Abstract
We performed a prospective, randomized clinical study on 211 elective coronary artery
bypass patients to assess the antiischemic and antiarrhythmic effects of the calcium
channel blocker diltiazem. Patients received perioperatively continuous 24-hour infusions
of either diltiazem (0.1 mg/kg/hour; n = 104) or nitroglycerin (1 μg/kg/minute; n
= 107). Patients randomized to the diltiazem group were kept on continuous oral diltiazem
medication postoperatively (3×50 mg/day). After a postoperative follow-up period of
2 years, 119 of the 211 patients were available for a clinical evaluation: 56 patients
randomized to the diltiazem group and 63 patients randomized to the control group.
Twenty patients from the diltiazem and 14 control patients did not follow their medicamentation
and were excluded from further study. The two groups did not differ with respect to
preoperative and surgical data. Postoperatively, the incidence of atrial fibrillation
(4.8% vs 18.6%, p < 0.05) and the frequency of ventricular premature couplets (VPC)/hour (22 ± 6 vs
37 ± 11, p < 0.05), Lown II arrhythmias (VPC >30/hour) (99 ± 19 vs 254 ± 58, p < 0.05), and ventricular runs/hour (7 ± 15 vs 38 ± 25, p < 0.05) were significantly lower in the diltiazem group. Furthermore, patients of
the diltiazem group had significantly lower peak values of ischemia-sensitive laboratory
parameters: creatine kinase-MB (17.6 ± 14.3 vs 25.3 ± 16.3 U/L, p < 0.05), CK-MB-mass concentration (35.2 ± 38.4 vs 51.5 ± 33.9 μg/L, p < 0.05), and troponin-T (0.98 ± 0.7 vs 1.7 ± 0.8 μg/L, p < 0.05). Two years after coronary artery bypass surgery, fewer patients randomized
to the diltiazem group showed signs of cardiac failure (0 vs 6.1%), ST-segment alterations
during exercise (5.5% vs 13.2%, p < 0.05), symptoms of angina during exercise (18.5% vs 22.4%, n.s.), atrial fibrillation
(0 vs 2.0%), and new left bundle branch block (0 vs 8.2%), compared with controls.
It is concluded that the calcium antagonist diltiazem is effective in reducing incidence
and extent of arrhythmias and myocardial ischemia perioperatively and provides potent
postoperative antiischemic and antiarrhythmic protection in patients after coronary
artery bypass surgery.
