Model of right ventricular failure after global myocardial ischemia and mechanical left ventricular support

Postcardiotomy right ventricular (RV) failure after institution of mechanical left ventricular (LV) support is poorly understood. Using a canine model supported by cardiopulmonary bypass (CPB), the animals underwent 30 min of aortic clamping or no ischemia and were weaned to an LV assist device (LVAD). Echocardiographic measurements of LV and RV cavity size off support allowed calculation of percentage change in cavity area (fractional shortening). There were no differences at baseline. After 2 hrs on LVAD, there were significant differences between ischemic and control groups in both LV (38 ± 12 vs. 61 ± 6) and RV (15 ± 3 vs. 55 ± 12). The ischemic RV also had significantly decreased function compared with the LV (38 ± 12 vs. 15 ± 3). The control group demonstrated no differences in ventricular function. The authors concluded that global ischemia diminishes LV and RV function, and this effect is accentuated in the RV after LVAD support. In controls, RV function is not affected by LVAD support, but after ischemia, LVAD support alone often will be inadequate.