Protection of the heart by Nifedipine cardioplegia during coronary artery surgery. A clinical-haemodynamic evaluation

This study was undertaken to evaluate the myocardial preservationobtained by adding a Ca++ channel blocker, nifedipine, to cold potassiumcardioplegia (4 mcg/Kg/L) in 24 patients undergoing coronary arterysurgery. They were randomly divided into a treated (N) and a control (C)group. Significant differences between the two groups were noted in thecardiac arrest time (p less than 0.001), in the mechanical recovery mode (pless than 0.01) and in the inotropic support needed (p less than 0.01).Cardiac index increased significantly in group N but decreased in group C(p less than 0.01). Peripheral delta P/delta t and endocardial viabilityratio (EVR) decreased in both groups. Coronary sinus and serum CK and CK-MBrelease were significantly lower in the treated group. ECG ischaemicchanges occurred in 8 patients in group C but only in 1 case in group N (pless than 0.001). Arrhythmias occurred in 3 cases in group C (p less than0.05). The incidence of perioperative myocardial infarction was notsignificant (2 cases in group C). These data suggest that nifedipine canprotect the myocardial cell from ischaemic injury without depressingmyocardial contractility or AV conduction.