Reperfusion effects on the magnesium-procaine arrested rabbit heart

Rabbit hearts were subjected to cardiac arrest induced by injecting 3 isotonic cardioplegic solutions each of which contained in combination with procaine-HCl one of 3 different magnesium compounds. A period of 40 min arrest was followed by reperfusion of 15 min. A regular sinus rhythm returned after washout of the cardioplegic solution. The pattern of the essentially unaltered myocardial ultrastructure correlated with the well-preserved high-energy phosphate stores. The effects of magnesium and procaine on cell permeability and the consequences of the different fusion are discussed. The study stresses the importance of an adequate period of postischemic reperfusion of the heart in an unloaded state in support of myocardial recovery. The studies presented herein suggest further investigations of various concentrations of magnesium and procaine combined with different amounts of calcium in perfusates for the preservation of the heart and possibly of other organs.