A new application of the ST-HR loop to evaluate the exercise-induced reversible ischemia in healed anterior wall myocardial infarction.
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.
Taniai
Seiichi
S
Second Department of Internal Medicine, Kyorin University School of Medicine, Tokyo, Japan.
Koide
Yasushi
Y
Yotsukura
Masayuki
M
Nishimura
Tohru
T
Kachi
Eisei
E
Sakata
Konomi
K
Yoshino
Hideaki
H
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