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The influence of glucose-insulin-potassium infusion in combination with a mechanical assist device (intraaortic balloon pumping, IABP) on the levels of high energy phosphates in the canine heart after coronary artery ligation was compared with the effect of a separate application of these measures to protect the acute ischaemic myocardium. The combined method normalized the tissue content of creatine phosphate in the nonischaemic tissue contrary to the application of the mechanical or pharmacological assistance alone. In the ischaemic cardiac tissue only the combination of both methods reduced the loss of creatine phosphate, ATP and the sum of adenine nucleotides. With the balloon pumping a reduction in lactate accumulation was achieved, which, however, was significantly lower than that obtained by the combination of heart protective measures: IABP plus glucose-insulin-potassium.

The influence of prostacyclin (PGI2) alone or in combination with intraaortic balloon pumping (IABP) on the levels of energy-rich phosphate compounds was investigated before and after coronary artery ligation in canine myocardium. There was a higher level in creatine phosphate in the ischemic as well as non-ischemic areas of the myocardium after treatment with PGI2, however the most protective effect was registered after a combination of PGI2 and IABP. PGI2 also reduces the release of cathepsin D activity into the blood independently whether or not a mechanical support of the heart after coronary artery ligation was performed.

The influence of verapamil (V) and of V combined with glucose-insulin-potassium (VG) on ischemic injured myocardium was investigated in dogs after ligation of the left anterior descending coronary artery. Three hours after coronary artery ligation with VG application during the last two hours the left ventricular end diastolic pressure (LVEDP) and the pressure rate product were decreased in contrast to the behaviour after V infusion. Contents of ATP and creatine phosphate were preserved in equal extent by V and VG, but the lowest content in inorganic phosphate was found in ischemic and nonischemic left ventricular tissue after VG application. Thus, VG seems to enable the tissue to save more effective energy rich phosphates and to contribute to the economization of cardiac work by reduction of preload.

The influence of PGE1, iloprost and a combination of both on high energy phosphate levels in isolated rat hearts reperfused 1 h following 20 min of global ischemia was investigated employing 31P-NMR-spectroscopy. Whereas PGE1 induced a slight reduction in the decline of the creatine phosphate/inorganic phosphate. ATP/inorganic phosphate ratio and NMR-energetic index during ischemia, iloprost application was followed predominantly by a temporary but marked improvement of the creatine phosphate/inorganic phosphate ratio during the early period of reperfusion. The best results in preservation of high energy phosphates were achieved after simultaneous application of PGE1 and iloprost. It is presumed that the accelerated normalization of the heart function observed immediately after ischemia in the eicosanoid treated hearts is related to the more rapid recovery of intracardial high energy phosphate level.

The effect of drugs on eicosanoid production and on the development of atherogenic index was investigated in canine myocardial ischemia. Iloprost, verapamil, the trapidil derivative AR 12463 or 0.9% NaCl solution were administered 60 min after coronary artery ligation in anaesthetized dogs. Both iloprost and AR 12463 reduced the thromboxane A2/prostacyclin (TXA2/PGI2) ratio in coronary sinus plasma in comparison to controls. The atherogenic index was significantly decreased in the iloprost as well as in the AR 12463-treated group in comparison to the control group. Verapamil had no influence on the investigated parameters.