title: A new application of the ST-HR loop to evaluate the exercise-induced reversible ischemia in healed anterior wall myocardial infarction.
abstract: Exercise-induced ST-segment elevation in infarct-related leads is often seen on the treadmill exercise electrocardiogram of patients with anterior wall myocardial infarction. However, the cause of this phenomenon is still a matter of controversy. The purpose of this study was to evaluate the relation between the direction of ST-segment-heart rate (ST-HR) loop rotation and reversible myocardial ischemia in the infarct-related area. A total of 58 patients were enrolled in this study. They had healed anterior wall myocardial infarctions with single-vessel coronary artery disease and exercise-induced ST-segment elevations in the infarct-related leads, as observed on treadmill exercise electrocardiograms. All patients underwent treadmill exercise electrocardiography and dobutamine stress echocardiography at discharge. The direction of rotation of the ST-HR loop constructed from the treadmill exercise electrocardiogram and the dobutamine stress echocardiographic findings in the infarct-related area were compared. Counterclockwise rotation was seen in 26 of 58 patients. Compared with clockwise rotation, patients with counterclockwise rotation had significantly more viable myocardium (92% vs 69%, p = 0.04) and presence of reversible myocardial ischemia (58% vs 6%, p < 0.01). On the basis of the counterclockwise rotation findings, the diagnostic value of the presence of reversible myocardial ischemia was calculated. The sensitivity, specificity, and accuracy was 88%, 73%, and 77%, respectively. Counterclockwise rotation of ST-HR loops was strongly related to reversible myocardial ischemia in the infarct-related area. In conclusion, our results have shown that analysis of ST-HR loops may be useful in evaluating the cause of exercise-induced ST-segment elevation in infarct-related leads.
authors.affiliation: Second Department of Internal Medicine, Kyorin University School of Medicine, Tokyo, Japan.
authors.forename: Seiichi
authors.initials: S
authors.lastname: Taniai
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Koide
authors.forename: Masayuki
authors.initials: M
authors.lastname: Yotsukura
authors.forename: Tohru
authors.initials: T
authors.lastname: Nishimura
authors.forename: Eisei
authors.initials: E
authors.lastname: Kachi
authors.forename: Konomi
authors.initials: K
authors.lastname: Sakata
authors.forename: Hideaki
authors.initials: H
authors.lastname: Yoshino
mesh_terms: D000368:Aged; D017023:Coronary Angiography; D003327:Coronary Disease / Q000175:diagnosis* / Q000503:physiopathology; D018450:Disease Progression; D025401:Echocardiography, Stress; D004562:Electrocardiography; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000503:physiopathology*; D011379:Prognosis; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index