抄録
This study was designed to decrease the mortality rate in the patients with cardiogenic shock following acute myocardial infarction (AMI). The effects of IABP and left heart bypass (LHB by using roller pump or artificial heart device) were compared from the standpoints of hemodynamics and myocardial metabolism (lactate extraction) in dogs with AMI produced by multiple legations of the coronary artery. Besides, in addision to AMI complete A-V block was produced by electric coagulation of the A-V node or Formalin injection into this node.
By this procedure, the infarcted area of the myocardium reached to 25-550 (average 30%) of free wall of the left ventricle. This area was clearly confirmed by postmortem coronary angiogram and NBT staining. Subsequently, the effects of diastolic augmentation and systolic unloading by IABP were clearly recognized and pacemaking was useful procedure to maintain IABP at the time of complete A-V block. Changes of hemodynamics and lactate extraction due to changing of heart rate were observed between 80 and 160/min during IABP and LHB.
These procedures were favorable methodes to improve hemodynamics and ryocardial metabolism which were remarkably disturbed by coronary ligations and complete A-V block. In this study, hemodynamics and myocardial metabolism were more greatly improved by IABP and LHB, in which the bypass flow was about 30% of the total circulating blood volume. Especially, the favorable effects could be obtained under heart rate of 120/min in the group of with application of artificial heart device.
