Usefulness of ST elevation II/III ratio and ST deviation in lead I for identifying the culprit artery in inferior wall acute myocardial infarction

Diagnostic value of electrocardiographic indices in discriminating the culprit vessel based on the coronary dominancy in inferior acute myocardial infarction

BACKGROUND

Identifying the culprit during inferior myocardial infarction (MI) is still challenging. We determined the diagnostic effect of electrocardiographic (ECG) indices in identifying the culprit vessel of acute MI and the impact of coronary artery dominance on it.

METHODS

This cross-sectional study included patients with acute inferior MI who presented to Imam Khomeini Hospital and Tehran Heart Center and underwent primary PCI within 12 h of the onset of symptoms. A standard 12‑lead ECG was recorded and interpreted by two cardiologists. Based on the coronary angiography, the patients were divided into two groups of LCX or RCA involvement and were compared for general variables and ECG indices. The diagnostic values of the ECG indices for predicting the culprit vessel were then calculated.

RESULTS

We evaluated 411 patients with inferior STEMI (321 [77.5%] male, age 58.1 ± 11.1 years). RCA was the culprit vessel in 286 patients (69.1%) and LCX in 128 patients (30.9%). 321 patients (77.5%) were right dominant, 40 (9.7%) patients were left dominant, and 53 patients (12.8%), were codominant. Coronary dominance had minimal impact on the ECG indices regarding culprit identification even after adjustment for confounders. STE in lead III > lead II had the highest sensitivity for detecting RCA as the culprit (sensitivity: 89.2% and specificity: 57.8%). STE ≥0.1 mV in V5 or V6 leads had the highest sensitivity for detecting LCX as the culprit (sensitivity: 51.6, specificity: 93.7%).

CONCLUSION

In inferior STEMI, ECG indices can predict the culprit vessel with acceptable sensitivity and specificity independent of coronary artery dominance.

Echocardiographic and Angiographic Assessment of Right Ventricular Function and Right Coronary Artery Stenosis in Acute Inferior Wall Myocardial Infarction

BACKGROUND

Cardiovascular diseases (CVDs) are a global concern. CVD remains a primary cause of death despite reduced coronary heart disease death rates. Acute coronary syndrome (ACS) involves myocardial infarction (MI) and unstable angina, sharing mechanisms such as plaque instability. Our study assesses the right ventricular (RV) function's predictive value in acute inferior wall MI (IWMI) to identify high-risk patients with an elevated likelihood of experiencing severe cardiac complications, hemodynamic instability, or a higher mortality risk following an acute IWMI.

METHODOLOGY

The research was conducted in the Department of Cardiology at the Rajendra Institute of Medical Sciences (RIMS), Ranchi, from July 2021 to June 2022, following the necessary ethical approval. A cohort of 140 patients with IWMI, carefully chosen according to rigorous criteria, clearly understood the study's objectives before providing informed consent. The evaluations were conducted in the following order: clinical assessments, followed by blood testing, then echocardiography, and finally, coronary angiography. Furthermore, the study examined risk factors and utilized statistical methods to elucidate the associations between qualities and results.

RESULTS

The study included 140 participants, with 61% being male and 39% female. Among the participants, 14% were aged 30-45, 50% were aged 46-60, and 30% were over 60. Age shows significant proportions in different categories. Diabetes, dyslipidemia, hypertension, and smoking/tobacco addiction did not differ among stenosis groups. Proximal right coronary artery (RCA) stenosis patients had elevated jugular venous pressure (JVP). The echocardiograms were performed within 48 hours of post-percutaneous coronary intervention, and significant differences between groups were observed. Participants with proximal stenosis had lower tricuspid annular plane systolic excursion (TAPSE) and right ventricular fractional area change (RVFAC), which showed compromised RV systolic function. Proximal stenosis patients had reduced systolic motion velocity (Sm), indicating impaired myocardial contraction. Echocardiographic parameters such as early diastolic velocity (Em), atrial contraction velocity (Am), Em/Am ratio (a marker of diastolic function), isovolumic relaxation time (IVRT), isovolumic contraction time (IVCT), and ejection time (ET) between groups were different, indicating distinct cardiac functions. Proximal stenosis increased the myocardial performance index (MPI), indicating cardiac impairment. The left ventricular ejection fraction (LVEF) was comparable in the two stenosis groups, indicating similar left ventricular performance.

CONCLUSION

 Echocardiography showed significant RV function differences in acute inferior wall ST-segment elevation myocardial infarction (STEMI) patients with proximal and distal RCA lesions. RV dysfunction is linked to right ventricle myocardial infarction (RVMI), and echocardiographic markers can provide valuable insights. Results emphasize that acute inferior wall STEMI is diagnosed by electrocardiogram (ECG) criteria, particularly ST-segment elevation. However, these markers emphasize the importance of RV assessment in RCA involvement assessment. These findings suggest that RV function can help diagnose acute inferior wall STEMI RCA involvement. In acute inferior STEMIs, RV function echocardiography is essential for RCA lesion location.

New ECG algorithms with improved accuracy for prediction of culprit vessel in inferior ST-segment elevation myocardial infarction

BACKGROUND

In addition to diagnosing acute myocardial infarction (MI), the electrocardiogram (ECG) may also predict the culprit coronary artery. We aimed to assess the diagnostic accuracy of ECG algorithms predicting the occluded vessel in inferior ST-segment elevation myocardial infarction (STEMI).

METHODS

This retrospective cohort study included 300 consecutive patients with inferior STEMI undergoing acute coronary angiography. A new method based on the summation of ST-segment deviations in multiple leads from the first 12-lead-ECG was used to develop algorithms to discriminate between right coronary artery (RCA) and circumflex artery (CX) occlusion. Additionally, older algorithms were reassessed.

RESULTS

The RCA was occluded in 235 patients (78%) and the CX in 65 (22%). ST-segment deviations differed significantly between RCA and CX occlusions in leads I, III, aVR, aVL, aVF and V1. ST-segment deviations in lead I showed the highest discriminatory ability of a single lead (area under the receiver operating curve [AUC]=0.77). The summation of multiple leads further increased the discriminatory ability ("III-II+aVF+aVR+V1:" AUC=0.86; "III-II-I+aVF+V1:" AUC=0.85). The best binary algorithm "III-II-I+aVF+V1>0.1 mV" classified 86% of cases correctly and was better than the best old algorithm (83.3%). The simpler algorithm "III+aVR+V1≥0.1 mV" still predicted 85.0% correctly. All algorithms had higher sensitivities for RCA than for CX detection and performed better in right-dominant anatomy.

CONCLUSIONS

A new approach summating multiple ST-segment deviations generated ECG algorithms with higher diagnostic accuracy to predict the occluded vessel in inferior STEMI compared to previous studies. These algorithms may facilitate earlier risk stratification for patients at risk of postinfarct complications.

Localising culprit artery in inferior STEMI

BACKGROUND

ST elevation myocardial infarction (STEMI) represents a cardiac emergency. Time to diagnosis, identification of culprit lesion, and intervention are important. Inferior STEMI represents a dilemma for cardiologists. The territory can be supplied by the right coronary artery (RCA) or the left circumflex coronary artery (LCx). Diagnostic algorithms have been proposed to predict the culprit artery.

METHODS

We performed a single-centre retrospective cohort analysis of all patients admitted to our hospital from 2008 to 2020 with a diagnosis of inferior STEMI. We examined the diagnostic 12 lead ECG for quantification of ST elevation in leads II and III and compared this to culprit lesion found on angiography.

RESULTS

There were 304 patients identified with STEMI in our database; 105 were found to have an inferior myocardial infarction by ECG criteria. Ninety-nine were included in our study with either RCA or LCx culprit lesions on angiography (82 males, 17 females). The average age of these patients was 64.9 years old. Sensitivity, specificity, positive predictive value and negative predictive value for ST elevation in lead II exceeding lead III predicting LCx culprit lesion was 0.32 (95% CI 0.13 to 0.57), 0.94 (95% CI 0.86 to 0.98), 0.55 (95% CI 0.29 to 0.78), 0.85 (95% CI 0.81 to 0.89), respectively. Sensitivity, specificity, positive predictive value and negative predictive value for ST elevation in lead III exceeding lead II predicting RCA culprit lesion was 0.94 (95% CI 0.86 to 0.98), 0.32 (95% CI 0.13 to 0.57), 0.85 (95% CI 0.81 to 0.89), 0.55 (95% CI 0.29 to 0.78), respectively.

CONCLUSIONS

In inferior STEMI, comparison of ST elevation in leads II and III can reliably predict culprit lesion artery and guide intervention.

SUBJECT INDEXING

Culprit artery localisation, inferior stemi, ECG.

A comprehensive and easy-to-use ECG algorithm to predict the coronary occlusion site in ST-segment elevation myocardial infarction

BACKGROUND

Several electrocardiogram (ECG) criteria have been proposed to predict the location of the culprit occlusion in specific subsets of patients presenting with ST-segment elevation myocardial infarction (STEMI). The aim of this study was to develop, through an independent validation of currently available criteria, a comprehensive and easy-to-use ECG algorithm, and to test its diagnostic performance in real-world clinical practice.

METHODS

We analyzed ECG and angiographic data from 419 consecutive STEMI patients submitted to primary percutaneous coronary intervention over a one-year period, dividing the overall population into derivation (314 patients) and validation (105 patients) cohorts. In the derivation cohort, we tested >60 previously published ECG criteria, using the decision-tree analysis to develop the algorithm that would best predict the infarct-related artery (IRA) and its occlusion level. We further assessed the new algorithm diagnostic performance in the validation cohort.

RESULTS

In the derivation cohort, the algorithm correctly predicted the IRA in 88% of cases and both the IRA and its occlusion level (proximal vs mid-distal) in 71% of cases. When applied to the validation cohort, the algorithm resulted in 88% and 67% diagnostic accuracies, respectively. In a real-world comparative test, the algorithm performed significantly better than expert physicians in identifying the site of the culprit occlusion (P = .026 vs best cardiologist and P < .001 vs best emergency medicine doctor).

CONCLUSIONS

Derived from an extensive literature review, this comprehensive and easy-to-use ECG algorithm can accurately predict the IRA and its occlusion level in all-comers STEMI patients.

Identifying the culprit artery via 12-lead electrocardiogram in inferior wall ST-segment elevation myocardial infarction: A meta-analysis

BACKGROUND

Inferior wall ST-segment elevation myocardial infarction (STEMI) is mostly caused by acute occlusion of right coronary artery (RCA) and left circumflex artery (LCX). Several methods and algorithms using 12-lead ECG were developed to localize the lesion in inferior wall STEMI. However, the diagnostic properties of these methods remain under-recognized.

AIMS

The aim of this meta-analysis is to compare the diagnostic properties among the methods of identifying culprit artery in inferior wall STEMI using 12-lead ECG.

METHODS

We performed a meta-analysis to calculate the pooled sensitive, specificity, area under the curve (AUC) and diagnostic odds ratio (DOR) of each method.

RESULTS

Thirty-three studies with 4414 participants were included in the analysis. Methods using double leads had better diagnostic properties, especially ST-segment elevation (STE) in III > II [with pooled sensitivity 0.89 (0.84-0.93), specificity 0.68 (0.57-0.79), DOR 17 (9-32), AUC 0.88 (0.85-0.91)], ST-segment depression (STD) in aVL > I [with pooled sensitivity 0.82 (0.72-0.90), specificity 0.69 (0.48-0.86), DOR 11 (4-29), AUC 0.85 (0.81-0.88)], and STD V3/STE III ≤1.2 [with pooled sensitivity 0.88 (0.78-0.95), specificity 0.59 (0.42-0.75), DOR 12 (5-27), AUC 0.82 (0.78-0.85)]. Diagnostic algorithms, including Jim score[pooled sensitivity 0.70 (0.55-0.85), specificity 0.88 (0.75-0.96)], Fiol's algorithm [pooled sensitivity 0.54 (0.44-0.62), specificity 0.92 (0.88-0.96)] and Tierala's algorithm [pooled sensitivity 0.60 (0.49-0.71), specificity 0.91 (0.86-0.96)], were not superior to these simple methods.

CONCLUSIONS

Our meta-analysis indicated that diagnostic methods using double leads had better properties. STE in III > II together with STD in aVL > I may be the most ideal method, for its accuracy and convenience.

Machine learning of microvolt-level 12-lead electrocardiogram can help distinguish takotsubo syndrome and acute anterior myocardial infarction

Background

Methods

Results

Conclusion

Atypical de Winter ECG pattern may be the mirror image of ST elevation

Background: The de Winter ECG pattern of ST‐segment depression and tall symmetrical T waves, known as an ST elevation equivalent, accounts for approximately 2% of patients with occlusion of the proximal left anterior descending (LAD) coronary artery. The classic de Winter pattern is restricted to cases without ST elevation. However, mixed cases with different types of ST deviation have been described. Here, we describe an interesting case as an example of an ST elevation myocardial infarction (STEMI) equivalent, showing transient transmural ischemia of the inferolateral myocardium, with ECG changes that mimic the de Winter pattern.

Does electrocardiogram help in identifying the culprit artery when angiogram shows both right and circumflex artery disease in inferior myocardial infarction?

OBJECTIVE

In a subgroup of patients with inferior myocardial infarction (MI), both the right coronary artery (RCA) and circumflex coronary artery (Cx) show potentially culprit lesions, and angiography may be insufficient to determine which artery is responsible for the clinical presentation. Although many electrocardiographic (ECG) algorithms have been proposed for identifying the infarct-related artery in patients with inferior MI, it is unclear whether the current algorithms have the discriminative power to identify the real culprit artery in these patients.

METHODS

The patients with the diagnosis of acute inferior MI and underwent coronary angiography were enrolled in the study. The prediction of the infarct-related artery was attempted from the admission ECG using published algorithms and criteria. For the angiographic definition of the infarct-related artery, multiple criteria were used.

RESULTS

Total 417 inferior MI cases were enrolled during the study period; the final patient population comprised of 318 patients. Forty-five patients (14.2%) had both RCA and Cx lesions on coronary angiography. Although several criteria and algorithms are able to identify the infarct-related artery in the general inferior MI population, they lose their strength in patients with both RCA and Cx lesions. Only the Aslanger-Bozbeyoğlu criterion emerges as a more powerful diagnostic test with a sensitivity, specificity, and c-statistic of 80%, 48%, and 0.650, respectively for the whole population (p<0.001) and 81%, 58%, and 0.709, respectively, for patients with both RCA and Cx lesions (p=0.019).

CONCLUSION

The Aslanger-Bozbeyoğlu criterion is not only helpful in differentiating the infarct territory in combined inferior and anterior ST-segment elevation as previously shown, but also valuable in identifying the infarct-related artery in patients with inferior STEMI with critical lesions in both the RCA and the Cx. (Anatol J Cardiol 2020; 23: 318-23).

Electrocardiographic Distinction of Left Circumflexand Right Coronary Artery Occlusion in PatientsWith Inferior Acute Myocardial Infarction

Previously reported electrocardiographic (ECG) criteria to distinguish left circumflex (LCCA) and right coronary artery (RCA) occlusion in patients with acute inferior ST-segment elevation myocardial infarction (STEMI) afford a modest diagnostic accuracy. We aimed to develop a new algorithm overcoming limitations of previous studies. Clinical, ECG, and coronary angiographic data were analyzed in 230 nonselected patients with acute inferior STEMI who underwent primary percutaneous coronary intervention. A decision-tree analysis was used to develop a new ECG algorithm. The diagnostic accuracy of reported ECG criteria was reviewed. LCCA occlusion occurred in 111 cases and RCA in 119. We developed a 3-step algorithm that identified LCCA and RCA occlusion with a sensitivity of 77%, specificity of 86%, accuracy of 82%, and Youden index of 0.63. The area under the ROC curve was 0.85 and resulted 0.82 after a 10-fold cross validation. The key leads for LCCA occlusion were V3 (ST depression in V3/ST elevation in III >1.2) and V6 (ST elevation ≥0.1 mV or greater than III). The key leads for RCA occlusion were I and aVL (ST depression ≥ 0.1 mV). Fifteen of 21 reviewed studies had less than 20 cases of LCCA occlusion, only 48% performed primary percutaneous coronary intervention, and previous infarction or multivessel disease were often excluded. The diagnostic accuracy of reported ECG criteria decreased when applied to our study population. In conclusion, we report a simple and highly discriminative 3-step ECG algorithm to differentiate LCCA and RCA occlusion in an "all comers" population of patients with acute inferior STEMI. The diagnostic key ECG leads were V3 and V6 for LCCA and I and aVL for RCA occlusion.

In inferior myocardial infarction, neither ST elevation in lead V1 nor ST depression in lead I are reliable findings for the diagnosis of right ventricular infarction

OBJECTIVE

In the presence of inferior myocardial infarction (MI), ST depression (STD) in lead I has been claimed to be accurate for diagnosis of right ventricular (RV) MI. We sought to evaluate this claim and also whether ST Elevation (STE) in lead V1 would be helpful, with or without STD in V2.

METHODS

Retrospective study of consecutive inferior STEMI, comparing ECGs of patients with, to those without, RVMI, as determined by angiographic coronary occlusion proximal to the RV marginal branch. STE and STD were measured at the J-point, relative to the PQ junction. The primary outcomes were sensitivity/specificity of 1) STD in lead I ≥ 0.5 mm and 2) STE in lead V1 ≥ 0.5 mm, stratified by presence or absence of posterior (inferobasal) MI, as determined by ≥0.5 mm STD in lead V2, for differentiating RVMI from non-RVMI.

RESULTS

Of 149 patients with inferior STEMI, 43 (29%) had RVMI and 106 (71%) did not. There was no difference in the presence or absence of at least 0.5 mm STD in Lead I between patients with (37/43, 86%) vs. without RVMI (85/106, 80%, p = 0.56). In those with, vs. without, RVMI, (15/43, 35%) had STE in V1, versus (17/106, 16%) (p = 0.015). Specificity of STE in V1 for RVMI was 84%; sensitivity was 35%. Sensitivity was higher without (69%), than with (35%), STD in V2.

CONCLUSION

Among inferior STEMI, the presence of any ST depression in lead I does not help to diagnose RVMI. ST elevation ≥0.5 mm in lead V1 is specific for RVMI, and moderately sensitive only if concomitant STD ≥ 0.5 mm in V2 is not present. Although STE in V1 is quite specific, overall the diagnostic characteristics of the standard 12‑lead ECG are inadequate to definitively diagnose, or exclude, RVMI, as defined angiographically.

Electrocardiogram criteria of limb leads predicting right coronary artery as culprit artery in inferior wall myocardial infarction: A meta-analysis

BACKGROUND

Prior studies have proposed several electrocardiogram (ECG) criteria in limb leads for identifying the culprit coronary artery (CCA) in patients with acute inferior wall myocardial infarction (IWMI). The aim of our study was to conduct an evidence-based evaluation and test accuracy comparison of these criteria.

METHODS

We searched the PubMed, Embase, and Ovid. Eligible studies to assess the diagnostic performance of ECG criteria predicting CCA in IWMI were reviewed for inclusion. A diagnostic meta-analysis of bivariate approach was performed for pooled estimates of sensitivity and specificity, and meta-regression was implemented to investigate sources of heterogeneity.

RESULTS

Twenty-four studies with 4431 unique participants met the inclusion criteria. The pooled sensitivity and specificity for ST-segment elevation (STE) in III > II, ST-segment depression (STD) in I, STD in aVL, STD in aVL > I, STE in III > II, and STD in aVL > I were 0.91 (0.88-0.94) and 0.69 (0.53-0.81), 0.80 (0.73-0.87) and 0.69 (0.62-0.76), 0.90 (0.81-0.95) and 0.41 (0.22-0.62), 0.84 (0.75-0.91) and 0.72 (0.48-0.88), and 0.79 (0.62-0.90) and 1.00 (0.37-1.00), respectively. Heterogeneity investigation showed that whether multi-vessel diseased patients were excluded, sample size, publication year, etc., could influence the diagnostic performance.

CONCLUSION

STE in III > II performed better than other criteria for predicting RCA as CCA in IWMI, and STE in III > II and STD in aVL > I were potential and simple algorithms. ECG could be an effective tool to identify the CCA, but future studies are clearly needed to address the potential of diagnostic and prognostic value.

Reconstruction of 12-lead ECG Using a Single-patch Device

Objectives: The aim of this study is to develop an optimal electrode system in the form of a small and wearable single-patch ECG monitoring device that allows for the faithful reconstruction of the standard 12-lead ECG.

Methods: The optimized universal electrode positions on the chest and the personalized transformation matrix were determined using linear regression as well as artificial neural networks (ANNs). A total of 24 combinations of 4 neighboring electrodes on 35 channels were evaluated on 19 subjects. Moreover, we analyzed combinations of three electrodes within the four-electrode combination with the best performance.

Results: The mean correlation coefficients were all higher than 0.95 in the case of the ANN method for the combinations of four neighboring electrodes. The reconstructions obtained using the three and four sensing electrodes showed no significant differences. The reconstructed 12-lead ECG obtained using the ANN method is better than that using the MLR method. Therefore, three sensing electrodes and one ground electrode (forming a square) placed below the clavicle on the left were determined to be suitable for ensuring good reconstruction performance.

Conclusions: Since the interelectrode distance was determined to be 5 cm, the suggested approach can be implemented in a single-patch device, which should allow for the continuous monitoring of the standard 12-lead ECG without requiring limb contact, both in daily life and in clinical practice.

Electrocardiogram in patients with acute inferior myocardial infarction due to occlusion of circumflex artery

To investigate the diagnostic value of electrocardiographic (ECG) ST-segment in acute inferior myocardial infarction (AIMI) caused by the left circumflex branch (LCX).A total of 240 clinical cases with AIMI in our hospital were retrospectively analyzed. All of them had received percutaneous coronary intervention (PCI) within 12 hours after symptom onset. The clinical features, ECG manifestations, and coronary artery lesion characteristics of the patients were collected.The right coronary artery (RCA) was shown to be the infarct-related artery (IRA) in 177 patients, while LCX was responsible for AIMI in 63 cases. There was no significant difference in the risk factors of coronary heart disease (CHD) (P > .05 for all) between the 2 groups. ST-segment elevation in lead II, III, and AVF could be found in all patients. Moreover, ST-segment depression in lead I (STD I), ST-segment elevation in lead III (STE III), STE III-STE II, STE AVF, STD AVL, STD AVL-STD I and STE v6 lead ST-segment deviation exhibited significant difference in 2 groups (P < .05 for all). The changes of STD I, STE III < STEII, STD AVL < STD I could discriminate between LCX and RCA in AIMI patients with high sensitivity and specificity.ECG may be an effective tool to predict the IRA in patient with AIMI.

15th Sukaman Memorial Lecture

Of all the non-arrhythmic electrocardiographic (ECG) abnormalities, ST segment elevation (ST elevation) is the most important with regard to diagnosis, prognosis and management.

Right ventricular echocardiographic parameters for prediction of proximal right coronary artery lesion in patients with inferior wall myocardial infarction

Background

Classifying the location of an occlusion in the culprit artery during ST-elevation myocardial infarction is important for risk stratification to optimize treatment.

Objectives

To compare the validity of echocardiographic parameters assessing right ventricular (RV) function for the prediction of proximal right coronary artery (RCA) lesion in patients with inferior wall myocardial infarction.

Methods

The study included 76 patients after their first episode of acute inferior myocardial infarction with significant RCA lesion (43 patients with proximal RCA stenosis and 33 patients with distal RCA stenosis). Full echocardiographic examination was done before revascularization, including RV dimension, tricuspid annular plane systolic excursion, and tissue Doppler imaging of RV free wall at the level of the tricuspid annulus and recording the following variables: peak systolic velocity (Sm), peak early diastolic velocity, peak late diastolic velocity, ejection time (ET), isovolumetric relaxation time (IVRT), isovolumetric contraction time (IVCT), and myocardial performance index (MPI), which was calculated as (MPI = IVRT + IVCT/ET).

Results

Patients with proximal RCA showed significantly lower Sm (10.44 ± 2.61 cm/s vs. 12.11 ± 2.94 cm/s, p = 0.013) and shorter ET (224.18 ± 49.96 ms vs. 280.90 ± 46.12 ms, p = 0.001). While IVRT, IVCT, and MPI were significantly higher (95.25 ± 19.22 ms vs. 68.48 ± 12.77 ms, p = 0.001; 81.62 ± 23.59 ms vs. 60.90 ± 17.38 ms, p = 0.001; and 0.82 ± 0.222 vs. 0.47 ± 0.10, p = 0.001, respectively) when compared with patients with distal RCA stenosis. Multiple regression analysis including (tricuspid annular plane systolic excursion, Sm, and MPI) showed that the most independent predictors for proximal RCA lesions were MPI (p = 0.0001). The receiver operator characteristic curve for MPI showed areas under the curve of 97% and a confidence interval of 93%. A cut-off value of 0.58 for MPI had a sensitivity of 95% and specificity of 97% for the diagnosis proximal RCA.

Conclusions

The most independent predictors for proximal RCA lesion is MPI.

The Value of Lead aVR ST Segment Changes in Localizing Culprit Lesion in Acute Inferior Myocardial Infarction and Its Prognostic Impact

BACKGROUND

Identifying infarct-related artery (IRA) in patients with inferior ST elevation myocardial infarction (STEMI) has prognostic and therapeutic benefits.

OBJECTIVES

To differentiate IRA and the location of culprit lesion in inferior STEMI, using ST segment changes in lead aVR.

METHODS

ST segment changes in lead aVR were recorded in 150 patients, admitted with first inferior STEMI. The association of IRA and the location of culprit lesion with ST segment changes in aVR were investigated.

RESULTS

ST elevation ≥ 0.5 mm in lead aVR was present in 17 patients (11.3%), ST depression ≥ 0.5 mm in 74 patients (49.3%) and 59 patients (39.3%) did not have significant ST segment changes. Right coronary artery (RCA) was the IRA in 117 patients (78%) and left circumflex artery (LCX) in 33 patients (22%). Prevalence of RCA involvement as the IRA was different in three study groups (94.1% in ST elevation group, 83.1% in isoelectric group and 70.3% in ST depression group, P = 0.049). Presence of ST elevation had a sensitivity and specificity of 13.68 % and 96.97%, for detecting RCA lesions, respectively. ST depression had 66.67% sensitivity and 55.56% specificity for identifying LCX lesions. Clinical complications were low in our study with no significant difference among patients of three groups.

CONCLUSIONS

Presence of ST elevation is highly suggestive of RCA lesions versus LCX lesions, whereas absence of ST elevation cannot rule out RCA lesions. Presence of ST depression has a moderate sensitivity and specificity for LCX lesions.

Jeopardised Inferior Myocardium (JIM) Score: An Arithmetic Electrocardiographic Score to Predict the Infarct-Related Artery in Inferior Myocardial Infarction

Introduction: A few electrocardiographic criteria have been described to identify the infarct-related artery in inferior myocardial infarction. The aim of this study was to devise an arithmetic score to further improve the diagnostic accuracy. Materials and Methods: From 2004 to 2006, 78 patients who underwent primary angioplasty for inferior myocardial infarction within 6 hours from symptom onset were recruited for electrocardiographic and angiographic analysis. Results: The mean age of patients was 65 ± 12 years with male predominance (74%). Less ST depression in lead I and aVL, and more prominent ST depression in lead V1-3 were observed in left circumflex artery (LCX) than right coronary artery (RCA) occlusions. In addition, more prominent ST depression in lead I and ST elevation in V1 were found in proximal RCA than distal RCA occlusions. Based on the findings, the Jeopardised Inferior Myocardium (JIM) score was constructed and defined as [II–V3/III+V1– I]. The sensitivity and specificity of JIM score ≤0.5 to predict proximal RCA occlusions; 0.5 <JIM score ≤1.5 to predict distal RCA occlusions; and JIM score >1.5 to predict LCX occlusions were 58% and 85%, 69% and 68%, and 79% and 94%, respectively. The accuracy of prediction is slightly better than the 2 previously reported criteria. Conclusion: By taking into account more leads, the JIM score is capable of identifying the infarct-related artery with an improved diagnostic accuracy. Key words: Coronary angiography, Electrocardiography

Implications of ST-segment elevation in leads V5 and V6 in patients with reperfused inferior wall acute myocardial infarction

During inferior acute myocardial infarction, ST-segment elevation (ST↑) often occurs in leads V(5) to V(6), but its clinical implications remain unclear. We examined the admission electrocardiograms from 357 patients with a first inferior acute myocardial infarction who had Thrombolysis In Myocardial Infarction 3 flow of the right coronary artery or left circumflex artery within 6 hours after symptom onset. The patients were divided according to the presence (n = 76) or absence (n = 281) of ST↑ >2 mm in leads V(5) and V(6). Patients with ST↑ in leads V(5) and V(6) were subdivided into 2 groups according to the degree of ST↑ in leads III and V(6): ST↑ in lead III greater than in V(6) (n = 53) and ST↑ in lead III equal to or less than in V(6) (n = 23). The perfusion territory of the culprit artery was assessed using the angiographic distribution score, and a mega-artery was defined as a score of ≥0.7. ST↑ in leads V(5) and V(6) with ST↑ in lead III greater than in V(6) and ST↑ in leads V(5) and V(6) with ST↑ in lead III equal to or less than in V(6) were associated with mega-artery occlusion and impaired myocardial reperfusion, as defined by myocardial blush grade 0 to 1. Right coronary artery occlusion was most common (96%) in the former, and left circumflex artery occlusion was most common (96%) in the latter, especially proximal left circumflex occlusion (74%). Multivariate analysis showed that ST↑ in leads V(5) and V(6) with ST↑ in lead III greater than that in V(6) (odds ratio 4.81, p <0.001) and ST↑ in leads V(5) and V(6) with ST↑ in lead III equal or less than that in V(6) (odds ratio 5.96, p <0.001) were independent predictors of impaired myocardial reperfusion. In conclusion, ST↑ in leads V(5) and V(6) suggests a greater risk area and impaired myocardial reperfusion in patients with inferior acute myocardial infarction. Furthermore, comparing the degree of ST↑ in lead V(6) with that in lead III is useful for predicting the culprit artery.

ST-segment depression in aVR as a predictor of culprit artery and infarct size in acute inferior wall ST-segment elevation myocardial infarction

BACKGROUND

ST-segment depression in lead aVR in acute inferior wall ST-segment elevation myocardial infarction (STEMI) has recently been suggested as a predictor of left circumflex (LCx) artery involvement. The purpose of this study is to evaluate the clinical significance of aVR depression during inferior wall STEMI.

METHODS

This study included 106 consecutive patients who presented with inferior wall STEMI and underwent urgent coronary angiogram. Clinical and angiographic findings were compared between patients with and without aVR depression > or = 0.1 mV.

RESULTS

The sensitivity and specificity of aVR depression as a predictor of LCx infarction were 53% and 86%, respectively. In patients with right coronary artery infarction, aVR depression was associated with increased cardiac enzymes and the involvement of a large posterolateral branch, which may explain the larger infarction.

CONCLUSIONS

ST-segment depression in lead aVR in inferior wall STEMI predicts LCx infarction or larger RCA infarction involving a large posterolateral branch.

Utility of lead aVR for identifying the culprit lesion in acute myocardial infarction

BACKGROUND

Lead aVR is a neglected, however, potentially useful tool in electrocardiography. Our aim was to evaluate its value in clinical practice, by reviewing existing literature regarding its utility for identifying the culprit lesion in acute myocardial infarction (AMI).

METHODS

Based on a systematic search strategy, 16 studies were assessed with the intent to pool data; diagnostic test rates were calculated as key results.

RESULTS

Five studies investigated if ST-segment elevation (STE) in aVR is valuable for the diagnosis of left main stem stenosis (LMS) in non-ST-segment AMI (NSTEMI). The studies were too heterogeneous to pool, but the individual studies all showed that STE in aVR has a high negative predictive value (NPV) for LMS. Six studies evaluated if STE in aVR is valuable for distinguishing proximal from distal lesions in the left anterior descending artery (LAD) in anterior ST-segment elevation AMI (STEMI). Pooled data showed a sensitivity of 47%, a specificity of 96%, a positive predicative value (PPV) of 91% and a NPV of 69%. Five studies examined if ST-segment depression (STD) in lead aVR is valuable for discerning lesions in the circumflex artery from those in the right coronary artery in inferior STEMI. Pooled data showed a sensitivity of 37%, a specificity of 86%, a PPV of 42%, and an NPV of 83%.

CONCLUSION

The absence of aVR STE appears to exclude LMS as the underlying cause in NSTEMI; in the context of anterior STEMI, its presence indicates a culprit lesion in the proximal segment of LAD.

A new ECG criterion to identify takotsubo cardiomyopathy from anterior myocardial infarction: role of inferior leads

With the exception of contrast-enhanced cardiovascular magnetic resonance imaging, clear distinction of takotsubo cardiomyopathy from anterior wall myocardial infarction cannot be achieved currently by simple and noninvasive tests. The aim of this study was to examine the role of inferior ECG leads in distinguishing these two conditions. From January 2004 to June 2006, eight female patients suffering from takotsubo cardiomyopathy were identified by the Mayo Clinic criteria. The clinical and ECG features were compared with 27 consecutive sex- and age-matched patients with anterior wall myocardial infarction admitted to the Coronary Care Unit within the same period. The observed ECG features were then verified with that of 62 published cases of takotsubo cardiomyopathy. Takotsubo cardiomyopathy patients had similar left ventricular ejection fraction (35.0% +/- 5.7% vs 38.2% +/- 6.4%, P = 0.829), lower peak creatinine kinase level (461 +/- 330 U/l vs 2723 +/- 1826 U/l, P = 0.020), more ST-segment elevation in the inferior leads (50% vs 7.4%, P = 0.016), and virtually no ST-segment depression in inferior leads (0% vs 48.2%, P = 0.015) compared with patients who had anterior wall myocardial infarction. ST-segment elevation of >or=1.0 mm in lead II had 62.5% sensitivity and 92.6% specificity in detecting takotsubo cardiomyopathy. The observed ECG characteristics were comparable with those in the literature. In patients who present with anterior wall myocardial infarction, the absence of ST-segment depression or ST-segment elevation in inferior leads, especially if the ST-segment in lead II >or= III, is highly suggestive of takotsubo cardiomyopathy.

Predicting the culprit artery in acute ST-elevation myocardial infarction and introducing a new algorithm to predict infarct-related artery in inferior ST-elevation myocardial infarction: correlation with coronary anatomy in the HAAMU Trial

AIMS

The objective of this study is to predict the culprit artery from the electrocardiogram (ECG) by predefined criteria and to compare a new algorithm with a previous one for predicting the culprit artery in inferior ST-elevation myocardial infarction (STEMI).

METHODS AND RESULTS

In "all-comers" (n = 187) with acute STEMI, with ECG and angiography from the acute phase, the positive and negative predictive values for the prediction of the left anterior descending coronary artery, left circumflex coronary artery, or right coronary artery as the infarct-related artery were 96% and 96%, 65% and 95%, 92% and 97%, respectively. In inferior STEMI (n = 98), positive and negative predictive values to predict the right coronary artery or the left circumflex coronary artery as the culprit artery were 92% and 75% and 75% and 94%, respectively.

CONCLUSIONS

In "all-comers" with STEMI, the culprit artery could be predicted by ECG criteria with high predictive values. In inferior STEMI, a new algorithm for culprit artery prediction was successfully tested.

Electrocardiographic characteristics of patients with inferior myocardial infarction but angiographically normal coronary arteries

Normal coronary arteries were found in 22 (5.8%) of 379 patients presented with acute inferior myocardial infarction. These patients were significantly younger, had less cardiovascular risk factors, better systolic heart function, and lower cardiac enzymes level. Electrocardiography significantly showed more (1) ratio of ST-segment elevation in II/ III>or=1; (2) isoelectric ST-segment in I; (3) ST-segment elevation in I; and less (4) paroxysmal atrial fibrillation; (5) ST-segment depression in I; and (6) ST-segment elevation in V4R. In conclusion, this subset of patients had clinical features suggestive of smaller infarct size compared with those suffering from atherosclerotic disease. They may have more left circumflex artery involvement and distal right coronary artery occlusion, as deduced from electrocardiography.

Value of ST-segment depression in lead V4R in predicting proximal against distal left circumflex artery occlusion in acute inferoposterior myocardial infarction

BACKGROUND

Lead V(4R) faces the right ventricular free wall; it also reflects ischemia in the posterolateral wall lying opposite and manifests as ST-segment depression.

HYPOTHESIS

The aim of this study was to evaluate the usefulness of V(4R) ST-segment depression in distinguishing proximal from distal left circumflex artery occlusion in acute inferoposterior wall myocardial infarction.

METHODS

We retrospectively analyzed 239 patients who had first acute inferoposterior myocardial infarction, were admitted within 6 h from onset of symptom, and had coronary angiography performed within 4 weeks. Patients who had bundle-branch block or concomitant significant stenoses in the proximal and distal segments of the same vessel or of both vessels were excluded. The electrocardiographic and angiographic findings were reviewed by two independent groups of investigators.

RESULTS

V(4R) ST-segment depression > or =1.0 mm was found in 8 of 46 patients (17.4%) with left circumflex artery occlusion but none (0%) with right coronary artery occlusion. Among the group with left circumflex artery occlusion, the mean magnitude of V(4R) ST-segment depression was greater in proximal than distal occlusion (0.82 +/- 0.65 vs. 0.03 +/- 0.12 mm, p < 0.0001). V(4R)ST-segment depression > or =1.0 mm was found in 8 of 14 patients (57.1%) with proximal occlusion but none (0%) in 32 patients with distal occlusion. The sensitivity and specificity to predict proximal occlusion were 57.1 and 100%, respectively.

CONCLUSIONS

V(4R) ST-segment depression > or =1.0 mm was not useful for differentiating left circumflex and right coronary artery occlusion because of its low sensitivity. It is a fairly sensitive and very specific sign of proximal left circumflex artery occlusion.

Electrocardiographic features and prognosis in acute diagonal or marginal branch occlusion

The aim of our study was to analyze electrocadiographic changes in patients with acute myocardial infarction related to the occlusion of diagonal (DG) or marginal (MG) branch. We selected 13 cases with DG and 12 with MG occlusion on angiography and evaluated their electrocardiogram (ECG) patterns on admission obtained in emergency department (ED) of university hospital with catheterization laboratory serving everyday interventional cardiology duty for ACS. Most characteristic ECG changes in acute occlusion of DG observed in 12 patients (92.3%) included ST-segment elevation in leads V(2) and V(3) (mean, 1.2 +/- 0.5 mm; maximum, 1.7 mm) and ST-segment depression in leads II and III (mean, 0.9 +/- 0.4 mm; maximum, 1.5 mm). Most characteristic ECG changes for acute occlusion of MG were ST-segment depression in leads V(5) and V(6) (mean, 0.9 +/- 0.4 mm; maximal, 1 mm) observed in 11 (91.7%) patients, ST-segment depression in lead II (mean, 0.7 +/- 0.2 mm; maximal, 0.8 mm) in 10 (83.3%,) and in leads V(2) and V(3), and aVF in 8 (66.7%) of cases. Risk of complications including cardiogenic shock and death was high in both groups especially during acute phase of myocardial infarction. Prevalence of borderline ECG changes in patients with acute coronary occlusion confirms how important is precise ECG interpretation usually initially done by ED physician.

The value of ECG lead aVR in the differential diagnosis of acute inferior wall myocardial infarction

OBJECTIVES

To investigate whether the ST changes in the aVR lead on 12-lead ECG can be used to identify infarct-related artery (IRA) in patients with acute inferior myocardial infarction.

METHODS

The ECG features were studied in 90 patients with acute inferior myocardial infarction where IRA was confirmed by coronary angiography.

RESULTS

Right coronary artery (RCA) and the left circumflex coronary artery (LCX) were identified as IRA in 70 and 20 patients, respectively. ST depression in aVR > or = 0.1 mV was found in 14 (70%) patients who had LCX as the IRA, and in 4 (5.7%, p<0.001) patients with RCA as IRA. Using ST segment depression > or = 0.1 mV in aVR as a criterion, the sensitivity and specificity in differentiating LCX as IRA was 70.0% and 94.3%, respectively.

CONCLUSIONS

ST depression in aVR is common in patients with LCX-related acute inferior myocardial infarction. The ST changes in this lead are associated with an excellent specificity and a good sensitivity in differentiating LCX from RCA as the IRA.

Precordial ST-segment elevation in acute occlusion of the proximal right coronary artery

Isolated right ventricular myocardial infarction (RVMI) rarely occurs and accounts for only 3% of all myocardial infarction cases. In the literature, there are several reported isolated RVMI cases with precordial ST-segment elevation. We describe a 45-year-old man with marked ST-segment elevations in leads V1 through V4 accompanied by slight ST-segment elevations in the inferior leads (III, aVF) caused by acute occlusion of a nondominant small right coronary artery proximal to the conus branch causing isolated RVMI.

Acute coronary syndromes

Despite technologic advances in many diagnostic fields, the 12-lead ECG remains the basis for early identification and management of an acute coronary syndrome. This article reviews the use of the ECG in acute coronary syndromes.

New criteria based on ST changes in 12-lead surface ECG to detect proximal versus distal right coronary artery occlusion in a case of acute inferoposterior myocardial infarction

BACKGROUND

The outcome of patients with inferoposterior myocardial infarction (MI) due to occlusion of right coronary artery (RCA) depends mainly on the location of occlusion (distal vs. proximal). The aim of this study was to evaluate the value of new ECG criteria: the sum of ST depression in I and VL leads and ST changes in V1 lead to predict the location of RCA occlusion in the case of an inferoposterior MI.

METHODS

The ECG and angiographical findings of 50 patients with acute inferoposterior MI due to RCA occlusion were analyzed. The value of new criteria was studied alone and in combination to predict proximal versus distal RCA occlusion and compared with previously described criterion based only on ST changes in VL.

RESULTS

Isoelectric or elevated ST in V1 allowed predicting proximal RCA occlusion with 70% sensitivity and 87% specificity with high positive and negative predictive value (87% and 71%, respectively). The new criterion of the sum of ST depression in I and VL >or= 5.5 mm compared to the criterion based only on ST depression in VL was also more specific (91% vs. 72%) for proximal RCA occlusion with better positive and negative predictive values.

CONCLUSIONS

The new criterion based on the ST changes in V1 lead is highly accurate in detecting the location of occlusion in the RCA compared to the criteria based only on ST changes in lateral leads. The use of this criterion might increase the accuracy of ECG-based identification of myocardial involvement in acute inferoposterior MI.

Absence of ST elevation in ECG leads V7, V8, V9 in ischaemia of non-occlusive aetiologies

BACKGROUND AND OBJECTIVE

Occlusion of the circumflex coronary artery may present with either ST elevation typical of inferior or lateral myocardial infarction, ST depression or a normal 12-lead electrocardiogram (ECG). In patients presenting with ST depression, concomitant ST elevation in the posterior leads V7, V8 and V9 is believed to reflect ST-elevation myocardial infarction of the posterior wall. However, to be confident of this diagnosis, it is necessary to know that posterior ST depression does not occur in acute subendocardial ischaemia.

METHODS AND RESULTS

We have prospectively recorded leads V7, V8 and V9 simultaneously with the standard 12-lead ECG in patients who underwent treadmill stress test. Group A consists of 35 patients who showed ischaemic praecordial ST depression in their 12-lead ECGs during treadmill stress test and subsequent angiographic documentation of significant coronary artery disease. Group B consists of 35 subjects who showed normal ECG findings during treadmill stress test. In none of the Group A or B patients was there ST elevation in leads V7, V8 or V9 either at rest or at peak exercise. ST depression was seen in 69% in V7, 31% in V8 and 11% in V9 in the Group A patients at peak exercise.

CONCLUSION

ST elevation in leads V7, V8 and V9 is uncommon in patients presenting with subendocardial ischaemia. Therefore, in patients presenting with acute chest pain and ST depression in the 12-lead ECG, concomitant posterior ST elevation may be a reliable indicator of ST elevation posterior MI. This is likely due to circumflex artery occlusion and may require thrombolytic therapy.

Prediction of infarct-related coronary artery of patients with acute inferior myocardial infarction by a predischarge exercise test index

The predictive accuracy of electrocardiographic markers in identifying the infarct-related artery of myocardial infarctions has been a subject of extensive investigation. The present study was designed to test whether the index L II/L III ratio adapted to exercise electrocardiograms could be utilized as a marker to distinguish right coronary and left circumflex arteries as culprit coronaries in acute inferior myocardial infarctions. For this purpose, 82 patients with a positive-symptom-limited and/or submaximal treadmill exercise test with modified Bruce protocol after an acute inferior myocardial infarction were studied. Those patients with ST segment elevation during the stress test were included in the study. ST segment index was defined as the ratio of exercise-induced ST elevation amplitude in L II/L III. Patients were classified as having an index > 1 (n=24) and < 1 (n=58), and the findings were compared with the findings on coronary angiography. The groups were comparable with respect to age, gender, peak exercise level, and double products achieved. Circumflex artery was the infarct-related one in the majority (21/24; 88%) of patients with an index > 1, whereas most (51/58; 88%) patients with an index < 1 had the culprit lesion in their right coronary artery (p<0.001). The ratio of exercise-induced ST elevations in leads L II and L III has a significantly high ability to discriminate the infarct-related coronary artery in patients with uncomplicated inferior myocardial infarction. Considering the prognostic importance of the type of coronary involvement, this index could be a part of predischarge evaluation in this patient group.

New electrocardiographic criteria for identifying the culprit artery in inferior wall acute myocardial infarction-usefulness of T-wave amplitude ratio in leads II/III and T-wave polarity in the right V5 lead

ST-segment elevations in the right ventricular lead and those greater in lead III than in lead II strongly suggest that right, rather than left circumflex, coronary arterial occlusion occurs in acute myocardial infarction in the inferior wall. Our study demonstrated that, in the very early stages of infarction, a T-wave amplitude that is greater in lead III than in lead II and an upright or positive biphasic T wave in lead V(5)R are just as predictive as ST-segment changes and are often easier to measure.

How to use ECG for decision support in the catheterization laboratory

Treatment of acute myocardial infarction has changed considerably during the last few years with the introduction of primary coronary angioplasty. In the acute phase risk stratification is largely based on simple clinical parameters, laboratory markers of myocardial injury and 12-lead electrocardiography. The electrocardiogram is of crucial importance especially during the first few hours after initiation of chest pain when important therapeutic decisions are made. Biochemical markers of myocardial injury are usually not elevated at that time point. Cases with inferior ST-elevation myocardial infarction from our hospital are presented to show how anatomical interpretation of ECG recorded during chest pain helps to risk stratify patients.

Prehospital 80-LAD mapping: Does it add significantly to the diagnosis of acute coronary syndromes?

Early detection of acute myocardial infarction (MI) is vital in the management of acute coronary syndromes (ACS). Hence we compared the diagnostic capability of the standard 12-lead electrocardiogram (ECG) with the 80-lead ECG body surface map (BSM) prehospital.

METHODS

Consecutive patients (n = 294) presenting prehospital with ischemic type chest pain were included. All had an ECG and BSM pretreatment and a baseline and 12-hour cardiac troponin-T or I (cTnT or cTnI). Acute MI was defined as cTnT > 0.09 or cTnI > 0.1 ng/mL. Acute MI on the BSM was defined as ST elevation measured at the J-point, > or = 1 mm inferior/right ventricular/high right anterior/lateral regions, > or = 2 mm anterior region, > or = 0.5 mm posterior region.

RESULTS

Acute MI occurred in 182/294 (62%) based on cTnT or I. ST elevation on the standard ECG predicted acute MI in 103 (sensitivity 57%, specificity 94%; c-statistic 0.73). The optimal model for the standard ECG included ST elevation, summed ST depression and past history of MI (c-statistic 0.82; Chi-square (Wald) 120.7, 3df). The BSM predicted acute MI in 146 (sensitivity 80%, specificity 92%; c-statistic 0.86). The optimal model for the BSM included BSM criteria for acute MI and past history of MI (c-statistic 0.91; Chi-square (Wald) 180.3, 2df).

CONCLUSION

The 80-lead BSM is superior to the standard 12-lead ECG in predicting acute MI prehospital.