Abstract
Six mongrel dogs were used for this study. Intraaortic balloon pump(IABP) was inserted through the femoral artery and positioned in the descending thoracic aorta. After 7-paired ultrasonic sonomicrometers(USM) were embedded inside the left ventricular wall, the left anterior descending coronary artery(LAD) was ligated. 3-paired USM5 were used for obtaining the left ventricular volume(LVV), and another 4-paired USMs were for the regional muscle areas(Am).The bulk mechanical work(BMW; mW/100gLVW), regional mechanical work in the ischemic area(RMWi; mw/cm3) and in the normal area(RMWn) were calculated from LVV and Am, respectively. Effects of IABP on cardiac mechanics were compared with those of left ventricular assist device(LVAD). Results obtained were: (1) During IABP, BMWs were reduced by 7% from IABP-off results. (2) RMWi decreased by 35 to 52% by IABP, and RMWn increased by 10 to 23%. On the other hand, LVAD reduced RMWi and RMWn by 55 to 150%.
