Electrophysiologic basis of use of a polarizing solution in the treatment of myocardial infarction

The effects of glucose, glucose and insulin, and glucose, insulin, and KCl on the action potential duration, etJective refractory period, and rate of rise of 0 phase of action potential of the human papillary muscles, obtained from patients undergoing correctice open‐heart surgery, preincubated in nonoxygenated Krebs‐Ringer solution with or without glucose, were investigated. Nonoxygenated glucose‐free solution produced a marked shortening of the action potential duration and effective refractory period and a moderate decrease in the rate of rise of 0 phase of action potential of the papillary muscles. Glucose or glucose and insulin together brought back the shortened action potential duration arui effective refractory period produced by nonoxygenated glucose‐free solutions to near controllevels while glucose and insulin with KCl was less etJective. Potassium chloride alone produced a further decrease in the action potential duration and effective refractory period and rate of rise of 0 phase of action potential. Although glucose was able only partially to restote the decrease in the rate of rise of 0 phase of action potential produced by nonoxygenated glucose‐free solution, glucose and insulin together increased the rate of rise of 0 phase of action potential to well abooe the controllevel. On the other hand, glucose, insulin, and KCl together produced a further decrease in the rate of rise of o phase of action potential in such anoxic muscles. Glucose or glucose and insulin were superior to glucose, insulin, and KCl together in reversing the effect of anoxia and substrate free solution on the transmembrane potential of papillary muscles. It is therefore suggested that glucose or glucose and insulin should be better than glucose, insulin, and KCl in the treatment of acute myocardial infarction.