The electrocardiogram predicts one-year outcome of patients with unstable angina and non-Q wave myocardial infarction: results of the TIMI III Registry ECG Ancillary Study. Thrombolysis in Myocardial Ischemia
C P Cannon, C H McCabe, P H Stone, W J Rogers, M Schactman, B W Thompson, D J Pearce, D J Diver, C Kells, T Feldman, M Williams, R S Gibson, M W Kronenberg, L I Ganz, H V Anderson, E Braunwald, C P Cannon, C H McCabe, P H Stone, W J Rogers, M Schactman, B W Thompson, D J Pearce, D J Diver, C Kells, T Feldman, M Williams, R S Gibson, M W Kronenberg, L I Ganz, H V Anderson, E Braunwald
Abstract
Objectives: We sought to determine the prognostic value of the admission electrocardiogram (ECG) in patients with unstable angina and non-Q wave myocardial infarction (MI).
Background: Although the ECG is the most widely used test for evaluating patients with unstable angina and non-Q wave MI, little prospective information is available on its value in predicting outcome in the current era of aggressive medical and interventional therapy.
Methods: ECGs with the qualifying episode of pain were analyzed in patients enrolled in the Thrombolysis in Myocardial Ischemia (TIMI) III Registry, a prospective study of patients admitted to the hospital with unstable angina or non-Q wave MI.
Results: New ST segment deviation > or = 1 mm was present in 14.3% of 1,416 enrolled patients, isolated T wave inversion in 21.9% and left bundle branch block (LBBB) in 9.0%. By 1-year follow-up, death or MI occurred in 11% of patients with > or = 1 mm ST segment deviation compared with 6.8% of patients with new, isolated T wave inversion and 8.2% of those with no ECG changes (p < 0.001 when comparing ST with no ST segment deviation). Two other high risk groups were identified: those with only 0.5-mm ST segment deviation and those with LBBB, whose rates of death or MI by 1 year were 16.3% and 22.9%, respectively. On multivariate analysis, ST segment deviation of either > or = 1 mm or > or = 0.5 mm remained independent predictors of death or MI by 1 year.
Conclusions: The admission ECG is very useful in risk stratifying patients with non-Q wave MI. The new criteria of not only > or = 1-mm ST segment deviation but also > or = 0.5-mm ST segment deviation or LBBB identify high risk patients, whereas T wave inversion does not add to the clinical history in predicting outcome.
Source: PubMed