Potassium cardioplegia. An alternate method of intraoperative myocardial protection.

Potassium-induced cardioplegia was studied in 38 mongrel dogs supported by normothermic cardiopulmonary bypass and subjected to 60 minutes of aortic cross clamping followed by 30 minutes of reperfusion. A study of preischemic and postischemic ventricular function and myocardial high-energy phosphate compounds, lactate, and glycogen showed substantial preservation of high-energy phosphates and ventricular performance when potassium cardioplegia was used. However, the substantial depression in contractility observed following ischemia nad reperfusion suggests that potassium cardioplegia alone does not provide adequate intraoperative protection of the myocardium.