The limit of application of intraaortic balloon pumping (IABP) on canine myocardial infarction.

The limit of application of intraaortic balloon pumping was evaluated in cases of canine myocardial infarction produced by either ligation of the descending coronary artery and of branches in the right coronary artery or establishment of stenosis in the left main coronary artery. The limit of application of intraaortic balloon pumping was confirmed to be as follows: 1) stenosis of seventy-five per cent or more in left main coronary artery, 2) over 45 per cent infarction of the entire left ventricular free wall, 3) endocardial viability ratio of less than 0.65, 4) blood flow of less than 18 ml/min/100 g in the left circumflex coronary artery when the left descending coronary artery was ligated, 5) and less than 0.69 in the ratio of inside blood flow to outside of the left ventricular free wall, as related to regional myocardial blood flow.