title: Peri-infarction zone at risk during the first 5 days after an acute transmural myocardial infarction: electrocardiographic evidence.
abstract: An atrial pacing test was performed daily during the initial 5 days after a first myocardial infarction (MI) in 33 patients in Killip class I or II, to assess the presence of areas at risk of ischemia. Pacing caused a transient ST-segment shift of 1 mm or more in 26 patients (79%) (positive test, Group I) in the first 3.6 +/- 1.1 days after infarction, whereas no ST-segment change developed during pacing in 7 patients (negative test, Group II). Pacing-induced electrocardiographic changes were always localized in the leads involved by the MI. Right and left ventricular filling pressures were higher in Group I than in Group II (8 +/- 4 vs 5 +/- 3 mm Hg, p less than 0.05, and 16 +/- 7 vs 12 +/- 7 mm Hg, p less than 0.02, respectively). Both groups had similar increases in peak enzyme values and a similar mortality rate (2 of 26 vs 1 of 7 at an average follow-up of 16 months). The reinfarction rate was higher in Group II (3 of 7 vs 1 of 26). In 7 patients similar to the 33 patients studied, metabolic studies revealed lactate abnormalities during pacing in 4 of the 6 patients with positive test results and unchanged metabolism in the patient with a negative test result. Thus a jeopardized peri-infarction area appears to exist in most patients soon after an uncomplicated MI. Its presence is often associated with silent heart failure, but it is probably unrelated to peak enzyme increase or to prognosis.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D000328:Adult; D000368:Aged; D002304:Cardiac Pacing, Artificial; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006339:Heart Rate; D006801:Humans; D007773:Lactates / Q000097:blood; D019344:Lactic Acid; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000401:mortality / Q000473:pathology; D009206:Myocardium / Q000378:metabolism; D010101:Oxygen Consumption; D012008:Recurrence; D012306:Risk; D013997:Time Factors
chemical_list: D007773:Lactates; D019344:Lactic Acid