[Comparison of tolerance to ischemia in human and animal myocardium during various forms of induced cardiac arrest (author's transl)].

In a total of 16 patients the tissue pH was determined on myocardium both during surgery and on isolated samples. Cardiac arrest was induced by hypothermal infusion cardioplegia and external cooling. In the isolated human myocardium section pH values were continuously determined at 15 degrees C. Parallel to these measurements samples were taken for electron microscopic examinations. In this way the pH limit under which the human myocardium cannot be revived could be visualized by additional morphologic examination. These results and those from the intrasurgical measurements with a fixed heart muscle surface probe were compared with each other and with results from animal experiments.