The aetiology and prognostic implications of reciprocal electrocardiographic changes in acute myocardial infarction.

Abstract

The relations between reciprocal ST segment depression in the electrocardiogram and infarct size and 10 year prognosis were studied in 315 patients who survived for at least 28 days after a first anterior or inferior myocardial infarction. ST depression was more common in inferior infarcts (72%) than in anterior (37%) ones. It occurred more frequently in complicated infarcts and in the presence of considerable ST elevation. Patients experiencing second or third degree heart block were significantly more likely to show reciprocal changes. The rise in peak cardiac enzyme concentration was higher in patients showing ST depression. In patients with ST depression, peak creatine kinase concentration was 46% higher, aspartate aminotransferase was 39% higher, and lactate dehydrogenase 29% higher after correction for site and complications. A discriminant function analysis selected infarct site, peak aspartate aminotransferase, and magnitude of ST elevation as predictors of the occurrence of ST depression. Age, severity, and smoking status did not significantly improve discrimination. Despite larger increases in peak enzyme concentrations patients with ST depression had marginally fewer subsequent episodes of unstable angina or fatal or non-fatal infarction and a marginally lower 10 year death rate. Neither difference was statistically significant. ST depression occurring early in the acute phase of myocardial infarction is likely to be a reflection of electrophysiological changes taking place at the site of the infarct that is manifested in the contralateral surface of the heart. Other causes, however, such as transient ischaemia at the site of the reciprocal changes or extension of the infarct to contiguous areas cannot be excluded in all cases.

Reciprocal ECG change in reperfused ST-elevation myocardial infarction is associated with myocardial salvage and area at risk assessed by cardiovascular magnetic resonance

“…It has been known for over 20 years that patients with reciprocal ECG changes have larger cardiac enzyme release4 and adverse prognosis 13. The underlying mechanisms have not been well understood.…”

“…Its use in prognostic stratification is limited, aside from assessment of territory and chronicity of infarction. Reciprocal ST segment depression, remote from the infarct site, confers adverse prognosis,1–3 but the causes for these changes have been the subject of long-standing controversy 4. In particular, whether reciprocal change reflects the infarct zone or non-culprit vessel ischaemia is debated.…”

Inferior myocardial infarction. High-risk subgroups.

“…[5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] Approximately one half of the patients who develop heart block do so through a gradual progression of their conduction delay, whereas the remainder abruptly develop the highest degree of heart block they will attain.89,12,15,2' The timing of the onset of the heart block in acute inferior infarction is presented in Table 2. 9,15,16,22,23 Roughly 8% of all patients who have an inferior infarction have highdegree heart block on arrival at the emergency department, and approximately two thirds of the patients who are eventually going to develop highdegree heart block have done so within 24 hours of admission.…”

Angiographic and Clinical Significance of `Transient' ST-Segment Depression in the Lateral Chest Leads in Anterior Wall Acute Myocardial Infarction

“…However, in the present study, there was no difference in the frequency of patients with ST-segment depression in the inferior leads between patients with and without ST-segment depression in the lateral chest leads. Considering the results of the present study and previous studies with regard to STsegment depression in the inferior leads in anterior wall AMI, 4,6,8,12,13,19 there may be some differences in infarct size and prognosis between patients with ST-segment depression in the inferior leads and those with ST-segment depression in the lateral chest leads. Further investigation is Japanese Circulation Journal Vol.63, November 1999 needed to precisely clarify any differences in clinical features according to the site of ST-segment depression in anterior wall AMI.…”

“…Patients with ST-segment depression in the inferior leads in anterior wall AMI have been shown to have a higher incidence of proximal LAD occlusion, 15,18,20,21 a larger infarct size, 4,8,12,13,19 and a poorer prognosis. 6,8,12,19 Therefore, the frequency of patients with ST-segment depression in the inferior leads could affect our results.…”