[Animal model for testing the influence of drugs on partially ischaemic and normal myocardial regions (author's transl)]. / Tiermodell zur Testing der Beeinflussung partiell ischämischer und normaler Myokardbezirke durch Pharmaka.

ABSTRACT

Blood flow was measured both in the circumflex and descending branch of the left coronary artery of anaesthetized dogs. Venous blood was sampled from the areas supplied by these vessels and arterial blood from the aorta for determination of oxygen-saturation, haemoglobin content, pCO2, glucose, lactate, and free fatty acids (FFA). The coronary blood flow in both branches, heart rate, aortic blood pressure, LVEDP and LVdp/dtmax were registered continuously. After taking control values, resting blood flow in the circumflex branch was mechanically reduced by 40% and the changes in haemodynamics and myocardial metabolism were measured 30 min thereafter. Heart rate, blood flow in the descending branch and LVEDP rose, whilst arterial blood pressure and LVdp/dt were not significantly changed. The partially ischaemic myocardium showed a decrease in lactate, FFA and oxygen uptake and CO2 release. The simultaneously determined metabolic parameters for the non-ischaemic region showed significant increases in lactate and oxygen uptake and CO2 and H-ion release. The overall balance (partially ischaemic and normal regions) showed a significant decrease in lactate and FFA uptake, which was, however, of very small magnitude. These results show that the antianginal action of drugs should not be assessed by determination of arterio-coronary venous balances for the whole heart, but for partially ischaemic and normal regions separately, as is possible in the presented experimental model. Moreover, sympathetic or direct stimulation can be used to stimulate increased effort of the heart such as occurs in angina pectoris.