Changes in the water-electrolyte balance and myocardial structure induced by acute focal ischaemia.

In experiments carried out on 14 mongrel dogs the ischaemic and the intact myocardial areas were subjected to comprehensive biochemical and electron-microscopic examination 30 min after ligation of the anterior interventricular branch of the left coronary artery. It has been found that a 30-min occlusion of the coronary artery causes a rise in sodium content, potassium loss and a total water content increase in the ischaemic zone due to a rise in its bound fraction. Morphological changes in histohaemic barriers and in microcirculation which are most pronounced in the zone of the ischaemic lesion correspond to biochemical changes. Whereas destructive changes occur in cardiomyocytes from the ischaemic zone, some adaptive processes have been found to occur in the intact areas of the myocardium.