Experimental study of cardial protection with retrograde coronary sinus perfusion in beating heart

Objective To study the myocardial protective effects of retrograde coronary sinus perfusion in beating heart. Methods Isolated rabbit working heart models were used in this study. Thirty two isolated rabbit hearts were randomized to four groups, group A received antegrade perfusion with KH, group B were maintained heart beating by retrograde perfusion with normothermic oxygenated blood, group C received retrograde coronary sinus perfusion with warm blood cardioplegia, group D with cold blood cardioplegia. After retrograde perfusion for 60 min, the hearts were switched on Langendorff Neely antegrade perfused working heart model for another 60 min. The cardiac function, myocardial enzyme leak, myocardial content of lactate, intramyocyte free calcium, ATPase of myocardial membrane and MDA of myocardial membrane were measured. Results ① After retrograde coronary sinus perfusion, recovery of cardiac funtion, activity of ATPase of the myocardial membrane in group B was superior to those of group C and D. Recovery of group C was better than group D. ② The leak of CK, LDH, myocardial content of lactate and MDA, and the intramyocyte calcium after retrograde perfusion was much lower in group B than those of group C and D. Conclusion Myocarial protective effects of retrograde normothermic oxygenated blood perfused beating heart is superior to those perfused with cold blood cardioplegia or warm blood cardioplegia.