Effects of diltiazem on conduction of premature impulses during acute myocardial ischemia and reperfusion.
The effect of diltiazem on conduction of cardiac impulses was studied using premature impulses. Conduction times were measured in the epicardium and endocardium in both anterograde and retrograde directions during ischemia and reperfusion of the left ventricular anterior wall. In 16 dogs (8 control and 8 treated with diltiazem), the left anterior descending artery was occluded initially below the second diagonal branch and 30 minutes later below the first diagonal branch. Infusion of diltiazem (0.02 mg/kg per min) was begun at the time of the first ligation in the treated dogs. Conduction delay in normal, ischemic  and reperfused myocardium and at the border of ischemia or reperfusion was compared in the two groups. In addition, treated and nontreated ischemic zones were analyzed in the diltiazem-treated group. Results show significantly less ischemia-induced conduction delay in the diltiazem-treated group in both ischemic myocardium and at the border of ischemia. This beneficial effect was seen in the ischemic segment in the treated dogs whether or not the medication was given before or after coronary ligation. Further, the effect of the drug on epicardial and endocardial conduction did not differ significantly. These data suggest that diltiazem may have potential value in the treatment of ventricular reentrant arrhythmias associated with acute ischemia over and above the well recognized hemodynamic and metabolic effects of calcium channel blocking agents.
D000818:Animals; D001552:Benzazepines / Q000494:pharmacology*; D003326:Coronary Circulation; D003327:Coronary Disease / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology; D003331:Coronary Vessels / Q000601:surgery; D004110:Diltiazem / Q000494:pharmacology*; D004285:Dogs; D006329:Heart Conduction System / Q000187:drug effects*; D007473:Ion Channels / Q000187:drug effects; D008026:Ligation; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects
D001552:Benzazepines; D007473:Ion Channels; D004110:Diltiazem