Dobutamine-induced ST-segment elevation in patients with acute myocardial infarction and the role of myocardial ischemia, viability, and ventricular dyssynergy

Exercise-induced ST-segment elevation in patients with a recent acute myocardial infarction treated by primary percutaneous coronary intervention

OBJECTIVES

To get insight in the mechanism of exercise-induced ST-segment elevation (STE) in patients with Q/QS waves at the electrocardiogram (ECG).

METHODS

We performed exercise stress test in 13 patients with anterior acute myocardial infarction treated by successful primary percutaneous coronary intervention (PCI).

RESULTS

Compared to rest, an additional STE > or = 1 mm in one or more precordial ECG leads during exercise occurred in nine patients (69%), in the absence of symptoms.

CONCLUSIONS

In acute myocardial infarction (MI) patients, treated by primary PCI and showing optimal coronary blood flow restoration at angiography, STE can still be induced by exercise in Q/QS wave ECG leads. This finding lends further support to the theory that exercise-induced STE in this clinical context is unlikely to represent by itself transient myocardial ischemia or viability.

A modified electrocardiographic algorithm for differentiating typical atrioventricular node re-entrant tachycardia from atrioventricular reciprocating tachycardia mediated by concealed accessory pathway

Non-invasive prediction of tachycardia mechanism is becoming clinically important in the era of catheter ablation for curing supraventricular tachycardia. Twelve-lead electrocardiograms (ECGs) during sinus rhythm and atrioventricular node re-entrant tachycardia (AVNRT) or atrioventricular reciprocating tachycardia (AVRT) with a narrow QRS complex were obtained from 154 consecutive adult patients who had received successful radiofrequency catheter ablation. The ECGs of initial 104 patients were analysed by three observers without knowledge of the electrophysiological diagnosis. The two arrhythmias were accurately diagnosed in 68% of cases. Three criteria were found to be discriminators of tachycardia mechanism by univariable analysis. Pseudo r/Q/S waves predicated AVNRT in 92% of cases (sensitivity 71%; specificity 95%). Retrograde P wave predicated AVRT in 86% of cases (sensitivity 75%; specificity 85%), RP interval > or =100 ms in 93% (sensitivity 71%; specificity 94%) and ST-segment elevation in lead aVR in 83% (sensitivity 71%; specficity 83%). According to the initial results, we proposed a modified stepwise ECG algorithm which used pseudo r/S/Q waves, RP interval and ST-segment elevation in lead aVR during tachycardia. Two observers assessed the modified algorithm in the remaining 50 patients. The algorithm was able to correctly diagnose the tachycardia mechanism in 84% and 87%, respectively. Using the modified algorithm can improve the accuracy and simplify the differential diagnosis between typical AVNRT and AVRT via concealed accessory pathway in adult patients.

Prognostic significance of ST-segment elevation during dobutamine stress echocardiography

BACKGROUND

Limited data are available concerning the significance of ST-segment elevation during dobutamine stress echocardiography (DSE). The purpose of this study was to assess the prognostic significance of new ST-segment elevation during DSE and its relationship to angiographic severity of coronary artery disease (CAD).

METHODS

From 4240 consecutive patients who had DSE, we identified 134 (3%) patients with new stress-induced ST-segment elevation > or =1 mm in at least two contiguous electrocardiographic leads. Significant CAD was considered as > or =50% diameter obstruction by angiography. Follow-up was obtained for cardiac events.

RESULTS

Age was 69 +/- 10 years; 84 (63%) were men. ST-segment elevation developed in the anterior leads in 55 (41%), inferior leads in 100 (75%), and lateral leads in 54 (40%); 56 (42%) had ST elevation in more than one region. Dobutamine stress echocardiography was abnormal in all patients; 115 (86%) had ischemia. Coronary angiography was obtained in 69 (51%) patients. Stenosis was > or =70% diameter in 68 (99%) patients and multivessel in 53 (77%). Follow-up (2.6 +/- 2.8 years) was obtained in all 134 patients. Events occurred in 103 (77%) patients, including death in 53, coronary revascularization in 33, myocardial infarction in 12, and unstable angina in 5. Event-free survival was 55% at 2 years, 38% at 4 years, and 28% at 5 years.

CONCLUSIONS

Patients with stress-induced ST-segment elevation during DSE commonly have severe CAD and are at high risk for events during follow-up. These patients should be considered for coronary angiography.

Role of right-sided chest leads in the detection of multivessel coronary artery disease in patients with extended Q-wave anterior myocardial infarction

OBJECTIVE

To evaluate the improvement of diagnostic ability of exercise testing to detect multivessel coronary artery disease in patients with extended Q-wave anterior myocardial infarction, using additional right-sided chest leads.

METHODS

Fifty-two consecutive patients with Q-wave anterior myocardial infarction underwent exercise testing, using the standard 12 and the additional right-sided (V3R, V4R, V5R) chest leads, thallium-201 scintigraphy and coronary arteriography.

RESULTS

Twenty-one (40%) patients had one-vessel disease, 18 (35%) had two-vessel disease and 13 (25%) had three-vessel disease. The sensitivities of the standard 12-lead exercise testing and its combination with the additional right-sided chest leads were 24% (5/21) versus 28% (6/21) for the detection of one-vessel disease (P: NS), 33% (6/18) versus 83% (15/18) for the detection of two-vessel disease (P<0.05) and 38% (5/13) versus 92% (12/13) for the detection of three-vessel disease (P<0.05), respectively. In thallium-201 scintigraphy, 29 of the 31 (94%) patients with multivessel coronary artery disease demonstrated reversible ischemia. The usual 12-lead exercise testing could detect ischemia in 11 (35%) of these 31 patients, while the addition of the right-sided chest leads could detect ischemia in 27 (87%) of them (P<0.05).

CONCLUSIONS

The additional right-sided chest leads significantly improve the low sensitivity of the usual exercise testing to detect multivessel coronary artery disease in patients with previous extended Q-wave anterior myocardial infarction.

Significance of exercise-induced ST segment elevation in Q leads in patients with a recent myocardial infarction and an open infarct-related artery

AIMS

The significance of exercise-induced ST segment elevation in Q leads in patients with a recent myocardial infarction and without significant residual stenosis in the infarct-related artery has not been defined. We aimed to elucidate the role of myocardial perfusion and viability in this scenario.

METHODS AND RESULTS

Sixty-six patients with a first myocardial infarction, single-vessel disease and an open artery were studied. Myocardial perfusion was assessed with angiographic blush, intracoronary myocardial contrast echocardiography and magnetic resonance. Myocardial viability was quantified by means of magnetic resonance (transmural extent of necrosis). Exercise-induced ST elevation in Q leads was observed only in 13 cases (20%); 53 patients (80%) did not show this finding. The group with ST elevation had fewer cases with normal perfusion: Blush 3 (15% vs. 74%, p=0.001), myocardial contrast echocardiography score >0.75 (8% vs. 81%, p=0.001) and magnetic resonance score >0.75 (31% vs. 68%, p=0.03). Similarly, myocardial viability (necrosis <50%) was less frequent in patients with ST elevation (8% vs. 72%, p=0.001).

CONCLUSION

In patients with a first myocardial infarction and without residual ischemia, exercise-induced ST segment elevation in Q leads is an uncommon finding and it is related to a more damaged coronary microcirculation and to less viable myocardium.

Exercise-induced prolongation of the infarct-related Q-waves as a marker of myocardial viability in the infarcted area

OBJECTIVE

It is known that exercise-induced ischemia in patients with coronary artery disease (CAD) may produce QRS prolongation in the surface electrocardiogram (ECG). To investigate the presence of exercise-induced Q-wave prolongation in patients with single-vessel CAD and Q-wave myocardial infarction (MI), in association with the presence of reversible perfusion defects during thallium scintigraphy in the infarcted area.

METHODS

107 consecutive patients (89 males, mean age 56+/-8 years) were evaluated. All patients underwent coronary arteriography, maximal treadmill exercise testing and thallium-201 scintigraphy. Q-wave duration was measured both before exercise testing and during maximal heart rate from 12-lead ECGs recorded with a paper speed of 50 mm/s.

RESULTS

Only 57 out of the 107 studied patients showed reversible perfusion defects in the infarcted area during thallium scintigraphy. Q-wave duration was significantly increased from the resting to the stress ECG (DeltaQ-wave duration) in patients with reversible perfusion defects in the infarcted areas (10+/-13 ms), but not in patients with fixed defects in the infarcted zone (-2.0+/-5 ms, p<0.01). The sensitivities and the specificities of Q-wave prolongation, ST segment elevation, and the combination of ST segment elevation with ST segment depression in the reciprocal leads for the detection of myocardial viability in the infarcted area were 82%, 48%, 29% and 88%, 50%, and 90%, respectively.

CONCLUSIONS

Exercise-induced Q-wave prolongation is demonstrated in those patients with single-vessel CAD and a recent MI who show reversible perfusion defects in thallium scintigraphy. Exercise-induced Q-wave prolongation was found to be a sensitive and specific ECG marker for the detection of myocardial viability in the infarcted area.

Usefulness of ST-segment elevation in lead aVR during tachycardia for determining the mechanism of narrow QRS complex tachycardia

In the present study, we analyzed ST-segment elevation in lead aVR during tachycardia to differentiate the narrow QRS complex tachycardia. A total of 338 12-lead electrocardiograms during narrow QRS complex tachycardia were analyzed. Each patient underwent a complete electrophysiologic study. There were 161 episodes of atrioventricular nodal reentrant tachycardia (AVNRT), 165 episodes of atrioventricular reciprocating tachycardia (AVRT), and 12 episodes of atrial tachycardia (AT). The prevalence of aVR ST-segment elevation was 71% for AVRT, 31% for AVNRT, and 16% for AT. For ST-T changes in different leads, logistic regression analysis showed aVR ST-segment elevation was the only significant factor to differentiate the types of narrow QRS complex tachycardia (p<0.001 for AVRT and AVNRT; p=0.02 for AVRT and AT). The sensitivity, specificity, and accuracy of aVR ST-segment elevation to differentiate AVRT from AVNRT and AT were 71%, 70%, and 70%, respectively. Among 117 episodes of AVRT with aVR ST-segment elevation, there were 76 (65%) left side, 23 (20%) right side, 14 (12%) posterior septal, and 4 (3%) antero- and mid-septal accessory pathways (p=0.002). In conclusion, aVR ST-segment elevation during narrow QRS complex tachycardia favors the atrioventricular reentry through an accessory pathway as the mechanism of the tachycardia.

Contribution of the sST elevation/T-wave normalization in Q-wave leads during routine, pre-discharge treadmill exercise test to patient management and risk stratification after acute myocardial infarction: a 2.5-year follow-up study

OBJECTIVES

This study investigated whether ST-segment elevation and T-wave normalization (TWN) in Q-wave leads on pre-discharge exercise electrocardiogram (ECG) can contribute to patient management after a recent myocardial infarction (MI).

BACKGROUND

The clinical relevance of these exercise ECG changes remains controversial despite accumulating evidence of their association with myocardial viability. Because discrepancies of previous studies may depend on patient selection, the value of these ST/T abnormalities in the thrombolytic era should be better defined.

METHODS

One-hundred one patients, age 58 +/- 11 years, with a recent, first Q-wave MI (57% thrombolyzed, ejection fraction 43 +/- 7%) underwent pre-discharge, submaximal treadmill testing followed, in the absence of severe ischemia, by dobutamine stress echocardiography, thallium-201 single photon emission computed tomography, and coronary angiography.

RESULTS

ST elevation at peak exercise, but not TWN, was associated with more severe infarctions as indicated by higher peak creatine kinase (p < 0.05) and with a greater number of scarred segments both on echocardiography (p < 0.05) and scintigraphy (p < 0.01). However, the incidence of myocardial viability and ischemia did not differ between groups with or without these ST/T changes. Anterior infarction location and >or=3 echocardiographically scarred segments were among the independent predictors of ST elevation at peak ergometric exercise. During follow-up (31 +/- 13 months), the rate of hard events was low (8%) and similar between the study groups.

CONCLUSIONS

In patients after acute Q-wave MI without severe ischemia according to clinical and standard ECG criteria, exercise-induced ST elevation, but not TWN, is associated with larger infarctions. The contribution of these ST/T abnormalities toward identifying patients with myocardial viability or ischemia and determining risk stratification is poor. In-hospital management of such patients based on routine clinical practice is sufficient for selection of a population with a relatively low long-term risk.

Stress-induced ST-segment elevation following myocardial infarction and its role in wall motion abnormality, myocardial ischemia and viability: comparison of response to exercise, dobutamine and dipyridamole

Stress-induced ST-segment elevation following myocardial infarction (MI) has been correlated with myocardial ischemia, viability and wall motion abnormality, but its mechanism is still unclear, so the present study compared ST-segment elevation and wall motion response during exercise, dobutamine and dipyridamole stresses. Twenty-five patients with their first anterior MI underwent exercise, dobutamine and dipyridamole echocardiography on different days 4-6 weeks after MI. Left ventricular wall motion was analyzed using 5-grade/16-segment model and myocardial ischemia was considered as a worsening of the wall motion score index (WMSI) during the stress test; myocardial viability was defined as a reduction of WMSI during low dose dobutamine. Dyskinesis formation was defined by visual analysis as akinesis that became dyskinetic or if the dyskinesis worsened. Both exercise and dobutamine induced ST-segment elevation, but dipyridamole did not. There was no significant difference in the degree of ST-segment elevation between the patients with and without myocardial ischemia or dyskinesis formation. Exercise induced a higher ST-segment elevation in patients with myocardial viability than those without (0.17+/-0.09 mV vs 0.09+/-0.07 mV, p<0.05). Exercise-induced ST-segment elevations correlated with dobutamine-induced ST-segment elevations (p<0.01), changes in heart rate (p<0.05) and systolic blood pressure (p<0.05). In conclusions, stress-induced ST-segment elevation does not correlate with either myocardial ischemia or stress-induced dyskinesis, but may be associated with myocardial viability.

Exercise-induced ST-elevation is related to left ventricular dysfunction but not to myocardial viability in patients with healed myocardial infarction

BACKGROUND

Exercise-induced ST-segment elevation was proposed as a marker of myocardial viability after a recent myocardial infarction.

AIMS

The aim of this study was to evaluate whether exercise-induced ST segment elevation is related to viability or to left ventricular dysfunction in patients with history of old Q wave myocardial infarction.

METHODS

Fifty patients (43 men, age 57+/-11 years) were studied 31+/-49 months after a Q wave myocardial infarction. They all underwent stress, reinjection-redistribution, and late redistribution Tl-201 SPECT, completed by equilibrium radionuclide angiography. Viability was defined by defect reversibility or significant (>60%) persistent Tl-201 uptake in dyssinergic segments on late redistribution SPECT. Relative post-exercise and reinjection-redistribution LV volumes were calculated using validated software (QGS).

RESULTS

Twenty-one out of 50 patients (42%, G1) had significant stress-induced ST-elevation (>1 mm 80 ms after J point in at least 2 ECG leads with Q wave), and 29/50 (58%, G2) did not. Seventeen out of 50 patients (34%) demonstrated myocardial viability on late redistribution scan. The diagnostic accuracy of exercise-induced ST-elevation was only 52% for viability assessment. Significant LVEF reduction and increased relative LV volumes were observed in G1 compared to G2 (LVEF: 39+/-10% vs. 49+/-11%, P=0.003; post-stress LV volume: 134+/-98 ml vs. 81+/-41 ml, P<0.02; reinjection-redistribution LV volume: 123+/-86 ml vs. 79+/-40 ml; P<0.02). Perfusion defects were similar in G1 and G2 (post-exercise: 38+/-12% vs. 37+/-14%, ns; reinjection-redistribution: 31+/-11% vs. 30+/-11%, ns; late redistribution: 30+/-10% vs. 28+/-11%, ns).

CONCLUSION

These results suggest that, in patients with history of myocardial infarction, exercise-induced ST-segment elevation is not related to persistent myocardial viability but is associated to left ventricular dysfunction.

ST-segment elevation on Q-leads during exercise in patients with ST-segment elevation at rest after myocardial infarction

INTRODUCTION

ST-segment elevation on Q-leads after an acute myocardial infarction is related to a greater infarct size. The meaning of a further exercise-induced ST-segment elevation in these patients has not been analyzed.

METHOD

Thirty-six patients with ST-segment elevation on Q-leads were studied after a first acute myocardial infarction. Exercise testing and cardiac catheterization were performed at the first week. Left ventricular volumes (ml/m(2)); the extent of abnormal wall motion (AWM: chords); contractile reserve (AWM improvement with low dose dobutamine) and coronary patency in the culprit artery were analyzed. Cardiac catheterization was repeated at the sixth month in 20 patients; systolic recovery (AWM improvement), left ventricular volumes and coronary patency were again evaluated.

RESULTS

Patients with exercise-induced ST-segment elevation in two or more Q-leads (n=21) showed lesser contractile reserve (6+/-6 vs. 12+/-7 chords, P=0.01) than patients without exercise-induced ST-segment elevation (n=13). AWM (F=8.1) and absence of exercise-induced ST-segment elevation (F=9.5; positive predictive value: 80%; negative predictive value: 68%) were the only independent predictors of contractile reserve. Nevertheless, this electrocardiographic sign was not related to left ventricular volumes, coronary patency or systolic function and it did not predicted late systolic recovery.

CONCLUSIONS

In patients with baseline ST-segment elevation on Q-leads an exercise-induced ST-segment elevation is independently related to a lesser contractile reserve but not to the evolution of volumes or regional dysfunction during the first 6 months post-infarction. Therefore, the clinical value of this sign seems to be limited to the non-invasive detection of myocardial viability during the early post-infarction phase.

Prognostic usefulness of dobutamine-induced ST-segment elevation and T-wave normalization after uncomplicated acute myocardial infarction

We followed 229 consecutive patients exhibiting negative T waves on infarct-related electrocardiographic leads; these patients underwent dobutamine stress echocardiography within 10 days after a first uncomplicated acute myocardial infarction. T-wave normalization, but not ST-segment elevation, recognized patients at higher risk of cardiac events and optimized the prognostic accuracy of both myocardial viability and ischemia, to which it was correlated and became an independent predictor in cases of subdiagnostic stress echocardiography.

Significance of dobutamine-induced ST-segment evaluation and T-wave pseudonormalization in patients with Q-wave myocardial infarction: simultaneous evaluation by dobutamine stress echocardiography and thallium-201 SPECT

The clinical significance of stress-induced ST-segment elevation and T-wave pseudonormalization in infarct-related leads is still controversial. Therefore, we conducted the present study to assess this issue using simultaneous dobutamine stress echocardiography (DSE) and thallium-201 single-photon emission computed tomography. A total of 119 patients with Q-wave myocardial infarction were enrolled in this study. There were 58 patients with (group I) and 61 patients without (group II) dobutamine-induced ST-T changes. Left ventricular ejection fraction was 43 +/- 13% in group I and 49 +/- 14% in group II (p <0.05). The baseline, low-, and peak-dose global wall motion scores were similar between these 2 groups (26.2 +/- 6.1 vs 26.2 +/- 6.3 [p = NS]; 24.1 +/- 5.3 vs 23.5 +/- 5.7 [p = NS]; 26.4 +/- 5.7 vs 26.7 +/- 6.1 [p = NS]). The sensitivity, specificity, and accuracy of these ST-T changes for detecting residual myocardial viability and ischemia documented by DSE in all patients were 50%, 53%, and 51% (for viability), and 47%, 48%, and 47% (for ischemia), respectively. The sensitivity, specificity, and accuracy of these ST-T changes for detecting a reversible perfusion defect documented by thallium-201 single-photon emission computed tomography were 51%, 54%, and 52%, respectively. In conclusion, dobutamine-induced ST elevation and/or T-wave pseudonormalization is associated with poor resting left ventricular function. These ST-T changes are not associated with residual myocardial ischemia and viability in the infarct area. Therefore, these electrocardiographic changes alone cannot be reliably considered as distinctive markers in formulating the therapeutic strategy of coronary intervention.

ST-segment elevation on Q leads at rest and during exercise: relation with myocardial viability and left ventricular remodeling within the first 6 months after infarction

BACKGROUND

Resting ST-segment elevation on Q leads after an acute myocardial infarction has been related to a greater infarct size. Otherwise, the relation between exercise-induced ST-segment elevation and myocardial viability is controversial. We investigated the relation between ST-segment elevation on Q leads at rest and during exercise and regional dysfunction and its evolution, contractile reserve, left ventricular dilation, and coronary patency.

METHODS AND RESULTS

Exercise testing and cardiac catheterization were performed at the first week after infarction in 51 patients. The study group was divided according to the existence (in 2 or more Q leads; n = 36) or not (n = 15) of resting ST-segment elevation and according to the existence (n = 28) or not (n = 23) of exercise-induced ST-segment elevation. Left ventricular end-diastolic and end-systolic volumes (mL/m2), regional wall motion (SD/chord), contractile reserve (wall motion percentage improvement with low-dose dobutamine), and coronary patency in the culprit artery were analyzed. Cardiac catheterization was repeated at the sixth month in 35 patients; systolic recovery (wall motion percentage improvement), left ventricular volumes, and coronary patency were again evaluated. Patients with resting ST-segment elevation showed poorer wall motion (2.1 +/- 0.8 SD/chord vs 1.2 +/- 1 SD/chord, P =.002), lesser contractile reserve (17% [0% to 39%] vs 41% [4% to 92%], P =.04), greater end-systolic volume (32 +/- 15 mL/m2 vs 23 +/- 11 mL/m2, P =.04), and higher percentage of occlusion (36% vs 7%, P =.04) than did patients without ST-segment elevation. Likewise, patients with exercise-induced ST-segment elevation showed lesser contractile reserve (8% [0% to 40%] vs 35% [12% to 86%], P =.03) than did patients without exercise-induced ST-segment elevation. The only independent predictors of contractile reserve were wall motion <2 SD/chord (odds ratio [OR] 7.1, confidence interval [CI] 6.3 to 7.9, P =.01) and the absence of exercise-induced ST-segment elevation (OR 5.7, CI 4.9 to 6.5, P =. 02). There were no significant differences between patients with and those without ST-segment elevation (at rest or during exercise) in systolic recovery or left ventricular volumes at the sixth month.

CONCLUSIONS

ST-segment elevation on Q leads at rest is related to a poorer systolic function (more severe regional dysfunction, greater end-systolic volume, and less response to dobutamine). ST-segment elevation during exercise is independently related to a lesser contractile reserve. ST-segment elevation (at rest or during exercise) is not related to the evolution of volumes or regional dysfunction during the first 6 months after infarction.

Echocardiographic studies of dobutamine-induced ST-segment elevation before and after coronary artery bypass grafting in patients with old Q-wave myocardial infarction

There is a controversy regarding the functional significance of stress-induced ST-segment elevation (STE) in Q leads. However, the effect of revascularization on the induction of STE was not investigated. We studied 35 patients with old Q-wave myocardial infarction who underwent coronary artery bypass grafting (CABG) of the infarct-related artery with dobutamine (up to 40 microg/kg per minute) stress echocardiography before and 3 months after CABG. Ischemia was defined as new or worsened wall motion abnormalities. Functional recovery was defined as a reduction of regional wall motion score of 1 or more in 2 or more segments from the pre-CABG to post-CABG resting echocardiogram with the use of the 16-segment/5-grade score model. STE (>/=0.1 mV J-point elevation lasting 80 ms in >/=2 Q leads) occurred in 20 (57%) patients. There was no significant difference between patients with and those without STE before CABG with regard to the prevalence of peri-infarction ischemia (85% vs 80%) or index of improvement of regional function after CABG (0.26 +/- 0.26 vs 0.29 +/- 0.33). STE was reinduced to the same level in 4 patients after CABG, whereas 16 patients showed absent reinduction (8 patients) or reduced level (8 patients) of STE. Functional changes associated with absent reinduction or less STE after CABG were absence of reinduction of regional ischemia in 13 patients, improvement of resting regional function in 5 patients, and resection of scarred segments in 4 patients. Among the 4 patients with persistent dobutamine-induced STE, 1 patient had persistent ischemia and 2 showed worsening of resting regional function. Although dobutamine-induced STE in patients with old Q-wave infarction referred for CABG cannot identify patients with a higher prevalence of ischemia, the lack of reinduction of this pattern after CABG correlates with absent reinduction of ischemia in most of patients.

Significance of exercise-induced ST-segment elevation and T-wave pseudonormalization for improvement of function in healed Q-wave myocardial infarction

Exercise-induced ST-segment elevation and pseudonormalization of negative T waves (ST-T segment changes) in infarct leads indicate myocardial viability after Q-wave myocardial infarcts in some patients and may therefore identify patients who will benefit from revascularization. Global left ventricular ejection fraction and wall motion abnormalities of the left ventricle were analyzed in 34 patients with healed myocardial infarction (11 patients with ST-segment elevation, 3 patients with pseudonormalization of the negative T wave (group 1), and in 20 patients without ST-T segment changes during an exercise electrocardiogram (group 2)) before and 4 months after successful revascularization. Wall motion abnormality in the central infarct region at baseline was similar in both groups (-3.1 +/- 0.6 SD vs 3.0 +/- 0.8 SD; NS). At repeat angiography, wall motion abnormality improved significantly from -3.1 +/- 0.6 SD to -2.1 +/- 0.6 SD (p <0.01) in group 1 and was unchanged in group 2 (-3.0 +/- 0.8 SD vs -2.9 +/- 0.7 SD; NS). Similarly, ejection fraction at control angiography had increased from 54 +/- 14% to 66 +/- 12% (p <0.01) in group 1, but decreased from 56 +/- 9% to 55 +/- 9% in group 2 (NS). Exercise-induced ST-T segment changes yielded a sensitivity of 80% and a specificity of 89% to predict significant improvement of the left ventricular ejection fraction. Exercise-induced changes of the ST-T segment identify patients with a high probability of improvement of myocardial function after revascularization in patients with healed myocardial infarcts.