Reciprocal ST segment changes in acute inferior myocardial infarction: clinical, haemodynamic and angiographic implications

Subepicardial burn injuries in bullfrog heart induce electrocardiogram changes mimicking inferior wall myocardial infarction

Using bullfrog hearts, we previously reproduced a ST segment elevation in electrocardiogram (ECG), mimicking human ischemic heart disease. In the present study, by inducing subepicardial burn injuries on the inferior part of the frog heart ventricle, we could reproduce typical ECG changes observed in human inferior wall myocardial infarction, such as the marked elevation of the ST segments in inferior limb leads (II, III, aVF) and their reciprocal depression in the opposite limb leads (I, aVL). Due to the decrease in Na⁺/K⁺-ATPase protein expression, the resting membrane potential of injured cardiomyocytes shifted toward depolarization. Such induced electrical difference between the injured and intact cardiomyocytes was thought to be responsible for the creation of “currents of injury” and the subsequent ST segment changes.

Relation of collateral circulation with reciprocal changes in patients with acute ST-elevation myocardial infarction

OBJECTIVE

Acute STEMI is often accompanied by reciprocal ST-segment depression (RC) occurring in opposite leads, whose significance has been debated for decades. The possible role of collateral circulation in promoting RC in acute STEMI has not been identified. So our aim to find the relationship between collateral circulation and RC in STEMI patients treated with primary percutaneous intervention (PPCI).

METHODS

The study included 112 pts. with acute STEMI underwent PPCI. The patients divided in to 2 groups: Group (A):66 pts. with RC, Group (B):46 pts without RC. All patients subjected to history taking, ECG [localization of infarction & RC], CKMB level, transthoracic echo [LVEF%], coronary angiography &PPCI to culprit artery and assess number of diseased vessels, site of occlusion, collaterals, TIMI flow pre and post PCI.

RESULTS

Patients in group A with RC had shorter time to door, P < 0.001; more frequent inferior infarctions, P < 0.001; had higher CKMB level, P < 0.001; higher LVEDD, P < 0.001; LVESD, P < 0.001and lower LVEF, P = 0.004; had multi vessel diseases P = 0.02, increase incidence of RCA as a culprit artery <0.001 compared to patients with no RC. Patients with RC had significantly higher incidence of proximal LAD occlusion, distal RCA and distal LCX compared to patients without RC. The percentage of change was 61.2 ± 12.35% for ST elevation and 50.5 ± 10.87% for reciprocal ST depression post PCI with significance difference between them, t = 3.035P = 0.0023.There was no significant correlation between collateral circulation and RC. We found four significant independent predictors of RC. They were inferior infarction (P = 0.024), RCA as a culprit vessel, (P = 0.034), low EF, (P = 0.007) and multi-vessel disease, (P = 0.022).

CONCLUSION

There is no correlation between concomitant RC and presence of collateral vessels in acute STEMI patients. So the pathogenesis of reciprocal ST-segment changes result from an interplay of ischemia at distance due to multi-vessel CAD and benign mirror electrical changes not caused by collateral circulation diverting blood to ischemic area from non-diseased artery.

ST segment elevation in leads V1 to V3 due to isolated right ventricular branch occlusion during primary right coronary angioplasty

It is rare to observe ST elevation in anterior derivations caused by isolated right ventricular branch occlusion. We described the case with acute inferior and right ventricular myocardial infarction (MI) who developed ST segment elevation in precordial leads V(1) to V(3) due to isolated right ventricular branch occlusion during primary right coronary angioplasty.

Maximal precordial ST-segment depression in leads V4-V6 in patients with inferior wall acute myocardial infarction indicates coronary artery disease involving the left anterior descending coronary artery system

BACKGROUND

In inferior wall acute myocardial infarction, maximal ST-segment depression in left precordial leads (V4-V6) has been shown to be associated with increased in-hospital mortality, presumably due to coronary artery disease involving the left anterior descending coronary artery system.

METHODS

We measured ST-segment deviation from baseline in the initial electrocardiogram of patients with inferior wall acute myocardial infarction, who subsequently underwent coronary angiography during their in-hospital stay. Patients were divided into three groups: (I) No precordial ST-segment depression (n = 34). (II) Maximal precordial ST-segment depression in leads V1-V3 (n = 44). (III) Maximal precordial ST-segment depression in leads V4-V6 (n = 14).

RESULTS

The left anterior descending coronary artery or its diagonal branch were stenosed (> 50%) in 32%, 41%, and 71% of patients in groups I, II, and III, respectively (p = 0.04), and severely stenosed (> 70%) in 18%, 18% and 57% of patients in the respective groups (p = 0.007).

CONCLUSION

In patients with inferior wall acute myocardial infarction, maximal precordial ST-segment depression in leads V4-V6 is suggestive of severe coronary artery disease involving the left anterior descending coronary artery or its diagonal branch.

Prognostic significance of precordial ST segment depression on admission electrocardiogram in patients with inferior wall myocardial infarction

OBJECTIVES

This study assessed retrospectively the correlation between the pattern of precordial ST segment depression on the admission electrocardiogram (ECG) and hospital mortality in patients with an inferior myocardial infarction treated with intravenous thrombolytic therapy.

BACKGROUND

Previous studies have shown that in acute inferior myocardial infarction, ST segment depression in the precordial leads is associated with increased hospital mortality. However, the significance of the different patterns of precordial ST segment depression has been evaluated in only two previous studies.

METHODS

The study included 1,321 patients (1,020 men) who enrolled in the Global Utilization of Streptokinase and t-PA for Occluded Coronary Arteries (GUSTO-I) trial in Israel and received intravenous thrombolytic therapy. Patients with an ST segment elevation > or = 0.1 mV in at least two of the inferior leads were included. Patients were classified into four groups on the basis of their admission ECG: group I = patients with no precordial ST segment depression (n = 346); group II = those for whom the sum of ST segment depression in leads V1 to V3 was greater than that in leads V4 to V6 (n = 700); group III = those for whom the sum of ST depression in leads V1 to V3 was equal to that in leads V4 to V6 (n = 162); group IV = those with maximal ST depression in leads V4 to V6 (n = 113).

RESULTS

The overall hospital mortality rate was 3.6% (48 patients): for groups I, II, III and IV it was 2.9%, 2.8%, 4.3% and 9.7%, respectively. Multivariable logistic regression analysis confirmed that hospital mortality was independently associated with the pattern of precordial ST segment depression. The odd ratios in group IV relative to group I was 2.78 (95% confidence interval 1.26 to 6.13, p = 0.007).

CONCLUSIONS

The risk of mortality is higher in patients with an inferior myocardial infarction and maximal ST segment depression in precordial leads V4 to V6 versus precordial leads V1 to V3 on the admission ECG.

Implications of inferior ST-segment depression in anterior acute myocardial infarction: electrocardiographic and angiographic correlation

This study assesses the significance of inferior ST-segment depression during anterior acute myocardial infarction (AMI) by investigating the relationship between inferior ST-segment depression and (1) the site of the left anterior descending (LAD) coronary artery lesion and (2) ST-segment deviation in the various anterior and lateral leads. We studied 126 patients with anterior AMI who underwent coronary angiography within 21 days of hospitalization. The admission 12-lead electrocardiograms were evaluated for ST-segment amplitude in each lead at 0.08 second after the J-point. Coronary angiography was evaluated for the site and severity of luminal narrowing of the coronary arteries. The site of the culprit lesion in the LAD artery, relative to the origin of the first septal and diagonal branches, was determined. In four patients no lesion was identified in the LAD artery. Of the remaining 122 patients, 40 and 53 patients had a LAD artery lesion proximal to the first septal and first diagonal branches, respectively. Additional luminal narrowing (> or = 70% of diameter) was found in the circumflex and the right coronary arteries in 27 and 37 patients, respectively. ST-segment depression of > 1 mm in leads II, III, and aVF was noted in 24, 29, and 24 patients, respectively. The prevalence of a LAD artery preseptal and prediagonal lesion was higher in patients with inferior ST-segment depression.(ABSTRACT TRUNCATED AT 250 WORDS)

Importance of reciprocal ST segment depression in leads V5 and V6 as an indicator of disease of the left anterior descending coronary artery in acute inferior wall myocardial infarction

The purpose of this study was to determine the coronary angiographic correlations (specifically disease of the left anterior descending coronary artery) of reciprocal ST segment depression appearing during inferior acute myocardial infarction. Forty six patients (41 men and five women; mean age 56 years) were allocated into two groups based on the extent of precordial ST segment depression: widespread (V1-V6) ST depression v localised (V1-V4) ST depression. Patients with no reciprocal ST depression or patients with ST depression in V1-V4 but with ST elevation in V5 and V6 (inferolateral acute myocardial infarction) were excluded. All patients were catheterised during hospital admission for infarction. Twenty four of the 28 patients with ST depression in V1-V6 had significant lesions in the left anterior descending coronary artery whereas 16 of the 18 patients with ST depression in V1-V4 had insignificant or no lesions in the left anterior descending artery. The sensitivity, specificity, and positive and negative predictive values of widespread ST depression in predicting disease in the left anterior descending coronary artery were 92%, 80%, and 86% and 89% respectively. In patients with inferior acute myocardial infarction and precordial ST depression, the extent of ST depression is of clinical significance. Widespread (V1-V6) ST depression suggests disease of the left anterior descending coronary artery, whereas localised ST depression (V1-V4) indicates its absence.

ST-segment depression in inferior ECG leads during percutaneous transluminal coronary angioplasty for left anterior descending artery

The mechanism of inferior ST depression during percutaneous transluminal coronary angioplasty (PTCA) for the left anterior descending artery (LAD) was studied in 108 patients with isolated LAD lesion. In 49 patients (Group I) ST depression in inferior leads was observed, and 59 patients (Group II) showed no inferior ST depression. In the lateral lead (I or a VL), the incidence (43 cases; 88% vs. 5 cases; 9%) and degree (1.5 +/- 0.8 mm vs. 0.2 +/- 0.4) of ST elevation were significantly greater in Group I than in Group II. There was a significant inverse correlation (r = -0.57, p less than 0.01) between ST depression in the inferior lead and ST elevation in the lateral lead, but no correlation was found between anterior leads (V2-4) and the inferior leads. Elevation of diastolic pressure of the pulmonary artery (8.7 +/- 4.8 vs. 5.7 +/- 2.8 mmHg) and lowering of systolic pressure of the femoral artery (-25.7 +/- 24.3 vs. -11.8 +/- 8.3 mmHg) were significantly greater in Group I. These findings suggest that ST depression in the inferior leads during LAD angioplasty was due to a purely electrical phenomenon and not to the concomitant ischemia of the inferior wall. However, this change was more frequently seen in patients with larger myocardial ischemia and, presumably, was more often related to ST elevation in the lateral lead, which is reciprocal in position.