Determination of potassium/sodium ratio in heart tissue. Evaluation of its use as an index of myocardial ischaemic damage. Comparison with the nitro-BT test.

The succinate dehydrogenase method of staining and the determination of the K+/Na+ ratio of heart tissue have been applied to forensic material as a tool for demonstrating early signs of myocardial infarctions. Both methods are controlled by a series of forensic cases dying from causes other than arteriosclerosis of the coronary arteries. Based on an analysis of normal material some factors influencing the K+/Na+ ratio are defined. It is concluded that the determination of the K+/na+ ratio shows more infarcts than the formazan method; however, the evaluation of the K+/Na+ ratio is difficult. The K+/Na+ determination is not recommended for routine use. A possible indication for the use of the K+/Na+ determination together with the formazan test could be cases of instantaneous death by accidents suspected to have been provoked by a fatal heart attack.