title: Stress-induced ST-segment elevation following myocardial infarction and its role in wall motion abnormality, myocardial ischemia and viability: comparison of response to exercise, dobutamine and dipyridamole.
abstract: Stress-induced ST-segment elevation following myocardial infarction (MI) has been correlated with myocardial ischemia, viability and wall motion abnormality, but its mechanism is still unclear, so the present study compared ST-segment elevation and wall motion response during exercise, dobutamine and dipyridamole stresses. Twenty-five patients with their first anterior MI underwent exercise, dobutamine and dipyridamole echocardiography on different days 4-6 weeks after MI. Left ventricular wall motion was analyzed using 5-grade/16-segment model and myocardial ischemia was considered as a worsening of the wall motion score index (WMSI) during the stress test; myocardial viability was defined as a reduction of WMSI during low dose dobutamine. Dyskinesis formation was defined by visual analysis as akinesis that became dyskinetic or if the dyskinesis worsened. Both exercise and dobutamine induced ST-segment elevation, but dipyridamole did not. There was no significant difference in the degree of ST-segment elevation between the patients with and without myocardial ischemia or dyskinesis formation. Exercise induced a higher ST-segment elevation in patients with myocardial viability than those without (0.17+/-0.09 mV vs 0.09+/-0.07 mV, p<0.05). Exercise-induced ST-segment elevations correlated with dobutamine-induced ST-segment elevations (p<0.01), changes in heart rate (p<0.05) and systolic blood pressure (p<0.05). In conclusions, stress-induced ST-segment elevation does not correlate with either myocardial ischemia or stress-induced dyskinesis, but may be associated with myocardial viability.
authors.affiliation: First Department of Internal Medicine, Kinki University School of Medicine, Osakasayama, Japan. tdhk@mac.com
authors.forename: T
authors.initials: T
authors.lastname: Yamamoto
authors.forename: T
authors.initials: T
authors.lastname: Miyazaki
authors.forename: Y
authors.initials: Y
authors.lastname: Hirano
authors.forename: K
authors.initials: K
authors.lastname: Ishikawa
mesh_terms: D002316:Cardiotonic Agents / Q000494:pharmacology; D002470:Cell Survival; D004176:Dipyridamole / Q000494:pharmacology; D004280:Dobutamine / Q000494:pharmacology; D004562:Electrocardiography; D015444:Exercise / Q000502:physiology; D005260:Female; D006439:Hemodynamics / Q000502:physiology; D006801:Humans; D008297:Male; D009200:Myocardial Contraction; D009203:Myocardial Infarction / Q000503:physiopathology*; D017202:Myocardial Ischemia; D009206:Myocardium / Q000166:cytology*; D013312:Stress, Physiological / Q000503:physiopathology*; D016277:Ventricular Function, Left
chemical_list: D002316:Cardiotonic Agents; D004280:Dobutamine; D004176:Dipyridamole