Isolated mid-anterior myocardial infarction: a special electrocardiographic sub-type of acute myocardial infarction consisting of ST-elevation in non-consecutive leads and two different morphologic types of ST-depression

New ECG Algorithm for the Prediction of Culprit Vessel in Acute Myocardial Infarction Involving Lateral Part of the Ventricle: Ilkay Classification

Background

Isolated lateral myocardial infarction sometimes does not meet ST-segment elevation myocardial infarction (STEMI) criteria according to contiguous leads. This condition could cause late diagnosis and the need for revascularization therapy.

Aim

To accurately predict the occlusion of lateral surface of the left ventricle, we defined a new electrocardiogram (ECG) algorithm by using angiographic and electrocardiographic correlations.

Methods

This was a retrospective, multicenter observational study. The study population consisted of 200 patients with STEMI affecting lateral surface of myocardium, between 2021 and 2022. According to the coronary angiography results, we identified 74 eligible patients for study protocol. The study patients were divided into two groups: isolated DB (14 patients) or circumflex obtuse marginal group (60 patients).

Results

ST depression in lead V2 had high positive predictive values for the prediction of obtuse marginal occlusion (positive predictive values (PPV), 100%; negative predictive value (NPV), 90%). ST elevation in V2 in ECG, in conjunction with ST depression in lead III had high positive predictive values for prediction of diagonal branch of LAD. Moreover, the presence of hyperacute T wave (≥10 mm) in lead V2 and ≥2 mm ST depression in lead III had large diagonal branch of LAD (PPV, 98%; NPV, 100%). However, <10 mm T wave in lead V2 and <2 mm ST depression in lead III had small diagonal branch of LAD.

Conclusion

We comprehensively classified the lateral STEMI definition through new electrocardiographic scheme as Ilkay classification, whereby we could accurately predict infarct-related artery and its occlusion level in lateral myocardial infarction.

The South African Flag Sign: An Electrocardiographic Flag for All Coronary Territories?

The South African flag sign (SAFS) is an acute, dynamic electrocardiographic (ECG) finding typically associated with first diagonal (D1) artery occlusion. We report the case of a 47-year-old woman who exhibited this pattern but subsequently revealed the dreaded "widow-maker" lesion (100% occluded proximal left anterior descending [LAD] artery) and severe multivessel disease (90% stenosis of the posterior left ventricular [PLV] artery and 80% stenosis of the left circumflex artery [LCx]).

The Role of ECG in the Diagnosis and Risk Stratification of Acute Coronary Syndromes: an Old but Indispensable Tool

PURPOSE OF REVIEW

Since its inception in 1902 by Willem Einthoven, the electrocardiogram (ECG) has fundamentally undergone minimal technological advances. Nevertheless, its clinical utility is critical, and it remains an essential tool to diagnose, risk stratify, and guide reperfusion and invasive strategies in patients with suspected acute coronary syndromes. ECG reading can be demanding, with many healthcare professionals lacking the necessary expertise to accurately interpret them. This is exacerbated by the need to constantly revisit old dogmas pertinent to the interpretation of ECGs.

RECENT FINDINGS

Notably, ECG leads record the global electrical activity of the heart toward and away from each electrode rather than local events. The long-held central paradigm that the various ECG leads record local events underneath specific electrodes should therefore be reassessed. For example, ST segment elevation in leads V1 and V2 usually denote antero-apical rather than septal infarction, often a misnomer utilized by the majority of clinicians. The ECG diagnosis of ST-elevation myocardial infarction (STEMI) is sometimes challenging and discerning it from non-ST-elevation myocardial infarction (NSTEMI) is of paramount importance to implement timely acute reperfusion therapy. In fact, when qualifications for emergency reperfusion therapy are based on STEMI ECG criteria, nearly one-third of cases with acute coronary occlusion are missed. Diagnostic ST elevation in the absence of left ventricular (LV) hypertrophy or left bundle-branch block (LBBB) is defined by a specific set of sex-specific criteria for new ST elevation at the J point in contiguous precordial or limb leads. However, other ECG criteria need to be kept in mind. These include, but are not limited to, new or presumably new left bundle branch block (LBBB), which is often considered as an STEMI-equivalent; ST depression in two or more precordial leads (V1-V4), denoting a true inferolateral transmural myocardial infarction; and the infrequent presentation with hyperacute T-wave changes. As our understanding of the pathology of ischemic reperfusion injury has evolved and following the introduction of new imaging modalities such as cardiac magnetic resonance imaging, we need to re-assess the old dogmas pertinent to the interpretation of ECGs and update the terms and classifications.

A case of de Winter syndrome presenting with chest tightness

de Winter syndrome, also termed anterior ST-segment elevation myocardial infarction (STEMI) equivalent, is estimated to be present in approximately 2% of patients with acute myocardial infarction, but is often under-recognized by clinicians. Therefore, de Winter syndrome is associated with increased morbidity and mortality. We report a 51-year-old man with typical chest tightness and a characteristic electrocardiographic pattern without classic ST-segment elevation, but with acute nearly total occlusion of the left anterior descending coronary artery. Although the patient presented as a non-STEMI case, the definite diagnosis of de Winter syndrome was made on the basis of clinical and electrocardiographic findings. The patient's symptom of chest tightness was relieved immediately after acute percutaneous coronary intervention and the left ventricular ejection fraction had not deteriorated at 1 month of follow-up.

Isolated ST-Elevation Myocardial Infarction Involving Leads I and aVL: Angiographic and Electrocardiographic Correlations from a Tertiary Care Center

BACKGROUND

Determining the infarct-related artery in STEMI during a coronary angiogram can be challenging due to the affliction of multiple vessels. Isolated STEMI involving only EKG leads I and aVL is infrequent. Localization of infarct-related artery based on EKG findings has not been previously done in this subset.

METHODS

All consecutive de novo acute coronary syndrome (ACS) patients admitted to coronary care unit with ST elevations involving only leads I and aVL were screened for enrollment. Patients with ST elevation in any additional lead and those who refused a coronary angiogram were excluded. Subsequently, a coronary angiogram was done as part of primary PCI or a pharmacoinvasive approach to identify the infract-related artery (IRA). IRA was defined by characteristics of lesion, flow of blood through stenosis, and presence of intracoronary thrombus. Coronary angiogram was interpreted by two independent observers blinded to the EKG findings. ST changes in inferior and precordial leads were analyzed to find ECG predictors of the culprit artery.

RESULTS

A total of 54 eligible patients of ACS were included in the study. The first major diagonal (D1) was the most frequent IRA in 35.2% followed by left circumflex-obtuse marginal (LCX-OM11) in 29.6%, left anterior descending (LAD) in 20.4%, and ramus intermedius (RI) in 14.8%. Out of total patients with ST depression in lead V2, the LCX-OM11 group was IRA in 50% cases while the RI, D1, and LAD groups accounted for 31.8%, 13.6%, and 4.5%, respectively (p < 0.001). Similarly, LCX-OM1 was the most frequent IRA subjects with ST depressions in leads V1 and V3 (44.4%; p = 0.010 and 46.2%; p = 0.003, resp.). On the contrary, in patients with ST depression in lead III, LAD and D1 were the most frequent IRA as compared to LCX-OM1 and RI though statistical significance was not attained (p = 0.857 for lead III). ST-segment depression in lead V2 had a positive predictive value of 60% and a negative predictive value of 100% for LCX-OM1 as IRA. Similarly, ST-segment depression in lead V2 had a positive predictive value of 20% and a negative predictive value of 100% for the RI group.

CONCLUSIONS

In patients presenting with isolated ST elevation in leads I and aVL, the most frequent IRA on angiogram was first diagonal. ST depressions in EKG leads V1-V3 were the most common predictor of LCX-OM1 while those in inferior leads indicated LAD-D1 as the IRA.

A new electrocardiographic pattern indicating inferior myocardial infarction

BACKGROUND

We identified a specific pattern that does not display contiguous ST-segment elevation (STE), indicating acute inferior myocardial infarction (MI) with concomitant critical stenoses on the other coronary arteries. We sought to define the frequency, underlying anatomic substrate, diagnostic power and prognostic implications of this pattern.

METHODS

One thousand patients with a diagnosis of non-STEMI were enrolled as the study group. Within the same date range, all patients with inferior STEMI and 1000 patients, who had been excluded for MI (no-MI), were also enrolled. The coronary angiograms were reviewed by two interventional cardiologists, who were blinded to the ECGs. Echocardiographic wall motion bullseye displays and coronary angiography maps were constructed for each group. The dead or alive status was checked from the electronic national database.

RESULTS

The final study population consisted 2362 patients. The prespecified ECG pattern was observed in 6.3% (61/966) of the non-STEMI cohort and 0.5% (5/1000) of no-MI patients. These patients had a larger infarct size as evidenced by 24-hour troponin levels, higher frequency of angiographic culprit lesion, and higher frequency of composite acute coronary occlusion endpoint compared to their non-STEMI counterparts. On the other hand, they had a similar in-hospital (5% vs. 4%, respectively; P = 0.675) and one-year mortality compared to the patients with inferior STEMI (11% vs. 8%, respectively; P = 0.311).

CONCLUSION

We here define a new ECG pattern indicating inferior MI in patients with concomitant critical lesion(s) in coronary arteries other than the infarct-related artery. Patients with this pattern have multivessel disease and higher mortality.

The diagonal branches and outcomes in patients with anterior ST- elevation myocardial infarction

BACKGROUND

The management of diagonal branch (D) occlusion is still controversary. The association between the flow loss of D and the prognosis remains unclear. We aim to detect the impact of D flow on cardiac function and clinical outcomes in patients with anterior ST-segment elevation myocardial infarction (STEMI).

METHODS

Patients with anterior STEMI undergoing primary percutaneous coronary intervention (PCI) at our clinic between October 2015 and October 2018were reviewed. Anterior STEMI due to left anterior descending artery (LAD) occlusion with or without loss of the main D flow (TIMI grade 0-1 or 2-3) was enrolled in the analysis. The short- and long-term incidence of major adverse cardiac events (MACEs, a composite of all-cause death, target vessel revascularization and reinfarction) and left ventricular ejection fraction (LVEF) were analyzed.

RESULTS

A total of 392 patients (mean age of 63.9 years) with anterior STEMI treated with primary PCI was enrolled in the study. They were divided into two groups, loss (TIMI grade 0-1, n = 69) and no loss (TIMI grade2-3, n = 323) of D flow, before primary PCI. Compared with the group without loss of D flow, the group with loss of D flow showed a lower LVEF post PCI (41.0% vs. 48.8%, p = 0.003). Meanwhile, loss of D flow resulted in the higher in-hospital, one-month, and 18-month incidence of MACEs, especially in all-cause mortality (all p < 0.05). Landmark analysis further indicated that the significant differences in 18-month outcomes between the two groups mainly resulted from the differences during the hospitalization. In addition, multivariate Cox proportional hazards analysis found that D flow loss before primary PCI was independent factor predicting short- and long-term outcomes in patients with anterior STEMI.

CONCLUSION

Loss of the main D flow in anterior STEMI patients was independently associated with the higher in-hospital incidences of MACEs and all-cause death as well as the lower LVEF.

Electrocardiographic findings of acute total occlusion associated with a sub-occlusion involving the left anterior descending and the right coronary artery

BACKGROUND

The ECG characteristics of simultaneous acute occlusion/sub-occlusion of two coronary arteries involving the left anterior descending (LAD) and right (RCA) coronary artery have been rarely described in the literature.

METHODS

We present two patient cases, where one of the arteries was totally occluded and the other one had a sub-occlusion with severely limited flow to demonstrate the ECG characteristics of this severe presentation of acute coronary syndrome.

RESULTS

Two ECG patterns suggested simultaneous occlusions of the RCA and LAD. One pattern was ST-segment elevation (STE) in lead III higher than in lead II with concomitant STE in leads V3-V4. The other pattern was STE in lead III higher than in lead II with the concomitant Dressler - de Winter ECG pattern in leads V2-V4.

CONCLUSIONS

We present two ECG presentations of simultaneous RCA and LAD occlusion/sub-occlusion. We consider these ECG features as high-risk markers in acute ST-elevation myocardial infarction.

Junctional ST-depression and tall symmetrical T-waves with an obtuse marginal artery occlusion: A case report

A 54-year-old man presented to the emergency department with chest pain and electrocardiogram (ECG) changes of acute ST-segment elevation myocardial infarction (STEMI) and junctional ST-depression with tall symmetrical T-waves (de Winter T-wave) in the lateral and inferior leads. Emergent coronary angiography revealed a culprit lesion in the gigantic obtuse marginal artery (OM). This case demonstrates the de Winter T-wave can occur in a patient with an acute occlusion of OM. Emergency physicians, ambulance staff, cardiologists and all involved in STEMI networks should familiarize themselves with this unusual ECG pattern and consider transferring patients for urgent angiography and reperfusion therapy.

Acute diagonal-induced ST-elevation myocardial infarction and electrocardiogram-guidance in the era of primary coronary intervention: New insights into an old tool

BACKGROUND

Previous studies, published before the advent of primary reperfusion, described the electrocardiographic features of ST-segment elevation myocardial infarction (STEMI) caused by total diagonal artery occlusion, as demonstrated at pre-discharge coronary angiography. We aimed to assess the electrocardiographic and echocardiographic features in STEMI unequivocally attributed to a diagonal lesion in the era of primary coronary intervention.

METHODS

The electrocardiograms and echocardiograms of patients sustaining STEMI caused by diagonal artery involvement were compared with those of patients with STEMI attributed to proximal or mid left anterior descending artery (LAD) lesions. ST-segment deviations were measured at four different points in each lead and analyzed against TIMI flow and SNuH score. The electrocardiographic and echocardiographic features of each group were mapped.

RESULTS

In contrast to previous studies claiming an ever-present incidence of at least 1-mm ST-segment elevation in leads I and aVL with diagonal STEMI, we report 86% of any ST-elevation in leads I, aVL and V2 (64-71% for ST-elevation >1 mm). Both higher SNuH score and pre-intervention TIMI flow were associated with larger lateral ST-elevations (85.7% and 86.4-95.5%, respectively). Higher prevalence of ST-depression in the inferior leads reflecting reciprocal changes was observed in patients with diagonal-induced STEMI (57-76% vs. 24-51% in LAD obstructions, p <0.05).

CONCLUSION

The most sensitive and predictive sign for acute ischemia was any degree of ST-deviation measured 1 mm beyond the J point. ST-elevations in I, aVL and V₂, sparing V₃-V₅, strongly favor isolated diagonal lesion. Proximal LAD lesion lacking ST-segment elevations in leads I and aVL is primarily due to wraparound LAD anatomy.

The established electrocardiographic classification of anterior wall myocardial infarction misguides clinicians in terms of infarct location, extent and prognosis

BACKGROUND

The currently used scheme for the classification of infarct location and extent in anterior myocardial infarction (MI) is intuitive rather than being evidence-based, and recent evidence suggests that it may be misleading both in anatomic and prognostic sense.

MATERIAL AND METHODS

Consecutive patients with the diagnosis of anterior MI were enrolled. All electrocardiograms (ECG) were first classified according to established scheme and then reassessed using newer criteria for angiographic site of occlusion. The site of left anterior descending (LAD) occlusion was determined using multiple angiographic views. Clinic, echocardiographic and angiographic outcomes were compared.

RESULTS

A total of 379 anterior MI cases were enrolled, final study population consisted of 267 patients. The established scheme did not predict infarct size or adverse outcomes. Location of the myocardium subtended by the occluded coronary network did not match with the anatomic location as ECG classification implies. Many high-risk patients with proximal LAD were classified as "anteroseptal", whereas the majority of the patients labeled as "extensive anterior MI" had in fact distal occlusions. On the other hand, expert interpretation was fairly accurate in predicting adverse outcomes and the site of angiographic involvement.

CONCLUSION

Classifying patients according to the established scheme neither gives prognostic information nor accurately localizes infarction. It should be regarded as obsolete and its use should be abandoned. Instead, the extent of infarction can be inferred from newer criteria provided by the angiographic correlation studies.

Correlation of electrocardiogram and regional cardiac magnetic resonance imaging findings in ST-elevation myocardial infarction: a literature review

BACKGROUND

Patients with acute ST-elevation myocardial infarction (STEMI) benefit substantially from emergent coronary reperfusion. The principal mechanism is to open the occluded coronary artery to minimize myocardial injury. Thus the size of the area at risk is a critical determinant of the patient outcome, although other factors, such as reperfusion injury, have major impact on the final infarct size. Acute coronary occlusion almost immediately induces metabolic changes within the myocardium, which can be assessed with both the electrocardiogram (ECG) and cardiac magnetic resonance (CMR) imaging.

METHODS

The 12-lead ECG is the principal diagnostic method to detect and risk-stratify acute STEMI. However, to achieve a correct diagnosis, it is paramount to compare different ECG parameters with golden standards in imaging, such as CMR. In this review, we discuss aspects of ECG and CMR in the assessment of acute regional ischemic changes in the myocardium using the 17 segment model of the left ventricle presented by American Heart Association (AHA), and their relation to coronary artery anatomy.

RESULTS

Using the 17 segment model of AHA, the segments 12 and 16 remain controversial. There is an important overlap in myocardial blood supply at the antero-lateral region between LAD and LCx territories concerning these two segments.

CONCLUSION

No all-encompassing correlation can be found between ECG and CMR findings in acute ischemia with respect to coronary anatomy.

The absence of the ST-segment elevation in acute coronary artery thrombosis: what does not fit, the patient or the explanation?

In a few patients with acute proximal thrombotic occlusion of the left anterior descending coronary artery (LAD), tall ischemic T waves never evolve into ST-segment elevation. This was recently inaccurately reported as a "novel sign" of proximal LAD occlusion. It has been speculated that the absence of ST-segment elevation could be attributed to the large area of transmural ischemia, the anatomic variant of Purkinje fibers, or to lack of activation of sarcolemal adenosine triphosphate-potassium channels. This electrocardiographic picture was recently explained by changes in the subendocardial but not in the epicardial action potential, suggesting subendocardial ischemia as the underlying mechanism. We present a patient with thrombotic lesion of proximal LAD, static precordial ST-segment depression, and tall T waves who underwent primary percutaneous intervention and stent placement. Surprisingly, total thrombotic stent occlusion on the following day was associated with ST-segment elevation in precordial leads, indeed supporting the concept of the regional subendocardial ischemia that was first described more than a decade ago.

Electrocardiographic differentiation between occlusion of the first diagonal branch and occlusion of the left anterior descending coronary artery

PURPOSE

We sought to electrocardiographically distinguish ST-segment elevation (STE)-acute myocardial infarction (AMI) caused by occlusion of the first diagonal branch (D1) from STE-AMI caused by occlusion of the left anterior descending coronary artery (LAD).

METHODS

We examined 28 patients with STE-AMI caused by D1 occlusion (G-D) and 342 with STE-AMI caused by LAD occlusion (G-L).

RESULTS

G-D had a higher prevalence of STE > or = 0.5 mm in each of leads I and aVL and a lower prevalence of STE > or = 1 mm in each of leads V(1) through V(6) than G-L. The prevalence of STE > or = 0.5 mm in lead aVL without STE > or = 1 mm in lead V(1) was higher in G-D (82.1%) than in G-L (9.4%, P < .01).

CONCLUSION

ST-segment elevation > or = 0.5 mm in lead aVL without STE > or = 1 mm in lead V(1) may be useful to distinguish STE-AMI caused by occlusion of the D1 from STE-AMI caused by occlusion of the LAD.

An electrocardiographic algorithm for the prediction of the culprit lesion site in acute anterior myocardial infarction

BACKGROUND

Although the 12-lead electrocardiogram (ECG) has been found useful in identifying the left anterior descending (LAD) coronary artery as the infarct-related artery in acute myocardial infarction (MI), it has traditionally been felt to be incapable of localizing the culprit lesion within the LAD itself. Such a capability would be important, because anterior MI due to proximal LAD lesions carry a much worse prognosis than those due to more distal or branch vessel lesions.

HYPOTHESIS

This study investigated whether certain ECG variables--especially an ST-segment injury pattern in leads aVL and/or V1--would correlate with culprit lesion site, and an ECG algorithm was developed to predict culprit lesion site.

METHODS

The initial ECGs of 55 patients who had undergone cardiac catheterization after an anterior or lateral MI were reviewed to identify the leads with an ST-segment injury pattern; the corresponding catheterization films were then reviewed to identify the location of the culprit lesion; and these separate findings were then compared.

RESULTS

The sensitivity and specificity of an ST-injury pattern in aVL in predicting a culprit lesion before the first diagonal branch were 91 and 90%, respectively; the same values in predicting a lesion prior to the first septal branch were 85 and 78%. ST-segment elevation in V1, on the other hand, was a much less sensitive and specific predictor of a preseptal lesion. Overall, our algorithm correctly identified the culprit lesion location in 82% of our patients.

CONCLUSION

Based on our findings, we conclude that a ST-segment injury pattern in aVL during an anterior myocardial infarction predominantly reflects a proximal LAD lesion and therefore constitutes a high-risk finding.

Value of T-wave direction with lead III ST-segment depression in acute anterior wall myocardial infarction: electrocardiographic prediction of a "wrapped" left anterior descending artery

BACKGROUND

Lead III ST-segment depression during acute anterior wall myocardial infarction (AMI) has been attributed to reciprocal changes. However, the value of the T-wave direction (positive or negative) in predicting the site of obstruction and type of the left anterior descending (LAD) artery is not clear and has not been studied before.

HYPOTHESIS

The aim of the study was to assess retrospectively the correlation between two patterns of lead III ST-segment depression, and type of LAD artery and its level of obstruction during first AMI.

METHODS

The study group consisted of 48 consecutive patients, admitted to the coronary care unit for first AMI, who showed ST-segment elevation in lead a VL and ST-segment depression in lead III on admission 12-lead electrocardiogram. The patients were divided by T-wave direction into Group 1 (n = 31), negative T wave, and Group 2 (n = 17), positive T wave. The coronary angiogram was evaluated for type of LAD ("wrapped", i.e., surrounding the apex or not), site of obstruction (pre- or postdiagonal branch), and other significant coronary artery obstructions.

RESULTS

Mean lead III ST-segment depression was 1.99 +/- 1.32 mm in Group 1 and 1.13 +/- 0.74 mm in Group 2 (p = 0.004); mean ST-segment elevation in a VL was 1.35 +/- 0.84 mm and 1.23 +/- 0.5 mm, respectively (p = 0.5). A wrapped LAD was found in 12 patients (38.7%) in Group 1 and in 13 in Group 2 (76.4%) (p = 0.02). The sensitivity of lead III ST-segment depression with positive T wave to predict a wrapped LAD was 52%, and the specificity was 82% with a positive predictive value of 76%. On angiography, 25 patients (80%) in Group 1 and 13 (76%) in Group 2 had prediagonal occlusion of the LAD (p = 0.77). No significant difference between groups was found for right and circumflex coronary artery involvement or incidence of multivessel disease.

CONCLUSIONS

The presence of lead III ST-segment depression with positive T wave associated with ST-segment elevation in a VL in the early course of AMI can serve as an early electrocardiographic marker of prediagonal occlusion of a "wrapped" LAD.

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.

Predictive value of admission electrocardiogram for multivessel disease in acute anterior and anterior-inferior myocardial infarction

BACKGROUND

Our aim was to investigate the correlation between admission ECG and coronary angiography findings in terms of predicting the culprit vessel responsible for the infarct or multivessel disease in acute anterior or anterior-inferior myocardial infarction (AMI).

METHODS

We investigated 101 patients with a diagnosis of anterior AMI with or without ST-segment elevation or ST-segment depression in at least two leads in DII, III, aVF. The patients were classified as those with vessel involvement in the left anterior descending (LAD) coronary artery and patients with multivessel disease. Vessel involvement in LAD + circumflex artery (Cx) or LAD + right coronary artery (RCA) or LAD + Cx + RCA were considered as multivessel disease. Thus, (a) anterior AMI patients with reciprocal changes in inferior leads, (b) anterior AMI patients with inferior elevations, (c) all anterior AMI patients according to the ST-segment changes in the inferior region were analyzed according to the presence of LAD or multivessel involvement.

RESULTS

Presence of ST-segment depression in aVL and V6 was significantly correlated with the presence of multivessel disease in anterior AMI patients with reciprocal changes in the inferior leads (P = 0.005 and P = 0.003, respectively). No statistically significant difference between the leads were detected in terms of ST-segment elevation in predicting vessel involvement in the two groups of anterior AMI patients with inferior elevations. When all the patients with anterior AMI were analyzed, the presence of ST-segment depression in leads aVL, V4, V5 and V6 were significantly associated with the presence of multivessel disease (P = 0.035, P = 0.010, P = 0.011, P = 0.001, respectively).

CONCLUSIONS

The presence of ST-segment depression in anterolateral leads in the admission ECG of anterior AMI patients with reciprocal changes in inferior leads was associated with multivessel disease.

Electrocardiographic Diagnosis of ST-elevation Myocardial Infarction

The ECG is an essential part of the initial evaluation of patients who have chest pain, especially in the immediate decision-making process in patients who have ST-elevation myocardial infarction. This article reviews and summarizes the current information that can be obtained from the admission ECG in patients who have ST-elevation acute myocardial infarction, with an emphasis on: (1) prediction of final infarct size, (2) estimation of prognosis, and (3) the correlations between various ECG patterns and the localization of the infarct and the underlying coronary anatomy.

Non-invasive estimation of myocardial infarction by means of a heart-model-based imaging approach: A simulation study

In the study, a new myocardial infarction (MI) estimation method was developed for estimating MI in the three-dimensional myocardium by means of a heart-model-based inverse approach. The site and size of MI are estimated from body surface electrocardiograms by minimising multiple objective functions of the measured body surface potential maps (BSPMs) and the heart-model-generated BSPMs. Computer simulations were conducted to evaluate the performance of the developed method, using a single-site MI and dual-site MI protocols. The simulation results show that, for the single-site MI, the averaged spatial distance (SD) between the weighting centres of the 'true' and estimated MIs, and the averaged relative error (RE) between the numbers of the 'true' and estimated infarcted units are 3.0 +/- 0.6/3.6 +/- 0.6 mm and 0.11 +/- 0.02/0.14 +/- 0.02, respectively, when 5 microV/10 microV Gaussian white noise was added to the body surface potentials. For the dual-site MI, the averaged SD between the weighting centres of the 'true' and estimated MIs, and the averaged RE between the numbers of the 'true' and estimated infarcted units are 3.8 +/- 0.7/3.9 +/- 0.7mm and 0.12 +/- 0.02/0.14 +/- 0.03, respectively, when 5 microV/10 microV Gaussian white noise was added to the body surface potentials. The simulation results suggest the feasibility of applying the heart-model-based imaging approach to the estimation of myocardial infarction from body surface potentials.

The electrocardiogram in ST elevation acute myocardial infarction: correlation with coronary anatomy and prognosis

The electrocardiogram is considered an essential part of the diagnosis and initial evaluation of patients with chest pain. This review summarises the information that can be obtained from the admission electrocardiogram in patients with ST elevation acute myocardial infarction, with emphasis on: (1) prediction of infarct size, (2) estimation of prognosis, and (3) the correlations between various electrocardiographic patterns and the localisation of the infarct and the underlying coronary anatomy.

Electrocardiographic diagnosis of acute myocardial infarction: Current concepts for the clinician

BACKGROUND

Over the past 2 decades, the 12-lead electrocardiogram has attained special significance for the diagnosis and triage of patients with chest pain because timely detection of myocardial injury and a rapid assessment of myocardium at risk proved pivotal to implementing effective reperfusion therapies during acute myocardial infarction. However, this wealth of information could still be underutilized by clinicians who may restrict their diagnostic quest in patients with chest pain to the more classic electrocardiographic signs.

METHODS

The medical literature on electrocardiographic manifestations of acute myocardial infarction was extensively reviewed.

RESULTS

The widespread utilization of both coronary angiography and methods to determine myocardial function and metabolism in patients with acute myocardial infarction over the last 10 years has provided the means for rigorous comparisons with electrocardiographic information. We summarize these electrocardiographic signs and patterns in terms of their relevance to the clinician to help reduce the incidence of "nondiagnostic electrocardiograms" and improve timely decision-making.

CONCLUSIONS

The electrocardiogram continues to be an invaluable tool in the initial evaluation of patients with chest pain. The plethora of data currently available on electrocardiographic changes correlating with myocardial injury allows clinicians to make faster and better decisions than ever before.

Prediction of the site of total occlusion in the left anterior descending coronary artery using admission electrocardiogram in anterior wall acute myocardial infarction

In anterior acute myocardial infarction, ST elevation in aVL and ST depression in II, III, and aVF predict a culprit lesion in the left anterior descending artery proximal to the origin of the first diagonal branch, with good specificity and positive predictive value. Inferior ST depression is not related to remote ischemia but represents an electrocardiographic phenomenon reciprocal to ST elevation in aVL.

Importance of the conal branch of the right coronary artery in patients with acute anterior wall myocardial infarction: electrocardiographic and angiographic correlation

OBJECTIVES

This study assessed prospectively the correlation between the conal branch of the right coronary artery and the pattern of ST segment elevation in leads V1 and V3R during anterior wall acute myocardial infarction (AMI).

BACKGROUND

The traditional electrocardiographic (ECG) definition of anteroseptal AMI-ST segment elevation in leads V1 to V3-has recently been challenged. The significance of ST segment elevation in lead V1 during anterior wall AMI is unclear.

METHODS

The admission 12-lead ECG with additional lead V3R and the coronary angiograms performed within 10 days of hospital admission were evaluated in 28 consecutive patients (mean age +/- SD 62 +/- 9 years) admitted to the coronary care unit with anterior wall AMI. Patients were classified into two groups according to the magnitude of ST segment elevation in lead V1: group A (elevation > or = 1.5 mm, n = 12) and group B (elevation < 1.5 mm, n = 16). Two types of conal branch were identified: small (not reaching the interventricular septum [IVS]) and large (reaching the IVS).

RESULTS

ST segment elevation in lead V3R was found in 11 (92%) and 6 (37%) patients from group A and group B, respectively (p < 0.001); a small conal branch was seen in 10 (83%) and 3 (19%) patients, respectively (p < 0.001). Ten patients (all from group B) had a large conal branch.

CONCLUSIONS

ST segment elevation in lead V1 in the admission ECG of patients with anterior wall AMI is strongly related to ST segment elevation in lead V3R and is associated with a small conal branch. Our findings suggest that lead V1 reflects the right paraseptal area supplied by the septal branches of the left anterior descending coronary artery (LAD), alone or together with the conal branch. The absence of ST segment elevation in lead V1 during anterior AMI suggests that the IVS is protected by a large conal branch in addition to the septal branches of the LAD (double circulation).

Acute myocardial infarction entailing ST-segment elevation in lead aVL: electrocardiographic differentiation among occlusion of the left anterior descending, first diagonal, and first obtuse marginal coronary arteries

Acute myocardial infarction with ST elevation in lead aVL may represent involvement of the first diagonal or the first obtuse marginal branch. This study assesses the correlation among different electrocardiographic patterns of acute myocardial infarction with ST elevation in aVL and the site of the infarct-related artery occlusion. Patients who underwent coronary angiography within 14 days of infarction with an unequivocal culprit lesion were included. Fifty-seven patients were evaluated. The culprit lesion was in the left anterior descending coronary artery proximal to the first diagonal, first diagonal, and first obtuse marginal branches, in 38, 8, and 11 patients, respectively. ST elevation in aVL and V2 through V5 signifies left anterior descending artery occlusion proximal to the first diagonal branch (positive predictive value [PPV] and negative predictive value [NPV] of 95% and 94%, respectively). ST elevation in aVL and V2, not accompanied by ST elevation in V3 through V5, favors occlusion of the first diagonal branch (PPV, 89%; NPV, 100%). ST elevation in aVL accompanied by ST depression in V2 predicts obstruction of the first obtuse marginal branch (PPV, 100%; NPV, 98%).