POTASSIUM-INDUCED CARDIOPLEGIA DURING NORMOTHERMIC CARDIAC-ARREST - MORPHOLOGIC STUDY OF THE EFFECT OF VARYING CONCENTRATIONS OF POTASSIUM ON MYOCARDIAL ANOXIC INJURY

  • 1 January 1979
    • journal article
    • research article
    • Vol. 77  (4) , 602-607
Abstract
Most corrective procedures and myocardial revascularization require a period of cardiac arrest. Numerous methods were proposed to protect the myocardium during the ischemic episode; K-induced cardioplegia is apparently a beneficial method. Myocardial necrosis may result at very high doses of K, so the effect of varying concentrations of K on myocardial anoxic injury was studied. Using an isolated rat heart preparation, anoxic injury occurring with cardioplegic solutions containing various concentrations of K+, ranging from 15-200 meq/l, during a 50 min normothermic arrest followed by 60 min of reperfusion was evaluated. Transverse histologic sections of the left ventricular myocardium were analyzed for contraction band injury by morphometric and qualitative methods. In 62 animals studied the least severe anoxic injury was seen with K+ cardioplegia at concentrations of 25 and 30 meq/l. At lower and higher concentrations there was little difference between the hearts exposed to anoxia with or without K+ cardioplegia. K administered in very high doses, i.e., 100 or 200 meq/l, led to contracture and extensive myocardial cell injury. Apparently K-induced cardioplegia is effective in reducing cell injury due to anoxia and an optimal concentration range was 25-30 meq/l.