Key result
Exercise ST elevation in Q-wave leads is linked to severe LV wall motion abnormalities in ~85%.
Why the study?
Controversy exists regarding the significance of postexercise ST-segment elevation in infarct-related leads in patients with previous myocardial infarction.
Observational (n=36)
Effect estimate: kappa coefficient 0.39
p-value: p=<0.01
May indicate severe LV dysfunction over ischemia post-MI; hypothesis-generating and should not yet change practice.
In patients with a previous myocardial infarction, controversy exists regarding the significance of postexercise ST-segment elevation in the infarct-related leads. Although usually admitted to be a sign of left ventricular dysfunction or myocardial aneurysm, other studies however have related this finding to transient myocardial ischemia and to the presence of jeopardized but viable myocardium in the infarct area. The aim of the present study was to assess the significance of postexercise ST-segment elevation in Q-wave leads as a marker of transmural ischemia or left ventricular dysfunction in 36 consecutive patients, 16 with exercise-induced ST-segment elevation in infarct-related leads. Patients were evaluated by treadmill exercise testing, coronary angiography and ventriculography, thallium-201 tomographic scintigraphy and radionuclide ventriculography within 3 months of the first myocardial infarction. Sixteen patients (group I) had exercise-induced ST segment elevation and 20 (group II) postexercise inversion, no change or pseudonormalization of the T wave in infarct-related leads. The study showed no difference in infarct-related artery, vessel disease or luminal diameter stenosis in groups I and II. The overall agreement between ST shifts and myocardial perfusion in the infarct area was 30.56% with a kappa coefficient of -0.33 (p = NS). The overall agreement between ST shifts and wall motion abnormalities was 69.44% with a kappa coefficient of 0.39 (p < 0.01), stress-induced ST-segment elevation being associated with severe wall contractile disorders in 85% of the patients. In conclusion stress-induced ST-segment elevation in Q wave leads, although not a marker of wall motion abnormalities, is associated with akinesia or dyskinesia of the left ventricular wall.
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Macieira-Coelho et al. (1999) conducted an observational in Previous Q-wave myocardial infarction (n=36). Exercise-induced ST-segment elevation in infarct-related leads vs. Postexercise inversion, no change or pseudonormalization of the T wave was evaluated on Agreement between ST shifts and wall motion abnormalities (kappa coefficient 0.39, p=<0.01). Exercise-induced ST-segment elevation in Q wave leads was significantly associated with severe left ventricular wall contractile disorders in 85% of patients (kappa coefficient 0.39, p<0.01).
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