Combined Perioperative Infusion of Nifedipine and Metoprolol Provides Antiischemic and Antiarrhythmic Protection in Patients Undergoing Elective Aortocoronary Bypass Surgery

Abstract

A randomized study was performed on 70 patients undergoing elective coronary bypass surgery to examine whether the combined, perioperative, 24-hour infusion of the calcium-channel blocker nifedipine (10 micrograms/kg/h) and the beta 1-blocker metoprolol (12 micrograms/kg/h) reduces the incidence of perioperative myocardial ischemia and arrhythmias (group NM, n = 34). The control group received nifedipine only (n = 36). Repeated assessment of serum enzyme levels (CK, CK-MB) and 12-lead ECG, together with 3-channel Holter monitoring over 48 h were used to define perioperative myocardial ischemia (transient ischemic event, myocardial infarction) and supraventricular and ventricular arrhythmias. The two groups did not significantly differ with respect to preoperative anamnestic and surgical data. No perioperative myocardial infarction was detected in either group. However, a significantly lower incidence of transient ischemic events was observed in the NM group as compared to the nifedipine group (3% versus 11%; p < 0.05). In addition, there was a tendency towards lower CK-MB levels and peak-values of CK- and CK-MB in the NM group. With regard to perioperative dysrhythmias, there was a significantly lower incidence of sinus tachycardia (9%) and atrial flutter/fibrillation (6%) in the NM group as compared to the nifedipine group (33 and 27%, p < 0.05). In addition, postoperative heart rate was lower in the NM group starting from the 6th hour after opening of the aortic cross-clamp. In conclusion, the combined perioperative infusion of nifedipine and metoprolol is superior in preventing perioperative myocardial ischemia and decreasing the incidence of supraventricular arrhythmias as compared to a single-drug regimen with nifedipine.