Echocardiography and electrocardiogram.

Mice were anesthetized with Avertin (0.25 mg/g body wt) and weighed to determine body mass. Echocardiography was performed using VisualSonics Vevo 770 (VisualSonics, Toronto, Ontario, CA). Results from two-dimensional M-mode analysis along the short axis (at the level of the largest LV diameter) were used to determine LV mass, LV end diastolic dimension (LVEDD), wall thickness, ejection fraction, and LV fractional shortening. LV mass values were normalized to mouse body weight. Upon completion of echocardiography, mice were terminated by cervical dislocation under Avertin anesthesia and wet heart weight was measured.