Electrocardiographic identification of the infarct-related artery in acute inferior myocardial infarction.

INTRODUCTION: Mortality and morbidity from acute inferior myocardial infarction (MI) are determined, among other factors, by the infarct-related artery (IRA). Several electrocardiographic (ECG) criteria have been proposed to differentiate between the right coronary artery (RCA) and the left circumflex coronary artery (LCx) as the IRA in inferior MI. Recently, a new criterion has been proposed (ST segment depression in lead aVR). It was our objective to evaluate the old and the new ECG criteria in identifying the IRA in patients with inferior MI. METHODS: Patients with inferior MI treated by primary angioplasty were included, following evaluation of the admission ECG. Patients with a previous history of Q-wave myocardial infarction and complete bundle branch block were excluded. The artery with the most severe lesion was considered the IRA. The following ECG criteria were assessed: ST depression in lead DI; ST depression in leads V1 and V2, ST elevation in lead DIII > DII, ST depression in V3/ST elevation in DIII ratio > 1.2 (classical criteria) and ST depression in lead aVR. ST-segment elevation or depression was measured 0.06 sec after the J point. RESULTS: 53 patients were included (mean age 59.1 +/- 13.9 years, 38 males). The RCA was the IRA in 38 patients and the LCx in 15. Baseline characteristics (age, gender, TIMI flow, Killip class, and pain-to-balloon time) were similar in both groups. All the classical criteria were able to identify the IRA. The new criterion--ST depression in lead aVR--identified the IRA in a small number of patients (sensitivity 33%, specificity 71%, p = NS). CONCLUSIONS: The 4 classical criteria were useful in identifying the IRA in patients with inferior MI. ST depression in lead aVR (a recently proposed new criterion), on the other hand, showed limited utility in differentiating between RCA and LCx.     

体表心电图预测下壁心肌梗塞的梗塞相关动脉

目的 探讨下壁急性心肌梗塞的初始心电图能否预测梗塞相关动脉(IRA)以及合并存在的冠状动脉病变是否会改变这种预测能力.方法 102例下壁AMI病人在入院时记录标准十二导联心电图的ST段移位情况,并在住院期间行冠状动脉造影确定IRA,分析心电图ST移位与梗塞相关动脉的关系.结果(1)双左回旋支(LCX)为IRA的病人和以右冠状动脉(RC)为IRA的病人相比,前者V_1或V_2导联ST段压低的发生率明显高于后者(分别为80%和43%,P<0.01),前者I导联ST段抬高或位于等电位线的发生率也高于后者(分别为63%和27%,P<0.05);(2)根据V_1或V_2导联ST段压低判断LCX为IRA的敏感性、特异性和阴性预测值分别为83%、56%和93%.结论 下壁AMI时V_1或V_2导联ST段压低是判断LCX作为IRA敏感指标,并具有很高的阴性预测值,合并存在的冠状动脉病变不会改变这种预测能力.     

Correlation between index electrocardiographic patterns and pre‐intervention angiographic findings: Insights from the HORIZONS‐AMI trial

Objectives : To improve ECG interpretation accuracy in patients with chest pain prior to activation of the cardiac catheterization laboratory for primary percutaneous coronary intervention (PPCI). Background : Despite current guideline‐based ECG criteria, challenges remain in optimizing the rate of appropriate catheterization laboratory activation. Methods : The HORIZONS‐AMI trial enrolled 3,602 patients with chest pain consistent with myocardial infarction (MI). ECG and angiographic core laboratory databases were analyzed for correlation between the qualifying study ECG and the baseline coronary angiogram. Results : LAD occlusion manifested in >80% of cases as ST‐segment elevation in leads V2 and V3, while the culprit vessel was the RCA and LCx in 75 and 25% of cases, respectively, for inferior MI ECG patterns. The study threshold of ≥1.0 mm ST‐segment elevation in ≥2 contiguous ECG leads was not met in 189 (5.3%) patients. When stratified by culprit artery, the prevalence of reciprocal ST‐segment depression ranged from 24 to 88%, being least common for lesions in the mid‐ and distal left anterior descending artery. Despite study eligibility, no posterior MIs were enrolled. Only 36 LBBB cases were identified (25% of whom did not undergo PCI), and 5 of 11 left main coronary occlusions (45%) had ST‐segment elevation in lead aVR. Conclusions : The present study confirms prior ischemic ECG findings predicted by vectorcardiography, validates certain ECG patterns as reliable surrogate markers for acute coronary occlusion, and provides novel insights correlating index ECG ischemic changes and pre‐intervention coronary angiography. These results may enhance the rate of appropriate catheterization laboratory activation. © 2011 Wiley Periodicals, Inc.     

ST-segment depression in lead aVR: a useful predictor of impaired myocardial reperfusion in patients with inferior acute myocardial infarction

STUDY OBJECTIVE: During inferior acute myocardial infarction (AMI), the ECG lead aVR is frequently ignored, and therefore its clinical significance remains unclear. We examined the relation between ST-segment deviation seen in lead aVR on ECGs obtained at hospital admission and myocardial reperfusion in patients who have experienced recanalized inferior AMIs. DESIGN AND SETTING: Retrospective study. PATIENTS: A total of 225 patients with inferior AMIs in whom Thrombolysis in Myocardial Infarction grade 3 flow was achieved within 6 h after symptom onset. MEASUREMENTS AND RESULTS: Patients were classified as follows according to ST-segment deviation in lead aVR on an ECG obtained at hospital admission: group A, 103 patients with no ST-segment depression; group B, 80 patients with ST-segment depression of < or = 1.0 mm; and group C, 42 patients with ST-segment depression of > 1.0 mm. There were no differences in time from symptom onset to hospital admission or in the culprit lesion among the three groups. The degree of ST-segment elevation in leads II, III, aVF, V5, or V6, the degree of ST-segment depression in leads V1 to V4, and the sum of ST-segment deviation in these leads were lowest in group A and highest in group C. In groups A, B, and C, the incidence of impaired myocardial reperfusion, defined as myocardial blush grade 0/1, was 2%, 23%, and 67%, respectively (p < 0.001). The sensitivity and negative predictive values of ST-segment depression in lead aVR for impaired myocardial reperfusion were higher than those based on other ECG variables. Multivariate analysis showed that the degree of ST-segment depression in lead aVR was an independent predictor of impaired myocardial reperfusion (odds ratio 8.41; 95% confidence interval, 2.96 to 23.9; p < 0.001). CONCLUSIONS: We conclude that the degree of ST-segment depression in lead aVR is a useful predictor of impaired myocardial reperfusion in patients who have experienced inferior AMIs.     

Clinical utility of ST-segment depression in lead AVR in acute myocardial infarction

The present study evaluated the prevalence and significance of ST-segment depression (STD) in lead aVR on the admission 12-lead electrocardiogram in 307 consecutive patients with an acute myocardial infarction (AMI) with ST-segment elevation. STD in aVR was present in a significantly higher proportion of patients with inferior/posterior AMIs. Within inferior/posterior AMIs those with STD in aVR had significantly more concomitant STD in V(1), V(2), V(3) and more concomitant STesegment elevation in V(5), V(6) and right precordial leads. These data suggests that STD in aVR may point to a coronary artery with a large area of supply as the culprit vessel responsible for the AMI.     

Differentiation between left circumflex and right coronary artery occlusions: studies on ST-segment deviation during percutaneous transluminal coronary angioplasty

To distinguish between acute occlusion of the right coronary artery (RCA) and the left circumflex artery (LCx) by electrocardiography, we studied ST-segment deviation during balloon inflation in percutaneous transluminal angioplasty. The composite electrocardiographic criteria based on ST-segment deviations increased the diagnostic specificity: that is, the finding of inferior infarction (ST-segment elevation in leads II, III, aVF) without lateral infarction (ST-segment elevation in leads V5,6) was highly suggestive of RCA occlusion (sensitivity and specificity: 35 of 43 cases, 81.4%; and 33 of 36 cases, 91.7%), whereas ST-segment elevation in leads V5,6 (LCx: 23 of 36 cases; 63.9%, RCA: 5 of 43 cases; 11.6%) or isolated ST-segment depression in leads V2-4 (LCx: 9 of 36 cases; 25.0%, RCA: none of 43 cases) was highly suggestive of LCx occlusion. These results indicate that the composite electrocardiographic criteria were useful in predicting the artery involved in acute myocardial infarction, although any single criterion was not sensitive or specific enough to differentiate right from left circumflex coronary artery occlusion.     

Acute myocardial infarction with significant left main coronary artery stenosis, significant 3-vessel coronary artery disease and elevated troponin-I at admission

Exercise-induced ST-segment elevation in lead aVR accompanied by ST-segment elevation in lead V1 might be a specific finding of left main coronary artery (LMCA) stenosis. Lead aVR and lead v1 ST segment elevation has been reported, during an attack of chest pain, in patients with LMCA disease with ST segment depression in leads V3, V4 and V5 (with maximal depression in V4). ST-segment elevation in lead aVR in patients with angina at rest can be related to transmural ischemia of the basal part of the interventricular septum, frequently due to LMCA or multivessel coronary disease too. 3-vessel coronary artery disease (CAD) and LMCA disease show a frequent combination of leads with abnormal ST segments during chest pain with ST-segment depression in leads I II V4-V6, and ST-segment elevation in lead aVR. When ST-segment status in lead aVR combines with troponin T, ST-segment elevation in lead aVR and positive troponin T on admission are useful predictors of LMCA or 3-vessel CAD. We present a case of acute myocardial infarction with significant left main coronary artery stenosis, significant 3-vessel coronary artery disease and elevated troponin I at admission in an 83-year-old Italian woman. Also this case focuses attention on the importance of the recognition of the patterns suspected for LMCA and/or 3-vessel coronary disease.     

93例急性心肌梗死患者的心电图及冠脉造影分析

目的探讨急性心肌梗死患者心电图sT改变的导联与冠状动脉罪犯血管的关系。方法对93例急性心肌梗死患者心电图ST段改变与选择性冠状动脉造影结果进行对比分析。结果心电图V1-V4sT抬高伴Ⅱ、Ⅲ、aVFST段下移的罪犯血管主要为左前降支（LAD）,少数前壁心肌梗死伴下壁sT段抬高;Ⅱ、Ⅲ、aVFST抬高伴V1-V4 ST段下移的主要罪犯血管为右冠状动脉（RCA）,少部分为左回旋支（LCX）,极少部分为LAD;胸前导联T高尖与ST抬高导联不一致可排除LAD;高侧壁Ⅰ、AVLST段抬高多数罪犯血管为LCX。结论心电图ST改变的导联对急性心肌梗死罪犯血管能进行初步预测。     

Electrocardiographic characteristics in angiographically documented occlusion of the dominant left circumflex artery with acute inferior myocardial infarction: limitations of ST elevation III/II ratio and ST deviation in lateral limb leads

Background

The prognosis of dominant left circumflex artery (LCx) occlusion-related inferior acute myocardial infarction (AMI) patients is poor, but the electrocardiographic (ECG) characteristics of this AMI entity have not been described.

Methods

One hundred thirty-five patients with first dominant right coronary artery (RCA) or dominant LCx-related inferior AMI were included. The characteristics of ECG obtained on admission for 55 patients with culprit lesions proximal to the first major right ventricular (RV) branch of dominant RCA (group proximal dominant RCA), 62 patients with culprit lesions distal to the first major RV branch of dominant RCA (group distal dominant RCA), and 18 patients with culprit lesions in dominant LCx (group dominant LCx) were compared.

Results

There were no significant differences among the 3 groups in the prevalence regarding an S/R ratio greater than 1:3 in aVL, ST elevation in aVR (ST↑_aVR), ST depression in aVR (ST↓_aVR) of 1 mm or more, and atrioventricular block. Greater ST elevation in lead III than in II and greater ST depression in aVL than I showed specificity of 17% and 44% to identify dominant RCA as culprit lesion, respectively. All 3 groups could be distinguished on the basis of ST↑_V4R, ST↓_V4R, ST↓_V3/ST↑_III of 1.2 or less, and ST↓_V3/ST↑_III of more than 1.2.

Conclusions

Greater ST elevation in lead III than in II, greater ST depression in aVL than I, and an S/R ratio of greater than 1:3 in aVL were not useful to discriminate between dominant RCA and dominant LCx occlusion-related inferior AMI. ST-segment deviation in lead V₄R and the ratio of ST↓_V3/ST↑_III were useful in predicting the dominant artery occlusion-related inferior AMI.     

Electrocardiographic discrimination of infarct-related artery between left circumflex and right coronary artery: comparison of ST elevation between leads II and III

OBJECTIVES: Admission electrocardiography was evaluated to discriminate left circumflex artery (LCX) versus right coronary artery (RCA) as the cause of acute myocardial infarction. METHODS: Electrocardiographic findings were assessed in patients with RCA (n = 60) and LCX (n = 60) occlusion. RESULTS: ST segment elevation in the inferior leads or right precordial leads was more common in the RCA group. ST segment depression or negative T wave was more common in leads I, aVL in the RCA group. ST segment elevation was more common in leads V5, V6 in the LCX group. ST segment was elevated in inferior leads in 55 patients in the RCA group and 27 patients in the LCX group. Mean ST level was higher in lead III than in lead II in the RCA group, but not in the LCX group. The ST level was higher in lead III than in lead II in 78% of the RCA group, but only 44% of the LCX group (p < 0.01). CONCLUSIONS: Comparison of ST levels between leads II and III, and a three-dimensional analysis in 12-lead electrocardiography is useful for discriminating the left circumflex artery from the right coronary artery as the cause of acute myocardial infarction.     

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 ≥ 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.     

Electrocardiograms during acute occlusion of the left circumflex artery as compared with that of the right coronary artery

To assess the characteristic electrocardiographic (ECG) ST changes during acute occlusion of the left circumflex artery (LCX), we observed ECG changes during percutaneous transluminal coronary angioplasty (PTCA) of the LCX and compared the results with those obtained during right coronary angioplasty. Results were as follows: 1. In the 30 patients who had LCX angioplasty (group LCX), ST-segment elevation occurred most frequently in lead V6 (67.7%) and in lead III (46.7%), but rarely in leads and aVL. ST depression occurred most frequently in lead V3 (80.0%) and in lead V2 (73.3%), but rarely in other leads except for leads I and aVL (23.3%, 33.3%). 2. Four types of ST change in lead combinations were observed. These included: (1) ST elevation in the inferior leads (II, III and aVF), (2) ST elevation in the lateral leads (V5 and V6), (3) ST depression in the anterior leads (V2-V4) and (4) ST depression in the high lateral leads (I and aVL). In group LCX, nine cases (30.0%) manifested all four changes, and six cases (20.0%) revealed only ST depression in the anterior leads without ST changes in other leads. 3. ST depression in the anterior leads and ST elevation in the inferior and lateral leads were observed in nearly equal frequency in patients who received PTCA at the proximal site (Seg. 11) and at the distal site (Seg. 13) in the group LCX. However, ST depression in the high-lateral leads was more frequently observed in the distal than in the proximal cases (66.7% vs 33.3%).(ABSTRACT TRUNCATED AT 400 WORDS)     

The Value of Exercise Electrocardiography and Exercise Thallium-201 Myocardial Perfusion Scanning in Determining the Presence of Single Vessel Coronary Artery Obstruction

Summary: In 39 patients with single vessel coronary artery disease and no previous myocardial infarction, exercise thallium-207 myocardial perfusion scanning and 12 lead exercise electrocardiography (ECG) were compared to see how reliably each method identified the site of coronary artery obstruction. Significant (≥ 70% diameter) stenosis was present in the left anterior descending (LAD) coronary artery in 21 patients, in the right coronary artery (RCA) in 14 patients and in the left circumflex (LCX) in four patients. Thallium defects on the scan in the septa1 (SEPT), anteroseptal (ANT SEPT) and anterior (ANT) segments correlated (P < 0.0005) with LAD disease and defects in the inferior (INF), posteroinferior (POST INF), and posterior (POST) segments correlated (P < 0.0005) with RCA or LCX disease. Exercise induced ST segment elevation in VI and/or AVL correlated with LAD disease. The site of ischaemic ST depression did not correlate with disease in any vessel. ST segment depression in leads L2, 3, AVF (67%) and in leads V4–6 (67%) was most sensitive for detecting patients with LAD disease and ST depression in leads V4–6 was most sensitive (56%) for detecting patients with RCA or LCX disease but neither differentiated LAD from RCAILCX disease.
During exercise induced ischaemia, the site of ST segment depression on the 12 lead exercise ECG will not identify the area of ischaemia in patients with single vessel disease but thallium defects will. In contrast to ST depression, ST elevation in V1 and/or AVL may identify LAD stenosis.     

Value of electrocardiographic algorithm based on "ups and downs" of ST in assessment of a culprit artery in evolving inferior wall acute myocardial infarction

Acute myocardial infarction (AMI) of the inferoposterior wall is due to occlusion of the right coronary artery (RCA) or the left circumflex (LCx) coronary artery. The outcome of patients depends mainly on the culprit artery. Therefore, the presumptive prediction of a culprit artery based on the electrocardiogram recorded at admission is of clinical importance. The aim of this study was to develop a sequential algorithm based on the "ups and downs" of the ST segment in different leads to predict the culprit artery (RCA vs LCx) in cases of inferoposterior AMI. We analyzed electrocardiographic and angiographic findings of 63 consecutive patients with an evolving AMI with ST elevation in the inferior leads (II, III, and aVF) and a single-vessel occlusion. Specificity, sensitivity, and positive and negative predictive values of different electrocardiographic criteria (ups and downs of the ST segment) were studied individually and in combination to find an algorithm that would best predict the culprit artery. The following electrocardiographic criteria were included in the 3-step algorithm: (1) ST changes in lead I, (2) the ratio of ST elevation in lead III to that in lead II, and (3) the ratio of the sum of ST depression in precordial leads to the sum of ST elevation in inferior leads [( summation operator downward arrow ST in leads V(1) to V(3))/( summation operator upward arrow ST in leads II, III, and aVF)]. Application of this sensitive algorithm suggested the location of the culprit coronary artery (RCA vs LCx) in 60 of 63 patients (>95%). The few patients in whom this algorithm did not work were those with a very dominant LCx that presented ST depression of > or =0.5 mm in lead I. In conclusion, careful sequential analysis of an electrocardiogram of an inferoposterior AMI with ST elevation may lead to the identification of a culprit artery.     

Identification of the optimal electrocardiographic leads for detecting acute epicardial injury in acute myocardial infarction

Current coronary care electrocardiographic (ECG) monitoring techniques are aimed at detection of cardiac arrhythmias rather than myocardial ischemia. However, in patients with acute myocardial infarction (AMI) who undergo reperfusion therapy, monitoring ST-segment deviation could provide an early noninvasive indicator of coronary artery reocclusion. In this study, the admission 12-lead ECGs of patients with initial AMI were used to propose optimal lead locations for ST-segment monitoring. The study population was selected from consecutive Duke University Medical Center admissions during 1965 to 1981 who met the following inclusion criteria: chest pain for no more than 8 hours, initial AMI documented by ECG and 3 of 4 enzyme criteria, greater than or equal to 0.1 mV (1 mV = 10 mm) of ST elevation in at least 1 of the standard 12 leads (not aVR) on admission ECG, and no ECG evidence of conduction disturbances, ventricular hypertrophy or tachycardia. ST-segment deviation was quantified; AMI location was assigned based on the lead with maximal deviation. Of the 80 patients who had an inferior AMI, lead III was both the most frequent location for ST elevation (94%) and the most common site with maximal ST deviation. Lead V2 had the highest incidence of ST-segment depression (60%). In the 68 patients who had an anterior AMI, lead V2 had the highest frequency of ST elevation (99%). Leads V2 and V3 were the most common sites of maximal elevation. Thus, for monitoring ST deviation, leads III and V2 may be superior to leads II and V1, which are commonly used in arrhythmia monitoring.(ABSTRACT TRUNCATED AT 250 WORDS)     

常规心电图对前壁下壁心肌梗死罪犯血管的预测价值

目的:分析常规心电图对急性前壁下壁心肌梗死罪犯血管的预测价值。方法:选择41例急性前壁合并下壁ST段抬高的心肌梗死者作为研究对象,按冠脉造影资料将梗死罪犯血管分为右冠病变(RCA)组24例和左前降支病变(LAD)组17例,分别测量常规心电图12导联ST段偏移程度及发生的导联数,以计算比较两组间的差异及对不同冠脉之间的预测价值。结果:(1)两组的基线临床资料无显著差异性;(2)RCA组Ⅱ、Ⅲ、aVF导联ST段抬高幅度总和高于LAD组[(2.46±1.24)vs(1.77±0.61)mm,P0.01],ST段抬高III/II1(66%vs 28%,P0.01)或V1/V31(75%vs 12%,P0.05)在RCA组高于LAD组;LAD组V3导联ST段抬高幅度总和高于RCA组[(1.60±0.36)vs(4.44±2.65)mm,P0.01)。结论:Ⅱ、Ⅲ、aVF、V3导联ST段抬高幅度总和及V1/V3比值在诊断急性下壁前壁心肌梗死中对梗死罪犯血管有重要预测价值。     

The Diagnostic Value of 12‐Lead Electrocardiogram in Predicting Infarct‐Related Artery and Right Ventricular Involvement in Acute Inferior Myocardial Infarction

Background: The aim of the present study was to investigate the predictive value of presentation and 24‐hour electrocardiograms in defining the infarct‐related artery (IRA), its lesion segment, and the right ventricular involvement in acute inferior myocardial infarction (Ml). Methods: One hundred forty‐nine patients with acute inferior MI were included. Infarct‐related artery, its lesion segment, and the validity of new ECG criteria for the diagnosis of right ventricular Ml (RVMI) were investigated by means of criteria obtained from admission and 24‐hour ECGs. Results: The presence of ST‐segment elevation in lead III > lead II criterion (Criterion 1) and ST‐segment depression in lead I > lead aVL criterion (Criterion 2) from admission ECG defined the right coronary artery (RCA) as IRA with a sensitivity of 64% and a specificity of 100%. These two criteria also defined the proximal or mid lesions in RCA as culprit lesions (sensitivity of 99%, specificity of 96%). Absence of these two criteria indicated Cx as IRA with a sensitivity of 50% and a specificity of 97%. The depth of Q wave in lead III > lead II criterion (Criterion 3) had no value for discrimination of IRA, but the width of Q wave in lead III > lead II criterion (Criterion 4) supported the RCA to be IRA with a sensitivity of 60% and a specificity of 61% (Criteria 3 and 4 were obtained from 24‐hour ECGs). The finding of Criterion 1 plus Criterion 5 (ST elevation in V₁ but no ST elevation in V2) on admission ECG had a sensitivity of 63% and a specificity of 99% in the diagnosis of RVMI. Conclusion: We concluded that 12‐lead ECG is a cheap, easy, and readily obtainable diagnostic approach in discrimination of IRA and its culprit lesion segment. However, despite high specificity, due to moderate degree sensitivity, its value for the diagnosis of RVMI is questionable. A.N.E. 2001; 6(3):229–235     

Electrocardiogram patterns in acute left main coronary artery occlusion

Acute coronary syndrome with subtotal occlusion of the left main coronary artery is rather frequently encountered in the catheterization laboratory, whereas survival to hospital admission of sudden total occlusion of the left main coronary artery is rare. The typical electrocardiographic (ECG) finding in cases with preserved flow through the left main is widespread ST-segment depression maximally in leads V4-V6 with inverted T waves and ST-segment elevation in lead aVR. In acute myocardial ischemia without (or with minor) myocardial necrosis, the ECG pattern is transient, whereas persistent ECG changes, usually without development of Q waves, are indicative of myocardial injury. In acute total left main occlusion, severe ischemia may be manifested in the ECG by life-threatening tachyarrhythmias, conduction disturbances, and ST-segment deviation. Because of the potential for life-saving therapeutic options by invasive therapy, the ECG markers of the serious condition should be recognized by the medical profession. Left main occlusion should be suspected in severely ill patients with widespread ST-segment depressions, especially in leads V4-V6 with inverted T waves or ST elevation involving the anterior precordial leads and the lateral extremity leads I and aVL. In addition, lead aVR ST elevation accompanied by either anterior ST elevation or widespread ST-segment depression may indicate left main occlusion.     

Electrocardiographic predictors of culprit artery in acute inferior ST elevation myocardial infarction

Background

In acute inferior ST-segment elevation myocardial infarction (STEMI), multiple electrocardiographic algorithms have been proposed to predict the culprit artery. Our purpose is to review these and compare them to ST depression in lead aVR to predict culprit artery in inferior STEMI.

Methods

In 106 patients with acute inferior STEMI who underwent emergent coronary angiography, we correlated electrocardiographic and angiographic findings pertaining to the culprit artery. We then reviewed the algorithms proposed by Fiol et al and Tierala et al, and applied them and our own from Kanei et al using ST depression in aVR for predicting the left circumflex artery (LCx) as the culprit, to the population. Finally, we compared the sensitivities and specificities of the respective algorithms for predicting the culprit artery.

Results

The sensitivity and specificity of ST depression in lead aVR to predict LCx as the culprit were 53% and 86%, respectively, and 86% and 55%, respectively for predicting the right coronary artery (RCA) as the culprit. When their algorithms were applied to our population, the sensitivities and specificities of Fiol et al and Tierala et al were slightly higher.

Conclusion

Compared to other proposed algorithms, ST depression in aVR is a simple method with satisfactory sensitivity and specificity to predict the culprit artery in inferior STEMI.     

Acute anterior wall myocardial infarction entailing st-segment elevation in lead v1: Electrocardiographic and angiographic correlations

Background: The correlation between ST elevation in lead V₁ during anterior wall acute myocardial infaction (AMI) and the culprit lesion site in the left anterior descending (LAD) coronary artery is poor. Hypothesis: The study was undertaken to assess the electrocardiographic (ECG) characteristics and angiographic significance of ST-segment elevation in lead V¹ during anterior wall acute myocardial infarction (AMI). Methods: Data from 115 patients with anterior wall AMI, who underwent coronary angiography within 14 days of hospitalization, were studied. The admission 12-lead ECG was examined and the coronary angiogram was evaluated for the nature of the conal branch of the right coronary artery (RCA) and for the culprit lesion site in the left anterior descending (LAD) coronary artery. Results: Mean ST-segment deviation and the frequency of patients with ST-segment elevation > 0.1 mV were significantly lower in lead V i than in lead V2 (0.136 $$ 0.111 mV vs. 0.421 $$ 0.260 mV, and 37 vs. 96%, for leads Vi and Vi, respectively). A small conal branch not reaching the interventricular septum (IVS) was more prevalent among patients with ST-segnicni elevation >0.1 mV in lead Vi (67%), whereas a large conal branch was more prevalent in patients with ST-segment deviation (1 mV in that lead (83%, p<0.001). No relation was found between ST-segment deviation in lead V i during anterior wall AMI and the culprit lesion site in the LAD. Conclusion: ST-segment elevation in lead V₁ during first anterior wall AMI was found in one third of the patients, and its magnitude was lower than that in the other precordial leads. ST-segment elevation in lead V₁ favors the presence of a small conal branch of the RCA that does not reach the IVS.