Verapamil and myocardial preservation in patients undergoing coronary artery bypass surgery

The value of verapamil hydrochloride as a myocardial preservative when administered prior to or during periods of myocardial ischemia was studied in patients with normal preoperative cardiac function during elective coronary artery bypass grafting. Myocardial protection included systemic hypothermia (28 degrees C) and hypothermic hyperkalemic cardioplegia. Patients were randomly divided into four groups. Group 1 received intravenous administration of verapamil prior to aortic cross-clamping. Group 2 received intravenous verapamil plus verapamil in the cardioplegic solution. Group 3 received verapamil in the cardioplegic solution only. Group 4 was given no verapamil. Oxygen extraction during the reperfusion period was greatest in Group 4. However, the incidence of pacing was 50 to 78% in Groups 2 and 3, who were given verapamil in the cardioplegic solution. These groups also had a greater need for inotropic agents for discontinuation of cardiopulmonary bypass (CPB). This study indicates that verapamil may be a useful pretreatment prior to CPB and ischemia, but is not effective and may even be detrimental when administered during ischemic periods to patients with good myocardial function.