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The Fourth Universal Definition of Myocardial Infarction (FUDMI) focuses on the distinction between nonischemic myocardial injury and myocardial infarction (MI), along with the role of cardiovascular magnetic resonance, in order to define the etiology of myocardial injury. As a consequence, there is less emphasis on updating the parts of the definition concerning the electrocardiographic (ECG) changes related to MI. Evidence of myocardial ischemia is a prerequisite for the diagnosis of MI, and the ECG is the main available tool for (a) detecting acute ischemia, (b) triage, and (c) risk stratification upon presentation. This review focuses on multiple aspects of ECG interpretation that we firmly believe should be considered for incorporation in any future update to the Universal Definition of MI., (© 2020 The Authors. Annals of Noninvasive Electrocardiology published by Wiley Periodicals LLC.)

We describe a patient with acute coronary syndrome, presenting with upsloping ST depression in leads I, II, V3-V6 and ST elevation in lead aVR. Coronary angiography revealed spontaneous dissection in a big, dominant left circumflex artery. No other lesions identified. During stenting of the dissection site, the distal left circumflex, supplying a large posterior descending artery was occluded, resulting in ST elevation myocardial infarction with ST elevation in lead III and aVF, but not II. This pattern is considered to represent right coronary artery infarction, rather than left circumflex infarction., (© 2018 Wiley Periodicals, Inc.)

The electrocardiogram (ECG) is the most widely used imaging tool helping in diagnosis and initial management of patients presenting with symptoms compatible with acute coronary syndrome. Acute ischemia affects the configuration of the QRS complexes, the ST segments and the T waves. The ECG should be read along with the clinical assessment of the patient. ST segment elevation (and ST depression in leads V1 -V3 ) in patients with active symptoms usually indicates acute occlusion of an epicardial artery with ongoing transmural ischemia. These patients should be triaged for emergent reperfusion therapy per current guidelines. However, many patients have ST segment elevation secondary to nonischemic causes. ST depression in leads other than V1 -V3 usually are indicative of subendocardial ischemia secondary to subocclusion of the epicardial artery, distal embolization to small arteries or spasm supply/demand mismatch. ST depression may also be secondary to nonischemic etiologies, such as left ventricular hypertrophy, cardiomyopathies, etc. Knowing the clinical scenario, comparison to previous ECG and subsequent ECGs (in cases that there are changes in the quality or severity of symptoms) may add in the diagnosis and interpretation in difficult cases. This review addresses the different ECG patterns, typically seen in patients with active symptoms, after resolution of symptoms and the significance of such changes when seen in asymptomatic patients., (© 2014 Wiley Periodicals, Inc.)

Background: We will focus our attention in this article in the ECG changes of classical Prinzmetal angina that occur during occlusive proximal coronary spasm usually in patients with normal or noncritical coronary stenosis., Results: The most important ECG change during a focal proximal coronary spasm is in around 50% of cases the appearance of peaked and symmetrical T wave that is followed, if the spasm persist, by progressive ST-segment elevation that last for a few minutes, and later progressively resolve. The most frequent ECG changes associated with ST-segment elevation are: (a) increased height of the R wave, (b) coincident S-wave diminution, (c) upsloping TQ in many cases, and (d) alternans of the elevated ST-segment and negative T wave deepness in 20% of cases. The presence of arrhythmias is very frequent during Prinzmetal angina crises, especially ventricular arrhythmias. The prevalence and importance of ventricular arrhythmias were related to: (a) duration of episodes, (b) degree of ST-segment elevation, (c) presence of ST-T wave alternans, and (d) the presence of >25% increase of the R wave., Conclusions: The incidence of Prinzmetal angina is much lower then 50 years ago for many reasons including treatment with calcium channel blocks to treat hypertension and ischemia heart disease and the decrease of smoking habits., (© 2014 Wiley Periodicals, Inc.)

Background: For many years was considered that negative T wave in ischemic heart disease represents ischemia and for many authors located in subepicardial area., Methods: We performed a review based in the literature and in the experience of the authors commenting the real significance of the presence of negative T wave in patients with ischemic heart disease., Results: The negative T wave may be of primary or secondary type. Negative T wave observed in ischemic heart disease are of primary origin, therefore not a consequence of abnormal repolarization pattern. The negative T wave of ischemic origin presents the following characteristics: (1) are symmetrical and of variable deepness; (2) present mirror patterns; (3) starts in the second part of repolarization; and (4) may be accompanied by positive or negative U wave. The negative T wave of ischemic origin may be seen in the following clinical settings: (1) postmyocardial infarction due to a window effect of necrotic zone and (2) as a consequence of reperfusion in case of aborted MI when the artery has opened spontaneously, or after fibrinolysis, PCI, or coronary spasm., Conclusion: Acute ongoing ischemia do not cause negative T wave. This pattern appears when the ongoing ischemia is vanishing or in the chronic phase. In all these cases the cause of negative T wave is not located in the subepicardial area. Furthermore, positive exercise testing is expressed by ST depression never by isolated negative T wave. There are many circumstances that may present negative T wave outside ischemic heart disease and that have been discussed in this paper., (© 2014 Wiley Periodicals, Inc.)

In many cases, failure to perform an electrocardiogram according to established standards can lead to incorrect diagnosis. When this error involves a disease that can result in sudden death such as Brugada syndrome, diagnostic procedures are not without risk for the patient. A 20 year-old man visited his family doctor for atypical chest pain some time before. Electrocardiography (ECG) showed sinus rhythm of 47 bpm with striking ST-elevation in V1-V3 suggestive of the Brugada pattern. Sometimes, the different low-frequency components of the ECG, such as the ST segment, may be distorted by high cutoff filters resulting in diagnostic errors [Am J Cardiol 2012;110:318-320]. Faced with an apparent Brugada syndrome pattern on ECG, clinicians should ensure the recording was correctly made., (Copyright © 2014 Elsevier Inc. All rights reserved.)

In acute coronary syndromes, the electrocardiogram (ECG) provides important information about the presence, extent, and severity of myocardial ischemia. At times, the changes are typical and clear. In other instances, changes are subtle and might be recognized only when ECG recording is repeated after changes in the severity of symptoms. ECG interpretation is an essential part of the initial evaluation of patients with symptoms suspected to be related to myocardial ischemia, along with focused history and physical examination. Patients with ST-segment elevation on their electrocardiogram and symptoms compatible with acute myocardial ischemia/infarction should be referred for emergent reperfusion therapy. However, it should be emphasized that a large number of patients may have ST-elevation without having acute ST-elevation acute coronary syndrome, while acute ongoing transmural ischemia due to an abrupt occlusion of an epicardial coronary artery may occur in patients with ST-elevation less than the thresholds defined by the guidelines. Up-sloping ST-segment depression with positive T waves is increasingly recognized as a sign of regional subendocardial ischemia associated with severe obstruction of the left anterior descending coronary artery. Widespread ST-segment depression, often associated with inverted T waves and ST-segment elevation in lead aVR during episodes of chest pain, may represent diffuse subendocardial ischemia caused by severe coronary artery disease. In case of hemodynamic compromise, urgent coronary angiography has been increasingly recommended for these patients., (©2013 Wiley Periodicals, Inc.)

Acute coronary syndromes due to involvement of the left main trunk usually present with subtotal occlusion and electrocardiographic pattern with predominant ST depression (non-ST-elevation myocardial infarction). The cases with complete occlusion frequently present an ST-elevation myocardial infarction pattern, but these patients usually die before reaching the hospital. We present a series of 7 patients with total left main trunk occlusion without collateral circulation showing ST-elevation myocardial infarction pattern. The electrocardiographic pattern is similar to left anterior descending coronary artery proximal occlusion to first septal and first diagonal but without ST elevation in V(1) and aVR because of left circumflex coronary artery compromise. In 4 (60%) of 7 of cases, there is also advanced right bundle-branch block plus superoanterior hemiblock. Despite severe clinical state at entrance (5/7 presented cardiac arrest/cardiogenic shock), 3 patients (43%) survived after percutaneous coronary intervention., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Acute coronary syndromes (ACS) with narrow QRS are divided into 2 groups: ST-elevation ACS that requires emergency percutaneous coronary intervention, and non-ST elevation ACS. The classification of ACS into these 2 groups is not always straightforward. In this document, we discuss several electrocardiogram patterns of acute ischemia that are often misinterpreted. We suggest that any new recommendations or guidelines from the Scientific Societies should acknowledge these aspects of electrocardiogram interpretation by including appropriate diagnostic criteria that should prove helpful for the optimal management of patients with ACS., (Copyright © 2012 Elsevier Inc. All rights reserved.)

The aim of this study was to describe differences in the characteristics and short- and long-term prognoses of patients with first acute myocardial infarction (MI) according to the presence of ST-segment elevation or non-ST-segment elevation. From 2001 and 2003, 2,048 patients with first MI were consecutively admitted to 6 participating Spanish hospitals and categorized as having ST-segment elevation MI (STEMI), non-ST-segment elevation MI (NSTEMI), or unclassified MI (pacemaker or left bundle branch block) according to electrocardiographic results at admission. The proportions of female gender, hypercholesterolemia, hypertension, and diabetes were higher among NSTEMI patients than in the STEMI group. NSTEMI 28-day case fatality was lower (2.99% vs 5.26%, p = 0.02). On multivariate analysis, the odds ratio of 28-day case fatality was 2.23 for STEMI patients compared to NSTEMI patients (95% confidence interval 1.29 to 3.83, p = 0.004). The multivariate adjusted 7-year mortality for 28-day survivors was higher in NSTEMI than in STEMI patients (hazard ratio 1.31, 95% confidence interval 1.02 to 1.68, p = 0.035). However, patients with unclassified MI presented the highest short- and long-term mortality (11.8% and 35.4%, respectively). The excess of short-term mortality in unclassified and STEMI patients was mainly observed in those patients not treated with revascularization procedures. In conclusion, patients with first NSTEMI were older and showed a higher proportion of previous coronary risk factors than STEMI patients. NSTEMI patients had lower 28-day case fatality but a worse 7-year mortality rate than STEMI patients. Unclassified MI presented the worst short- and long-term prognosis. These results support the invasive management of patients with acute coronary syndromes to reduce short-term case fatality., (Copyright © 2011 Elsevier Inc. All rights reserved.)

The electrocardiogram (ECG) remains the most immediately accessible and widely used diagnostic tool for guiding emergency treatment strategies. The ECG recorded during acute myocardial ischemia is of diagnostic, therapeutic, and prognostic significance. In patients with myocardial ischemia as a result of decreased blood supply, the initial 12-lead ECG typically shows (1) predominant ST-segment elevation (STE) as part of STE acute coronary syndrome (STE-ACS), or (2) no predominant STE, that is, non-STE ACS (NSTE-ACS). Patients with predominant STE are classified as having either aborted myocardial infarction (MI) or ST-elevation MI (STEMI) based on the absence or presence of biomarkers of myocardial necrosis. The MI may be aborted either by spontaneous or therapeutic reperfusion of the ischemic myocardium before development of myocardial cell necrosis. NSTE-ACS patients are classified as having either unstable angina or NSTE-MI, based also on the absence or presence of biomarkers of mycardial necrosis. The information obtained from the 12-lead ECG at presentation should be complemented by repeated ECGs especially during symptoms indicative of ischemia and, if applicable, by comparing the findings with reference ECGs. Also, continuous ECG recording in a coronary care setting, including the comparison of ECGs with and without pain, adds to the information gained at patient presentation. In this article, mechanisms of ischemic ECG changes and the ECG patterns recorded in both STE-ACS and NSTE-ACS are described. ECG patterns of NSTE-ACS, which include ST depression, negative T wave, and even normal ECG, need to be better defined in future studies to correlate them with the severity and extent of ischemia and to explore to what extent they are explained by acute active ischemia or represent consequences of ischemia. One of the aims of this article is to propose a classification of the ECG patterns encountered in different clinical scenarios of ACS. How these patterns will aid in guiding the diagnostic and therapeutic process is discussed., (2010 Elsevier Inc. All rights reserved.)

This review from the Clinical Cardiology and Outpatient Section of the Spanish Society of Cardiology details recent progress in the field of clinical cardiology. On this occasion, the emphasis is on advances in surface electrocardiography and cardiovascular disease in women. In addition, the review contains a brief overview of those major new developments in therapy that have had the greatest impact on daily clinical practice and summarizes the activities of the Clinical Cardiology and Outpatient Section.

Background: Early prediction of proximal left anterior descending coronary artery (LAD) occlusion is essential from a clinical point of view, Hypothesis: To develop an electrocardiogram (ECG) algorithm based on ST-segment deviations to predict the location of occlusion of LAD as a culprit artery., Methods: ECG and angiographic findings were correlated in 100 patients with an ST-segment elevation myocardial infarction (MI) in precordial leads V(1), V(2), and V(4) through V(6)., Results: ST-depression > or = 2.5 mm in leads III + ventricular fibrillation (VF) presents sensitivity (SE) of 77% and specificity (SP) of 84% for LAD occlusion proximal to the first diagonal artery (D1). ST-segment in III + VF isoelectric or elevated, presents SE of 44% and SP of 100% for LAD occlusion distal to D1. Subsequent analysis of the equation summation operator of ST-deviation in VR + V(1) - V(6) < 0, allows us to predict occlusion distal to first septal artery (S1) with 100% SP. On the other hand, any ST-depression in III + VF > 0.5 mm + summation operator of ST-deviation in VR + V(1) - V(6) > or = 0 identifies a high-risk group (lower ejection fraction, worse Killip findings, higher peak of CPK and CK-MB, and major adverse cardiac events [MACE]: death, reinfarction, recurrent angina, persistent left ventricular failure, or sustained ventricular arrhythmia during hospitalization)., Conclusions: This sequential ECG algorithm based on ST-segment deviations in different leads allowed us to predict the location of occlusion in LAD with good accuracy. Cases with proximal LAD occlusion present the most markers of poor prognosis. We recommend the use of the algorithm in everyday clinical practice.

Guidelines recommend that patients with suggestive symptoms of myocardial ischemia and ST-segment elevation (STE) in > or =2 adjacent electrocardiographic leads should receive immediate reperfusion therapy. Novel strategies aimed to reduce door-to-balloon time, such as prehospital wireless electrocardiographic transmission, may be dependent on the interpretation accuracy of the electrocardiogram (ECG) readers. We assessed the ability of experienced electrocardiographers to differentiate among STE, acute STE myocardial infarction (STEMI), and nonischemic STE (NISTE). A total of 116 consecutive ECGs showing STE were studied. Fifteen experienced cardiologists were asked to decide, based on the ECG and assuming that the patient had compatible symptoms, whether they would send each patient for primary percutaneous coronary intervention (PPCI). If NISTE was chosen, the reader selected 1 or more 12 possible options to explain the choice. Of 116 patients, only 8 had STEMI. The percentage of ECGs for which PPCI was recommended for the patient by the individual readers varied widely (7.8% to 33%). There was no significant difference between the North American and Other Countries readers (p = 0.13). The sensitivity and specificity of the individual readers ranged from 50% to 100% (average 75%) and 73% to 97% (average 85%), respectively. There were broad inconsistencies among the readers in the chosen reasons used to classify NISTE. In conclusion, we found wide variations among experienced electrocardiographers in reading ECGs with STE and differentiating STEMI with need for PPCI from NISTE. There is a need to revise our current electrocardiographic criteria for differentiating STEMI from NISTE.

Aims: To study the different QRS patterns in leads V1 and V2 in first inferior, lateral, and combined inferolateral myocardial infarction (MI) to recognize which are the ECG criteria that best define the presence of lesions isolated to the anatomically lateral wall of the left ventricle., Methods and Results: We studied consecutive patients with first inferior (15), lateral (9), or inferolateral (21) MI with reference to contrast enhanced cardiac magnetic resonance (CE-CRM). We measured the R-wave amplitude and duration, the R/S ratio, and the T-wave amplitude and polarity in leads V1 and V2. The specificity of the V1 criteria for lateral MI, that is, R/S amplitude ratio 1 or greater and R duration 40 milliseconds or longer, is very high but its sensitivity is low. We defined 2 new criteria, R/S of 0.5 or greater and R amplitude in V1 greater than 3 mm, with each achieving a sensitivity of 73.3% and specificity of 93.3% for lateral/inferolateral MI location., Conclusions: (1) New ECG criteria for lateral MI (R/S ratio in V1 > or =0.5 and R amplitude in V1 >3 mm) present very high specificity and lower but very acceptable sensitivity for lateral MI. (2) New criteria based on R waves in V2 or T waves in V1 to V2 do not discriminate between inferior and lateral MI. (3) The classical criteria (R/S amplitude ratio > or =1 and R duration > or =40 ms in V1) attain very high specificity but much lower sensitivity than the new criteria.

Q-wave myocardial infarction (MI) location is generally based on a pathologic correlation first proposed >50 years ago. Despite the proved reliability of contrast-enhanced cardiovascular magnetic resonance (CE-CMR) imaging to detect and locate infarcted areas, no global study has been conducted with the aim of correlating the electrocardiographic (ECG) patterns of Q-wave MI with infarct location. We studied this correlation in 51 patients with ST-elevation acute coronary syndrome who presented with Q waves or equivalents during MI. Seven preestablished ECG patterns that matched with high specificity to 7 different MI locations as detected by CE-CMR imaging were used to assess its value in clinical practice to locate an infarcted area. There were 4 ECG patterns in the anteroseptal zone (23 patients; septal, apical, and/or anteroseptal, extensive anterior, and limited anterolateral) and 3 ECG patterns in the inferolateral zone (28 patients; lateral, inferior, and inferolateral). In conclusion, (1) the predefined ECG patterns we used matched well (86% global concordance) with their corresponding infarction areas as detected by CE-CMR imaging and have real value in clinical practice, and (2) the RS morphology in lead V(1) is due to lateral MI and the QS morphology in lead aVL is due to mid-anterior and mid-lateral MI. Therefore, the terms posterior and high lateral infarction are incorrect and should be changed to lateral wall and limited anterolateral wall MI.

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.

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.

Ventricular fibrillation is the final event in the majority of cases of sudden death. The ECG and clinical precursors of ventricular fibrillation are discussed in this article. Ventricular fibrillation usually appears as a consequence of a chain of events that leads to the appearance of this lethal arrhythmia. We review the markers of the vulnerable myocardium prone to ventricular fibrillation, the triggers and modulators that act on this vulnerable myocardium, and the event(s) that constitute the final step preceding this arrhythmia. The final step may be as unique as a sudden waterfall or present as a cascade of successive phenomena.