| Abstract: | Recent controversy concerns the proper vehicle for delivery of potassium cardioplegia. In the present study, adult dogs supported by cardiopulmonary bypass were subjected to 2 hours of multidose, hypothermic potassium cardioplegic arrest with 30 minutes of reperfusion with either autologous blood or crystalloid solution as the cardioplegic vehicle. Preservation of myocardial high-energy nucleotide stores was assessed by serial left ventricular biopsies assayed for adenosine triphosphate (ATP) and creatine phosphate. Preischemic and postischemic ventricular function was assessed by the use of an isovolumic intraventricular balloon. ATP stores were equally maintained at preischemic levels after ischemia and reperfusion by both autologous blood and crystalloid solution. Although creatine phosphate stores significantly declined (P less than 0.01, both groups) after 2 hours of arrest, reperfusion allowed equal restoration of preischemic levels. Maximum first derivative of left ventricular pressure and measured velocity were not depressed by either mode of protection. Similarly, myocardial compliance, as assessed by length-tension curves, showed no change following either autologous blood or crystalloid solution. The data show equal and significant myocardial protection by multidose, hypothermic potassium cardioplegia when both delivery vehicles were used. |
