The autoregulation of the heart work by the coronary perfusion pressure

Summary In 9 dog hearts (coronary arteries cannulated, aortic blood pressure allowed to change) an increase in coronary perfusion pressure raised the peak pressure in the left ventricle and the maximum ofdp/dt, while the left ventricular enddiastolic pressure decreased.An enhancement of coronary perfusion pressure in 6 dog hearts (coronary arteries cannulated, aortic blood pressure kept constant) increased the peak pressure in the left ventricle and the maximum ofdp/dt; the left ventricular enddiastolic filling pressure decreased.This coronary perfusion pressure-induced increase in heart performance can also be shown by ventricular function curves. These are relatively flat at low coronary pressures. Therefore, even large changes in left ventricular enddiastolic pressure bring about only a small increase in stroke work. Heart failure could not be observed at low coronary perfusion pressures. An increase in coronary perfusion pressure shifted the ventricular function curves to the left, so that even a small change in enddiastolic filling pressure had a great effect on strokework.The homeometric autoregulation of the heart can be explained to a certain part by the coronary perfusion pressure.There is no explanation of the effect of the coronary perfusion pressure on heart performance. Based on our findings it must be concluded that an increased coronary perfusion pressure distends the coronary arteries (garden-hose-effect), which increases myocardial fiber tension and heart performance.Supported by the Deutsche Forschungsgemeinschaft (Sonderforschungsbereich Cardiologie Düsseldorf).