'Early' ischemia and reperfusion-induced arrhythmias: antiarrhythmic effects of diltiazem in the conscious rat.

Abstract

The ability of diltiazem to prevent early ischemia and reperfusion-induced arrhythmias was investigated in conscious rats with coronary artery occlusion. During a 30-min period of occlusion of the left coronary artery, 100% of placebo-treated animals exhibited ventricular tachycardia, 65% exhibited ventricular fibrillation and the mean total number of premature ventricular complexes was 1076 +/- 254. Diltiazem (0.5 or 2.0 mg/kg body weight, given intravenously 10 mins prior to coronary occlusion), reduced the incidence of ventricular tachycardia to 62% (P less than 0.01) and 54% (P less than 0.001), respectively and the incidence of ventricular fibrillation to 31% (P = NS) and 15% (P less than 0.01), respectively. The total number of premature ventricular complexes was also reduced to 248 +/- 78 (P = NS) and 156 +/- 55 (P less than 0.02). The development of ST segment elevation, induced by coronary artery occlusion, was delayed in both drug-treated groups. Similarly, diltiazem, at the same doses, reduced the incidence of ventricular fibrillation induced by reperfusion after 5 mins of coronary artery occlusion from 100% to 50% (P less than 0.01) and 25% (P less than 0.001) and mortality from 87% to 42% (P less than 0.02) and 25% (P less than 0.01), respectively. The anti-arrhythmic effects of diltiazem were not related to changes in heart rate and all groups showed similar occluded zone sizes, as measured by a fluorescent microsphere technique. Thus, diltiazem affords substantial protection against both early ischemia-induced ventricular arrhythmias and reperfusion-induced arrhythmias and this action may be associated with the beneficial effects on ischemia-induced ST segment elevation.

• Authors: K Kinoshita, D J Hearse, M V Braimbridge, A S Manning
• Journal: The Canadian journal of cardiology (Can J Cardiol) 1988 Jan-Feb Vol. 4 Issue 1 Pg. 37-43 ISSN: 0828-282X [Print] England
• PMID: 3359353 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Diltiazem

Topics

• Animals
• Arrhythmias, Cardiac (physiopathology)
• Coronary Circulation (drug effects)
• Coronary Disease (physiopathology)
• Diltiazem (pharmacology)
• Dose-Response Relationship, Drug
• Electrocardiography
• Heart Conduction System (drug effects, physiopathology)
• Heart Rate (drug effects)
• Male
• Rats
• Rats, Inbred Strains
• Ventricular Fibrillation (physiopathology)