[Atrioventricular conduction changes in acute ischemic and reperfused coronary artery of cats].
Acute inferior wall infarction is frequently complicated by conduction disturbance, but the relationship between ischemia and atrioventricular (AV) conduction disturbance is not well understood. The present experiments were made on cats with heart efferent completely denervated. A, H and V waves were picked up by a template-machine algorithm from His bundle electrogram, AA interval (cardiac cycle length), AH interval (AV conduction time), HV and AV intervals were measured. Of 20 cats, 14 showed prolongation of AH interval (Group A), while not in 6 cats (Group B) after ligation of right coronary artery. A fast pacing of right atrium (AA interval = 267 ms) was produced in Group B and AH interval was also prolonged after ligation of the artery. By multiple-step pacing, the curve of AV nodal function shifted to the right, AH interval which induced AV nodal block was prolonged after ischemia. After reperfusion, AH interval was shortened both in Group A and B. The above results show that myocardial ischemia may cause abnormality of AV conduction and accommodation function. The abnormality appears to be a potential danger which will induce AV conduction block during tachycardia.
Chen
S L
SL
Medical Department, 305 Hospital of PLA, Beijing 100017.
Feng
S Q
SQ
D000818:Animals; D002415:Cats; D004562:Electrocardiography; D005260:Female; D006327:Heart Block / Q000209:etiology*; D008297:Male; D009203:Myocardial Infarction / Q000150:complications*; D015428:Myocardial Reperfusion Injury / Q000150:complications*