title: Occurrence of sustained increase in QT dispersion following exercise in patients with residual myocardial ischemia after healing of anterior wall myocardial infarction.
abstract: Our objective was to evaluate the effect of exercise on QT dispersion over the next 3 hours, as seen on a standard 12-lead electrocardiogram in patients with healed myocardial infarction with or without residual ischemia. We measured QT and QTc dispersion before, immediately after, and 1 and 2 hours after symptom-limited, dynamic treadmill exercise tests in 28 patients with healed anterior wall myocardial infarction with (group I, n = 18) and without (group II, n = 10) residual ischemia. The same protocol was followed in 5 group I patients after successful performance of coronary angioplasty. QT and QTc dispersion did not change immediately after exercise in group II. These parameters increased in group I (QT dispersion at rest [mean +/- SD] 57 +/- 22 ms, and after exercise 87 +/- 27 ms; QTc dispersion at rest 62 +/- 25 ms, and after exercise 114 +/- 36 ms). The increases in QT and QTc dispersion were sustained for at least 2 hours. After a successful coronary angioplasty in 5 patients, these parameters no longer increased with exercise. Thus, QT dispersion increased for at least 2 hours after exercise in patients who had residual ischemia after healing of myocardial infarction. Data obtained in 5 of these patients after coronary angioplasty support the idea that residual ischemia plays a key role in the sustained increase in QT dispersion after exercise.
authors.affiliation: Osaka Minami National Hospital, and First Department of Medicine, Osaka University Medical School, Suita, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Naka
authors.forename: I
authors.initials: I
authors.lastname: Shiotani
authors.forename: Y
authors.initials: Y
authors.lastname: Koretsune
authors.forename: K
authors.initials: K
authors.lastname: Imai
authors.forename: Y
authors.initials: Y
authors.lastname: Akamatsu
authors.forename: E
authors.initials: E
authors.lastname: Hishida
authors.forename: N
authors.initials: N
authors.lastname: Kinoshita
authors.forename: Y
authors.initials: Y
authors.lastname: Katsube
authors.forename: H
authors.initials: H
authors.lastname: Sato
authors.forename: M
authors.initials: M
authors.lastname: Hori
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015906:Angioplasty, Balloon, Coronary; D017023:Coronary Angiography; D004562:Electrocardiography; D005080:Exercise Test; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000503:physiopathology*; D017202:Myocardial Ischemia / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000628:therapy