Diltiazem pretreatment reduces experimental myocardial infarct size in rat

Diltiazem (DZ) is a calcium channel blocking drug which has been shown to be a potent coronary artery dilating agent in the rat. Since this agent has been shown to reduce heart rate and contractility as well as to inhibit calcium transport in the ischemic myocardium, the present study was conducted to determine if DZ is effective in reducing myocardial infarct (MI) size in a rat model utilizing experimental left coronary artery ligation. Rats were pretreated (30 min presurgery) with either DZ (20 mg/kg i.p.) or saline (SA). At 48 h postsurgery, left ventricles were removed and assayed for total creatine kinase activity (CK). Percent infarct size was calculated and found to be significantly reduced from 14.8% in control SA to 6.7% of the total left ventricle in the DZ-treated group (p less than 0.01). Thus, pretreatment with DZ significantly preserves total CK activity and reduces % infarct size in the left ventricle of rats 48 h after experimental MI.