[A clinical study of diltiazem administration using cold glucose-insulin-potassium cardioplegic solution--comparison between diltiazem cardioplegia and diltiazem pretreatment].

A recent idea of myocardial injury during open heart surgery is thought to be caused by the intracellular calcium overload. So, one possibility for improving myocardial protection is expected on the blocking agents of transmembrane calcium movements. This study was designed to clarify the effect of Diltiazem, a kind of calcium blocking agents, on myocardial protection in terms of hemodynamics and plasma Diltiazem concentration. 38 patients who underwent coronary artery bypass grafting using glucose-insulin-potassium cardioplegic solution (GIK) were divided into three groups Control (CO) group: no Diltiazem administration. Diltiazem cardioplegia (DC) group: GIK containing 7.5 mg/l Diltiazem was used. Diltiazem pretreatment (DP) group: Diltiazem was administered intravenously 1.5 micrograms/kg/min before operation to after operation continuously. Plasma Diltiazem concentration was constantly kept at about 150 ng/ml during 24 hours after surgery in DP. On the contrary, in DC, the level was very high (10,000 ng/ml) during aortic cross clamp but decreased about 50 ng/ml at 3 hours after surgery, and Diltiazem was not detected in CO. DC included many cases of bradycardia required pacing, however, it diminished as plasma concentration decreased. Aid of catecholamin administration was reasonable in three groups. DP and DC included many cases of commendable cardiac function in terms of cardiac index, systemic vascular resistance and left ventricular work during acute stage of surgery, and there were no coronary spasm and perioperative infarction. It is concluded that Diltiazem is effective to keep good cardiac function after reperfusion, and combined (Diltiazem pretreatment--1.5 micrograms/kg/min drip infusion-and Diltiazem cardioplegia-total dose 150-300 micrograms/kg) administration should be advisable.