Objective To estimate the value of aortic valves and combined mitral valve replacement with retrograde perfusion in beating hearts.Methods Continuous retrograde coronary sinus perfusion with beating hearts was used in 83 patients undergoing aortic valve or aortic valve combined with mitral valve replacement,without application of cardioplegia.After aortic valve replacement,the retrograde perfusion wes changed to antegrade perfusion for mitral valve replacement or correction of the other deformities(group A).Cold blood cardioplegia solution(15℃)was infused at intervals in 20 cases(group B).The following parameters were tested:lactate,ET,CTn-T and MDA in blood;myocardial ultra-structure;and cardiac rhythm and cardiac output (co).Results All biochemical values increased after cardiopulmonary bypass(P ＜ 0.05 - 0.01).Empty and beating heart sinus rhythm was maintained in group A.Myocardial ultrastructure did not change significantly.The pump was stopped smoothly as the surgical procedure finished.No postoperative low cardiac output syndrome or arrhythmia was observed.Eight-one patients recovered smoothly,two died from renal failure or infective shock.When the pump stopped,all patients in group B were supported by 5 - 10 μg· kg-1· min-1 dopamine.Transient pacing was used in 9 patients.One patient died from low cardiac output syndrome.Conclusion This method is a good myocardial protection which simulates physiologic status.It is applicable to aortic valve and combined mitral valve replacement of patients with large heart or heart failure and long time aortic cross-clamping.Ideal clinical effect can be achieved.