Relationship between late potentials and the predischarge electrocardiographic pattern in patients with acute anterior wall myocardial infarction

Predischarge ST segment and T wave patterns in predicting left ventricular function and myocardial viability in Q wave anterior myocardial infarction patients

The aim of this study was to investigate the correlation between ECG changes prior to discharge and findings of early low dose dobutamine stress echocardiography (LDSE) performed in 6 +/- 2 days, in patients experiencing their first acute anterior MI. A total of 62 patients admitted with their first acute anterior MI were divided into three groups according to the findings of electrocardiograms performed on the 7-10th days: group A, isoelectric ST and negative or positive T wave; group B, ST elevation (> 0.1 mV) and negative T wave; and group C, ST elevation and positive T wave. There were no significant differences between the groups with respect to thrombolytic therapy and reperfusion criteria. In addition, 90% of the patients in group A (20/22), 66% in group B (12/18, P < 0.05 versus group A), and only 54% in group C (12/22, P < 0.01 versus group A) responded to LDSE. The infarct zone wall motion score index (WMSI) measured by LDSE was significantly decreased in group A compared to basal values (from 2.71 +/- 0.65 to 2.07 +/- 0.71 P = 0.02), and it was significantly different compared to groups B and C. Moreover, the serum creatinine kinase level of the patients in group C was higher (P < 0.01 versus group A), whereas the ejection fraction was inferior (group A 48%, group B 47%, and group C 41%, P = 0.04 versus group A). When the correlations between good left ventricular function and terminal QRS distortion, sum ST elevation, the number of leads with ST elevation, ST elevation shape on admission, and ST and T alterations in ECG at discharge were investigated, an independent correlation was found between ST and T alteration in ECG and a WMSI value < 2 at rest or after LDSE (P = 0.03, OR 3.08, 95%CI 1.05-8.98). At the infarct zone of patients with ST elevation and positive T waves, left ventricular function is worse and the viability is less. This simple classification may be useful in predicting left ventricular function at the time of discharge.

Relationship between myocardial viability and the predischarge electrocardiographic pattern in patients with first anterior wall acute myocardial infarction

BACKGROUND

The assessment of residual viability in the infarcted area after an acute myocardial infarction is relevant to subsequent management and prognosis.

OBJECTIVE

The aim of this study was to investigate the correlation between myocardial viability after an acute anterior myocardial infarction (AMI) as assessed by low dose dobutamine stress echocardiography (LDDSE) and the electrocardiographic patterns of ST segment and T wave abnormalities at the end of the first week of the acute event.

METHODS

Sixty-nine consecutive patients (51 men, 18 women, mean age+/-standard deviation=57+/-11 years) who admitted to our clinic due to a first episode of transmural AMI were included in this study. Two-dimensional echocardiography was performed to all patients during rest and low dose dobutamine administration at the end of the first week of admission (7+/-2 days). Patients were classified into four groups according to ST segment and T wave morphology: group A, ST elevation < or =0.1 mV and negative T waves; group B, ST elevation < or =0.1 mV and positive T waves; group C, ST elevation > or =0.1 mV and negative T waves and group D, ST elevation > or =0.1 mV and positive T waves.

RESULTS

Myocardial viability was detected more often in patients with isoelectric ST segments (22/24, 92%) than those with elevated ST segments (21/45, 47%) (P<0.001). Similarly patients with negative T waves had myocardial viability more frequently compared to those with positive T waves (32/45, 71% vs. 11/24, 46%, P<0.01). Seventeen (94%) of 18 patients in group A and 5 (83%) of six patients in group B had viable myocardium (P>0.05). Myocardial viability was found in 15 (56%) of 27 patients in group C and six (33%) of 18 patients in group D (P<0.01). As a marker of viable myocardium, isoelectricity of ST segment was specific (92%) but only moderately sensitive (51%), with a 92% positive predictive accuracy and a poor (53%) negative predictive value. T wave negativity was less specific but more sensitive than isoelectricity of ST segment for myocardial viability.

CONCLUSION

The presence of isoelectric ST segment and negative T wave indicates a high probability of myocardial viability. However, absence of these electrocardiographic patterns does not exclude the presence of viable myocardium.

The predischarge electrocardiographic pattern in anterior acute myocardial infarction: relation between evolutionary ST segment and T-wave configuration and prediction of myocardial infarct size and left ventricular systolic function by the QRS Selvester score

Left ventricular systolic function, determined mainly by final infarct size, has a major influence on prognosis after acute myocardial infarction (MI). It was found that infarct size and left ventricular ejection fraction can be predicted using the Selvester QRS-score in patients not receiving reperfusion therapy. We assessed whether the predischarge QRS-score can be used for estimating infarct size and left ventricular ejection fraction in 51 patients with a first anterior MI who had received reperfusion therapy and whether considering the configuration of the ST-segments and T-waves will increase the accuracy of these predictions. All patients had received reperfusion therapy and had predischarge resting 99mTc-sestamibi scan. We determined the Selvester QRS score using the electrocardiograms performed on the same day of the scan. In addition, we divided the patients into 3 groups: A: isoelectric ST and negative T-waves (n = 12); B: ST elevation (> or =0.1 mV) and negative T-waves (n = 23); and C: ST elevation (> or =0.1 mV) and positive T-waves (n = 16). The myocardial perfusion defect extent increased from group A to C (28.5+/-16.4%, 39.4+/-14.8%, and 45.3+/-15.8% in groups A, B, and C. respectively; P = .022). Similarly, the left ventricular ejection fraction decreased (41.7+/-11.6%, 38.4+/-8.1%, and 32.0+/-9.7%, respectively; P = .042) from group A to C. Overall, the correlation between the QRS-score and the myocardial perfusion defect extent (Rho = 0.249; P = .08), and ejection fraction (Rho = -0.229; P = .11) was not good. A statistically significant correlation between the myocardial perfusion defect size and the QRS-score was found only in group A (Rho = 0.599, P = .04). In patients with a first anterior myocardial infarction who underwent reperfusion therapy, the predischarge QRS-score is predictive of infarct size only in those in whom ST elevation resolved completely. In patients with residual ST elevation the Selvester QRS-score is inaccurate in predicting infarct size and left ventricular ejection fraction upon discharge.

Relation between evolutionary ST segment and T-wave direction and electrocardiographic prediction of mycardial infarct size and left ventricular function among patients with anterior wall Q-wave acute myocardial infarction who received reperfusion therapy

In the prethrombolytic era it was found that infarct size and left ventricular ejection fraction could be predicted using the Selvester QRS score. We evaluated whether infarct size and left ventricular ejection fraction could be predicted by the predischarge QRS score in patients who had received reperfusion therapy and whether considering the configuration of the ST segments and T waves would increase the accuracy of these predictions. We evaluated 51 patients with first anterior wall myocardial infarction who had received reperfusion therapy and predischarge resting technetium-99m-sestamibi scan. The electrocardiograms recorded on the same day of the scan were analyzed for the QRS score and were divided into 3 groups: A, isoelectric ST and negative T waves; B, ST elevation (> or =0.1 mV) and negative T waves; and C, ST elevation (> or =0.1 mV) and positive T waves. Groups A, B, and C included 12, 23, and 16 patients, respectively. The myocardial perfusion defect extent increased from groups A to C (median 21%, 37%, and 43.5% in groups A, B, and C, respectively; p = 0.023). Similarly, left ventricular ejection fraction decreased (44%, 38%, and 34%, respectively; p = 0.042) from groups A to C. Overall, the correlation between the QRS score and the myocardial perfusion defect extent (rho 0.249; p = 0.08) and ejection fraction (rho -0.229; p = 0.11) was poor. A statistically significant correlation between myocardial perfusion defect size and QRS score was found only in group A (rho 0.599, p = 0.04). Among patients with anterior myocardial infarction who received reperfusion therapy, the predischarge QRS score was predictive of infarct size only in those in whom ST elevation resolved completely. In patients with residual ST elevation there was no correlation between QRS score and infarct size.