Effects of verapamil-potassium cardioplegic solution (CPS) OB myocardial protection were studied durig the ischemic period of aortic cross-ciatnping in patients undergoing valve replacement. 165 patients were divided into two groups.Croupl (n = 84) with cold potassium CPS

in which

Img/L of verapamil was added.Group 2 (n = 81) as control

with cold potassium CPS alone. As compared to the control group the results showed that (1) hearts were rapidly arrested in diastolic phase

electrocardiac activity was depre ssed more completeli; ( 2 ) before cardiac arret or following reperfusion the incidence of ventricular fibrillation were obviously less than control group

recovery of cardiac function after bypass was better

and incidence of serious low-output syndromewas lower; (3) electron microscopic examination demonstrated myocardial ultrastructural changes

particularly mitochondrial damages were less and milder. It is concluded that verapamil intensifies the myocardial protective effect of cold CPS