Electrophysiologic effects of quinaprilat in dogs during acute myocardial ischemia and following reperfusion.
BACKGROUND
There have been few studies concerning the electrophysiologic changes associated with the use of angiotensin-converting enzyme inhibitors in patients with acute myocardial infarction. We examined the electrophysiologic effects of quinaprilat in dogs during acute myocardial ischemia and following reperfusion.


METHODS
The left anterior descending coronary artery was occluded for 10 min and reperfused for 10 min. Animals received intravenous quinaprilat (3 micrograms/kg per min, quinaprilat group) or saline (control group). We measured the ventricular effective refractory period and intra-myocardial conduction time within the left anterior descending coronary artery region (ischemic region) during myocardial ischemia and following reperfusion, and determined the frequency of ventricular fibrillation.


RESULTS
The effective refractory period in the ischemic region decreased during myocardial ischemia and decreased further immediately after reperfusion in the control group. The intra-myocardial conduction time in the ischemic region increased during myocardial ischemia but rapidly shortened after reperfusion in the control group. In the quinaprilat group, however, no significant differences were evident between the ischemic and non-ischemic regions in either the effective refractory period or the intra-myocardial conduction time during myocardial ischemia or following reperfusion. The percentage shortening of the effective refractory period and the percentage prolongation of the intra-myocardial conduction time in the ischemic region were significantly lower in the quinaprilat group than in the control group during myocardial ischemia and following reperfusion. The frequency of ventricular fibrillation during myocardial ischemia and following reperfusion was significantly lower in the quinaprilat group (21%) than in the control group (74%; P < 0.01).


CONCLUSIONS
Quinaprilat protects against electrophysiologic abnormalities, and may decrease arrhythmias during acute myocardial ischemia and following reperfusion.
Fujinaga
H
H
Second Department of Internal Medicine, School of Medicine, University of Tokushima, Japan.
Wakatsuki
T
T
Nishikado
A
A
Oki
T
T
Ito
S
S
D000208:Acute Disease; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000008:administration & dosage*; D000818:Animals; D004195:Disease Models, Animal; D004285:Dogs; D004562:Electrocardiography / Q000187:drug effects*; D006329:Heart Conduction System / Q000187:drug effects / Q000503:physiopathology; D006339:Heart Rate / Q000187:drug effects; D007275:Injections, Intravenous; D007546:Isoquinolines / Q000008:administration & dosage*; D017202:Myocardial Ischemia / Q000188:drug therapy / Q000209:etiology / Q000503:physiopathology*; D015425:Myocardial Reperfusion / Q000009:adverse effects; D044005:Tetrahydroisoquinolines; D014693:Ventricular Fibrillation / Q000188:drug therapy / Q000209:etiology / Q000503:physiopathology
D000806:Angiotensin-Converting Enzyme Inhibitors; D007546:Isoquinolines; D044005:Tetrahydroisoquinolines; C054501:quinaprilat