Diltiazem cold cardioplegia in coronary artery surgery: effects on myocardial function and ischemia.

This study was undertaken to evaluate the myocardial preservation obtained by adding a calcium channel blocker, diltiazem (200 mcg/kg of body weight) to cold potassium cardioplegia in 24 patients with coronary artery disease who underwent myocardial revascularization, and were randomly divided into a treated Group D and a Control Group C. No significant differences were noted between the groups in cardiac electrical arrest and recovery time, recovery rhythm, mechanical function recovery, inotropic support, stroke index, or cardiac index. After cardiopulmonary bypass, the stroke index decreased by 13.1% in Group D and by 20.7% in Group C; cardiac index increased in both--18.6% and 14.0%, respectively--but the results were possibly from compensatory heart rate increases. Peripheral deltaP/deltat and endocardial viability ratios decreased in both groups. Coronary sinus enzymes and serum CK were slightly lower in the treated group. Serum CK-MB, however, was significantly higher in the Control Group. Electrocardiographic ischemic changes occurred in four patients, all in Group C (p =.046). Hyperkinetic arrhythmias occurred in five of the controls, but in none of the treated patients (p =.018). One perioperative myocardial infarction was diagnosed in the Control Group. These data suggest that diltiazem has no negative side effects on hemodynamics or cardiac rhythm and does not reduce impairment of myocardial function due to ischemia, but it does decrease the incidence of ischemic lesions in patients undergoing coronary artery bypass procedures.