Myocardial cell electrolytes and water during acute ischemia.

This study was intended to define the early early electrolyte and water abnormalities of ischemic myocardium in the intact anesthetized dog. We have defined the appropriate circumstances for using 52Cr-ethyelendiamineletraacetate as an extracellular marker during ischemia and have discerned no change in this space at a time when tissue water increments were observed, by 15 min of ischemia. Calculated on the basis of cell dry weight, the cell sodium increment exceeded potassium loss in this early period of ischemia. This is consistent with the view that interference with energy metabolism reduces the pumping of sodium from the cell. The enhanced entry of sodium is associated with a gain of water, initiating events that effect irreversibility.