Severity of residual stenosis of infarct-related lesion and left ventricular function after single-vessel anterior wall myocardial infarction: implication of ST-segment elevation in lead aVL of the admission electrocardiograms

The relationship of the changes in lateral leads I and aVL in electrocardiogram with echocardiography and coronary angiography findings in patients with acute coronary syndrome

BACKGROUND

Electrocardiographic (ECG) study is a principle for the symptoms contributed to the acute myocardial infarction (AMI)/acute coronary syndrome (ACS). The diagnosis of involved coronary artery based on ECG changes is still a challenge. This study is aimed to evaluate the association of mere changes in I and aVL leads with the involved region found through echocardiography and involved coronary artery through angiography.

METHODS

This cross-sectional study was conducted on 100 patients referred with AMI/ACS symptoms that had mere ECG changes in I and aVL leads (ST elevation + Q wave/ST depression + inverted-T). Transthoracic echocardiography (TTE) and coronary angiography (CAG) were performed for the patients. The correlation of ECG with echocardiography and angiography was assessed.

RESULTS

Among the studied population, 39 patients (39%) were women with the mean ± standard deviation (SD) of age of 64.60 ± 9.39 years. There was no significant association between ECG changes in leads I and aVL with neither the stenosis of first diagonal (D1) coronary artery found through angiography (P = 0.580) nor the mid-anterior wall dyskinesia found through echocardiography (P = 0.380). A remarkable association between the echocardiographic findings representing mid-anterior wall ischemic dyskinesia with the stenosis of D1 coronary artery was detected (P < 0.001). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 100%, 54.54%, 94.68%, and 100% were respectively found as the diagnostic values of mentioned factors.

CONCLUSION

Our findings showed significant association between D1 involvement and mid-anterior dyskinesia in echocardiography, while the changes in ECG were associated neither with echocardiographic nor angiographic outcomes.

Comparison of Clinical Outcomes between the Ostial Versus Non-Ostial Culprit in Proximal Left Anterior Descending Artery Acute Myocardial Infarction

Percutaneous coronary interventions to the proximal left anterior descending artery (pLAD)-acute myocardial infarction (AMI) are still challenging, especially in the ostial pLAD. Clinical outcomes of the ostial pLAD-AMI were not well investigated. The aim of the present study was to compare clinical outcomes of the ostial pLAD-AMI with those of the non-ostial pLAD-AMI. The primary endpoint was the major cardiovascular events (MACE), defined as the composite of cardiac death, AMI, stent thrombosis (ST), target lesion revascularization (TLR), and target vessel revascularization (TVR). Between January 2009 and March 2016, a total of 401 pLAD-AMI were included as the study population and were divided into 78 ostial pLAD-AMI (the ostial pLAD group), and 323 non-ostial pLAD-AMI (the non-ostial pLAD group). The median follow-up duration was 414 days. The MACE tended to be higher in the ostial pLAD group (8.0% at 30 days, 19.9% at 400 days) than in the non-ostial pLAD group (4.4% at 30 days, 12.9% at 400 days) without reaching statistical significance (P = 0.087). The prevalence of cardiac death was significantly higher in the ostial pLAD group (6.6% at 30 days, 9.5% at 400 days) as compared with the non-ostial pLAD group (3.1% at 30 days, 4.5% at 400 days) (P = 0.034). There were no significant differences in ST, AMI, TLR, or TVR. We concluded that, as compared with the non-ostial pLAD-AMI, the clinical outcomes of the ostial pLAD-AMI, especially cardiac death, tended to be worse, requiring special attention to the ostial pLAD-AMI.

The significance of ST-elevation in aVL in anterolateral myocardial infarction: An assessment by cardiac magnetic resonance imaging

BACKGROUND

Anterolateral myocardial infarction (MI) is traditionally defined on the electrocardiogram by ST-elevation (STE) in I, aVL, and the precordial leads. Traditional literature holds STE in lead aVL to be associated with occlusion proximal to the first diagonal branch of the left anterior descending coronary artery. However, concomitant ischemia of the inferior myocardium may theoretically lead to attenuation of STE in aVL. We compared segmental distribution of myocardial area at risk (MaR) in patients with and without STE in aVL.

METHODS

We identified patients in the MITOCARE study presenting with a first acute MI and new STE in two contiguous anterior leads from V₁ to V₆ , with or without aVL STE. Patients underwent cardiac magnetic resonance imaging 3-5 days after acute infarction for quantitative assessment of MaR.

RESULTS

A total of 32 patients met inclusion criteria; 13 patients with and 19 without STE in lead aVL. MaR > 20% at the basal anterior segment was seen in 54% of patients with aVL STE, and 11% of those without (p = 0.011). MaR > 20% at the apical inferior segment was seen in 62% and 95% of patients with and without aVL STE, respectively (p = 0.029). The total MaR was not different between groups (44% ± 10% and 39% ± 8.3% respectively, p = 0.15).

CONCLUSION

Patients with anterior STEMI and concomitant STE in aVL have less MaR in the apical inferior segment and more MaR in the basal anterior segment.

The Relationship between Coronary Artery Movement Type andStenosis Severity with Acute Myocardial Infarction

INTRODUCTION

The severity of coronary artery stenosis which leads to myocardial infarction (MI) has been a matter of controversy. Historical data are in favor of mild luminal stenosis (<50% diameter stenosis) while recent studies suggest hemodynamically-significant coronary stenosis as the main substrate for subsequent MI. Also, mechanical stress resulted from coronary artery movement (CAM) may be responsible for plaques rupture. In this study, we evaluated the severity of plaques leading to MI and common CAM patterns in the involved coronary segments.

METHODS

In a cross-sectional descriptive-analytical study, on patients with acute ST-segment myocardial infarction (STEMI) undergoing coronary angiography, the relationship between coronary artery movement type and stenosis severity with acute MI was evaluated. Lesions with stenosis diameter greater than 50 percent were defined as moderate and those equal or higher than 70% were defined as severe stenosis. Three different patterns of coronary artery motion including compression, bending and displacement types were evaluated in segments with culprit lesion.

RESULTS

One hundred and sixty two patients were enrolled. Ninety patients (55.6%) were male and 72 (44.4%) were female. Mean age of the patients was 60.56±13.43 years. In terms of Infarct related lesions (IRLs), 86% of the cases had at least moderate stenosis and in 67%, severe stenosis was present. More than 50% stenosis was found in all patients with anterior STEMI involving LAD. Among three types of coronary motion patterns, compression pattern was significantly higher in LAD (P<0.001), RCA (P<0.001), Diagonal artery (P<0.001) and OM branch (P=0.044), but not in proper LCX (P=0.307).

CONCLUSION

Most of the lesions leading to myocardial infarction have a diameter stenosis of at least 50% and mainly are located in the coronary segments with compression movement pattern.

Relation of lateral ST-segment elevation pattern to myocardial salvage in patients with recanalized anterolateral acute myocardial infarction

BACKGROUND

Although anterior acute myocardial infarction (AMI) with ST-segment elevation in lateral leads is associated with a poor prognosis, the significance of the pattern of lateral ST-segment elevation has not been examined.

HYPOTHESIS

The aim of the study was to examine the relation of the pattern of lateral ST-segment elevation to myocardial reperfusion and infarct size in patients with AMI.

METHODS

We studied 111 patients who had a first AMI presenting with anterolateral ST-segment elevation and Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow of the left anterior descending coronary artery within 6 h from symptom onset. Patients were classified into two groups according to the pattern of lateral ST-segment elevation on the admission electrocardiogram: Group 1, 42 patients with equivalent or greater ST-segment elevation in lead I than in lead aVL, and Group 2, 69 patients with lesser ST-segment elevation in lead I in than in lead aVL. Left ventricular ejection fraction (LVEF) was measured by predischarge left ventriculography.

RESULTS

There were no differences between the two groups in age, gender, time from onset to recanalization, culprit lesion, or collateral development. Group 1 patients had a higher probability of impaired myocardial reperfusion as indicated by a myocardial blush grade of 0 or 1 after recanalization, a higher peak creatine kinase level, and a lower LVEF than Group 2 patients (p = 0.0001, respectively).

CONCLUSIONS

We conclude that equivalent or greater ST-segment elevation in lead I than in lead aVL is associated with impaired myocardial reperfusion and less myocardial salvage in patients with recanalized AMI who present with anterolateral ST-segment elevation on the admission electrocardiogram.

ST-segment depression in lead aVR predicts predischarge left ventricular dysfunction in patients with reperfused anterior acute myocardial infarction with anterolateral ST-segment elevation

BACKGROUND

Patients with an anterolateral acute myocardial infarction (AMI) have a worse prognosis, and those with additional inferolateral wall involvement might be higher risk because of more extensive area at risk. Lead -aVR obtained by inversion of images in lead aVR has been reported to provide useful information for inferolateral lesion.

METHODS

We examined the relation between ST-segment deviation in lead aVR on admission electrocardiogram (ECG) and left ventricular function in 105 patients with an anterolateral AMI undergoing successful reperfusion < or = 6 hours after onset. Patients were classified according to ST-segment deviation in lead aVR on admission ECG: group A, 23 patients with ST elevation of > or = 0.5 mm; group B, 47 patients without ST deviation; and group C, 35 patients with ST depression of > or = 0.5 mm.

RESULTS

There were no differences among the 3 groups in age, sex, or site of the culprit lesion. In groups A, B, and C, the peak creatine kinase level was 3661 +/- 1428, 4440 +/- 1889, and 6959 +/- 2712 mU/mL, and the left ventricular ejection fraction (LVEF) measured by predischarge left ventriculography was 54% +/- 9%, 48% +/- 7%, and 37% +/- 9%, respectively(P < .01). During hospitalization, congestive heart failure occurred more frequently in group C than in groups A or B (P < .05). ST-segment depression in lead aVR had a higher predictive accuracy than other ECG findings in identifying patients with predischarge LVEF < or = 35%.

CONCLUSIONS

We conclude that in patients with an anterolateral AMI, ST-segment depression in lead aVR on admission ECG is useful for predicting larger infarct and left ventricular dysfunction despite successful reperfusion.

Relation of ST-segment changes in inferior leads during anterior wall acute myocardial infarction to length and occlusion site of the left anterior descending coronary artery

We investigated the relation between left anterior descending (LAD) coronary artery morphology and inferior lead ST-segment changes to elucidate the clinical significance of such changes in 159 patients with anterior wall acute myocardial infarction (AMI). Patients with 1-vessel LAD artery lesions were divided into an ST depression group (n = 40), an ST elevation group (n = 25), and a no-ST-change group (n = 94) based on ST-segment changes in the inferior leads. The relation between each group and the infarct-related lesion and the presence of a wrapped LAD artery was then investigated. The percentage of patients with the infarct-related lesion in the proximal LAD artery was significantly higher in the ST depression group and significantly lower in the ST elevation group. The percentage of patients with a wrapped LAD artery was significantly higher in the ST elevation group and significantly lower in the ST depression group. The wall motion index determined echocardiographically was significantly higher in the ST depression group and the no-ST-change group than in the ST elevation group. Our findings suggest that inferior lead ST-segment changes during anterior wall AMI arise as a result of competition between reciprocal changes caused by high lateral wall AMI due to lesions of the proximal LAD artery, which depress the ST segment, and inferoapical wall AMI due to a wrapped LAD artery, which elevates the ST segment. In patients with no ST-segment changes, echocardiography was useful for distinguishing the amount of affected LAD artery territory.