Kazuhiko Umetsu

Effects of Catecholamine and Amrinone on the Metabolism of Noninfarcted Myocardium in Cardiogenic Shock

We investigated the effects of catecholamine and amrinone (AMR) on the metabolism of noninfarcted myocardium (NIM) during heart failure in acute myocardial infarction. Acute myocardial ischemia was induced by left circumflex coronary artery ligation on dogs divided into two groups: in the C group, left ventricular pressive (LVP) remained at >70% and in the S group, LVP decreased to <70% of preligation values. In part of the S group, 10 μg/kg/min of dopamine (DOA) or dobutamine (DOB), or 60μg/kg/min of AMR, were given intravenously beginning 90 min after ligation. At the end of 120 min of ischemia, mitochondria were extracted from NIM, and respiratory and electron transport system enzyme activities were measured. In the DOA and DOB groups, LVP, myocardial blood flow, cardiac output, and max LV dp/dt recovered significantly. In the AMR group, in spite of LVP reduction, other hemodynamic parameters increased. In the S group, state III respiration, complex I, and DNP-ATPase activities in NIM decreased to 62%, 65%, and 68% of preligaton levels, respectively. These values improved markedly with DOA, DOB, and AMR treatments. Electron microscopy showed swelling and fusion of mitochondria in the S group. These results indicate that catecholamine and AMR improve energy production in NIM and ultimately improve cardiac function.

Metabolic Changes in Nonischemic Myocardium During Pump Failure

Metabolic changes in the nonischemic myocardium after acute myocardial infarction in canine hearts were studied. Ca2+-ATPase activity and the major ATPase protein of the sarcoplasmic reticulum, tissue levels of ATP, mitochondrial respiratory, and complex I activities were decreased in the noninfarcted zone in proportion to heart function. It is suggested that recovery of these functions may be important in any treatment of pump failure.