抄録
INO-OKA, E., KITAOKA, S., SHIMIZU, Y., KYONO, H., MAEHARA, K., MARUYAMA, Y., ASHIKAWA, K., ISOYAMA, S., TAMAKI, K., SATOH, S., SUZUKI, H., ISHIDE, N. and TAKISHIMA, T. The Effect of Heart Rate and Left Ventricular End-Diastolic Pressure on the Direction of ST Segment Displacement in Acute Ischemia. Tohoku J. exp. Med., 1984, 144 (1), 43-55 - The correlation between the ST segment displacement and coronary blood flow in various hemodynamic conditions was studied. Five isolated, isovolumic contracting canine hearts were used. The left main and the right and left circumflex (LCx) coronary arteries were cannulated and perfused with support dog's arterial blood. Four pairs of Ag-AgCl ECG electrodes were attached to the epicardium and subendocardium in the LCx perfused area. Heart rate and left ventricular end-diastolic pressure (LVEDP) were controlled by means of right atrial electrical pacing and infusion or withdrawal of arterial blood into the left ventricle, respectively. LCx flow was reduced by 75, 50, 25% of the control level under the condition of 200beats/min of heart rate and 20mmHg or 5mmHg of LVEDP, and ECGs were recorded. The ST segment elevation was observed in epi- and subendocardial lead ECGs when LCx flow was reduced from 110±27.5ml/min/100g to 72±3ml/min/100g under the condition of normal LVEDP (5mmHg) and a high heart rate (200beats/min), whereas the same degree of reduction in LCx flow under the condition of high LVEDP (20mmHg) and high heart rate (200beats/min) resulted in an epicardial ST segment depression associated with marked subendocardial ST segment elevation. The results suggest that the coronary flow reduction with a higher LVEDP will induce subendocardial ischemia, whereas the same degree flow reduction with a nomal LVEDP induce transmural ischemia.
