimensional and Doppler transthoracic echocardiography was performed by experienced sonographers using a Vevo770 Imaging System (VisualSonics Inc, Toronto, ON, Canada). The chests of the male mice were shaved and treated with a chemical hair remover to reduce ultrasound attenuation. Heart rate and core temperature were continuously monitored. Mice were anesthetized with 1–2% isofluorane. Images were stored in the Visual Sonics Imaging System for offline analysis. The values of heart ejection fraction (EF %), fractional shortening (FS %), end-diastolic (LV vol; d) and end-systolic (LV vol; s) of left ventricular were the average of six mice of each genotype.

Before, during (week 5 of the study), and at the end of the study (week 8 of the study), cardiac function was evaluated in anesthetized rats using non-invasive transthoracic M-Mode echocardiography (Visual SONICS VeVo 770 imaging system with a RMV710B; Toronto, Ontario, Canada). Rats were anesthetized for about 30–45 min with an intramuscular injection of ketamine hydrochloride (100 mg/kg) and medetomidine (0.25 mg/kg). At 5 weeks, atipamezole was used as anesthetic reversal in the same medetomidine volume. Transthoracic echocardiographic determinations (LVEF%; LVFS% and HR bpm) were performed in the lateral decubitus position as previously reported (Rinaldi et al., 2013 (link)). A 3-min ECG (speed 50 mm/s) was recorded at 5 and 8 week time points. After the completion of all the training and echocardiographic procedures the rats, still under anesthesia, had the chest rapidly and carefully opened longitudinally at the level of the sternum, avoiding the mammary artery. The hearts were then excised and posed on dry ice.

Transthoracic echocardiography was performed 4 weeks after LAD ligation using a Vevo770 imaging system (VisualSonics, Inc.). The following parameters were quantified by digitally recorded two-dimensional short-axis M-mode tracings at the papillary muscle level: LVESD, LVEDD, LVESV, LVEDV, LVEF, and LVFS.

Mice were anesthetized with a cocktail of ketamine, xylazine, and atropine (100 mg/kg, 10 mg/kg, and 1.2 mg/kg, respectively, i.p.) for echocardiography. Both two-dimensional M-mode and three-dimensional Doppler echocardiography were performed by using the Vevo 770 imaging system (VisualSonics, Toronto, Canada) to evaluate cardiac diameter and function. Derived echocardiography parameters included LV ejection fraction (LVEF) and LV fractional shortening (LVFS). The ratio of early to late mitral inflow velocity (E/A) and E velocity deceleration time were used to assess LV filling, which were obtained by the apical four-chamber view at the level of mitral inflow.

Ligation of the left anterior descending coronary artery of adult male Wistar rats (CAL) results in heart failure ~ 16 weeks after surgery, with left ventricular hypertrophy and dilatation, and systolic and diastolic dysfunction [15] (link). Operations were performed under surgical anesthesia (ketamine 75 mg/kg, medetomidine 0.5 mg/kg, ip) with appropriate analgesia (buprenorphine 0.05 mg/kg, sc). The corresponding sham operation (Sham) was identical except that no tie was placed around the coronary artery. All procedures were performed in accordance with UK legislation and were approved by the University of Bristol Ethics Committee. Echocardiography was used to measure cardiac function in vivo, under isoflurane (1.5%) anesthesia using the Vevo 770 imaging system (Visualsonics Inc.) with an 11–24 MHz scanhead (RMV716). Images were taken in the long axis view and ejection fraction and left ventricular systolic and diastolic volumes calculated from 2 to 3 cardiac cycles.