Curriculum in CardiologyElectrocardiographic diagnosis of acute myocardial infarction: Current concepts for the clinician☆
Section snippets
Normal anatomic references
Several anatomic caveats are pertinent to the assessment of new fascicular blocks or axis changes and to the assessment of infarct location.
The heart lies horizontally with the atria at its base and the ventricles at its apex.4 Because the heart is rotated over its long axis, the right atrium and ventricle are more anterior than the left chambers, and the right and left sides of the heart are not aligned with the same sides of the body. Thus the interventricular septum is almost parallel with
Value of ST-segment elevation
The electrocardiograms that give us the most concern in emergency departments are those with a large amount of ST-segment deviation. The initial ST-segment sum is the main variable influencing “door to thrombolysis” time; the largest ST deviations result in the shortest times to treatment.11 Although this is usually justified, many factors such as myocardial mass, distance between the electrodes and the ischemic zone, and reciprocal “cancellation” changes may affect the magnitude of ST
Electrocardiographic-angiographic correlations revisited
The most frequent infarct-related artery among patients admitted with chest pain or discharged from the hospital after AMI is the LAD (44% to 56% of cases), followed by the RCA (27% to 39%) and the LCX (17%).13
Anterior plus inferior injury
The combination of anterior and inferior ST elevation in the electrocardiogram may give the impression of a critical mass of myocardial injury. However, it often results from distal occlusion of a long LAD, which “wraps around” the cardiac apex and results in wall motion abnormalities circumscribed to the cardiac apex.37 When injury in leads II, III, and aVF is accompanied by ST elevation in V1 but ST depression in V2, right ventricular—rather than apical—infarction is likely.38
Septal infarction
The ST elevation
ST-segment depression
Many patients with acute chest pain have “reciprocal” ST-segment depression, that is, ST-segment depression concomitant with ST-segment elevation in a lead group different than the one showing ST elevation. The mechanism underlying this ST depression is usually mirroring, a phenomenon of electrical reflection of the transmural injury onto the opposite ventricular wall. The ST depression is captured by a lead placed at 180 degrees of the lead recording the ST elevation, although the terms
Bundle branch block/ventricular pacing
Inclusion criteria for patients with chest pain in many clinical studies and registries require grouping patients with either RBBB or LBBB into a common category of “difficult” or “impossible” early diagnoses.57 However, the diagnosis of AMI in patients with RBBB is rarely obscured by the conduction defect. Myocardial injury should not be missed more often in these patients than in those with normal conduction because ST-segment elevation in both anterior and inferior injury (as well as
Pseudoinfarction patterns
Several conditions mimic AMI and may pose a diagnostic challenge.
Nondiagnostic electrocardiograms
Fifteen percent to 18% of patients with AMI do not show changes in the initial electrocardiogram, and an additional 25% show nonspecific changes.2 Although nondiagnostic electrocardiograms in patients with chest pain are often associated with lesions in branch vessels, the probability of detecting AMI does increase by recording serial electrocardiograms.76 However, because reperfusion therapies are more effective when administered early, it is ideal to maximize the information provided by the
Conclusions and recommendations
Relative to other diagnostic methods in cardiology, electrocardiographic technology has lagged behind. Experts in electrocardiography have called for a concerted effort to incorporate modern features to the bedside diagnosis such as high-resolution, additional leads and 3D vectrocardiography imaging.78 These additions would improve our ability to diagnose AMI.
In the meantime, however, the plethora of data currently available on electrocardiographic changes accompanying chest pain should allow
References (78)
- et al.
Interindividual variability of multilead electrocardiographic recordings: influence of heart position
J Electrocardiol
(1999) - et al.
The standard 11-lead ECG: neglect of lead aVR in the classical limb lead display
J Electrocardiol
(1996) - et al.
Panoramic display of the orderly sequenced 12-lead ECG
J Electrocardiol
(1994) - et al.
Location of myocardial infarcts: a confusion of terms and definitions
Am J Cardiol
(1978) - et al.
Left ventricular asynergy in electrocardiographic “posterior” myocardial infarction
J Am Coll Cardiol
(1984) - et al.
Impact of the electrocardiogram on the delivery of thrombolytic therapy for acute myocardial infarction
Am J Cardiol
(1994) - et al.
Electrocardiographic and coronary correlations during acute myocardial infarction
Am J Cardiol
(1984) - et al.
Identification of optimal electrocardiographic leads for detecting acute epicardial injury in acute myocardial infarction
Am J Cardiol
(1987) - et al.
Prediction of the level of left anterior descending coronary artery obstruction during anterior wall acute myocardial infarction by the admission electrocardiogram
Am J Cardiol
(1993) - et al.
Clinical significance of the disappearance of septal Q waves after the onset of myocardial infarction: correlation with location of responsible coronary lesions
J Electrocardiol
(1999)
Value of the electrocardiogram in localizing the occlusion site in the left anterior descending coronary artery in acute myocardial infarction
J Am Coll Cardiol
Ventricular excitation during percutaneous transluminal angioplasty of the left anterior descending coronary artery
Am J Cardiol
Importance of the conal branch of the right coronary artery in patients with acute anterior wall myocardial infarction: electrocardiographic and angiographic correlation
J Am Coll Cardiol
ST elevations in leads V1 to V5 may be caused by right coronary artery occlusion and acute right ventricular infarction
Am J Cardiol
Isolated midanterior myocardial infarction: a special electrocardiographic sub-type of acute myocardial infarction consisting of ST-elevation in nonconsecutive leads and two different morphologic types of ST-depression
Int J Cardiol
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
Am Heart J
Value of lead V4R for recognition of the infarct coronary in acute inferior myocardial infarction
Am J Cardiol
New electrocardiographic criteria for predicting either the right or left circumflex artery as the culprit coronary artery in inferior wall acute myocardial infarction
Am J Cardiol
Usefulness of ST-segment elevation in lead III exceeding that of lead II for identifying the location of the totally occluded coronary artery in inferior wall myocardial infarction
Am J Cardiol
Comparison of patients with inferior wall acute myocardial infarction with versus without ST-segment elevation in leads V5 and V6
Am J Cardiol
New electrocardiographic criteria for predicting the site of coronary artery occlusion in inferior wall acute myocardial infarction
Am J Cardiol
Significance of ST segment elevations in posterior chest leads (V7 to V9) in patients with acute inferior myocardial infarction: application for thrombolytic therapy
J Am Coll Cardiol
A comprehensive analysis of myocardial infarction due to left circumflex artery occlusion: comparison with infarction due to right coronary artery and left posterior descending artery occlusion
J Am Coll Cardiol
. Electrocardiographic evolution of posterior myocardial infarction: importance of early precordial ST-depression
Am J Cardiol
Implications of inferior ST-segment elevation accompanying anterior wall acute myocardial infarction for the angiographic morphology of the left anterior de-scending coronary artery morphology and site of occlusion
Am J Cardiol
Simultaneous ST-segment elevation in lead V1 and depression in lead V2: a discordant ECG pattern indicating right ventricular infarction
J Electrocardiol
Does the electrocardiographic pattern of “anteroseptal” myocardial infarction correlate with the anatomic location of myocardial injury?
Am J Cardiol
Inferoseptal myocardial infarction: another cause of precordial ST-segment depression in transmural inferior wall myocardial infarction?
Am J Cardiol
Value of the electrocardiogram in diagnosing the number of severely narrowed coronary arteries in rest angina pectoris
Am J Cardiol
Right ventricular involvement with acute inferior wall myocardial infarction identifies high risk of developing atrioventricular nodal conduction disturbances
Am Heart J
Electrocardiographic findings in acute right ventricular infarction: sensitivity and specificity of electrocardiographic alterations in right precordial leads V4R, V3R, Vl, V2, and V3
J Am Coll Cardiol
Right ventricular myocardial infarction in patients with chronic lung disease: possible role of right ventricular hypertrophy
J Am Coll Cardiol
Reciprocal ST change in acute myocardial infarction: assessment by electrocardiography and echocardiography
J Am Coll Cardiol
Are reciprocal changes a consequence of “ischemia at a distance” or merely a benign electric phenomenon? A PTCA study
Am Heart J
Patients with suspected myocardial infarction who present with ST depression
Lancet
Correlation of angiographic findings and right (V1 to V3) versus left (V4 to V6) precordial ST-segment depression in inferior wall acute myocardial infarction
Am J Cardiol
Do patients with left circumflex coronary artery-related acute myocardial infarction without ST-segment elevation benefit from reperfusion therapy?
Am J Cardiol
Electrocardiographic differentiation of the ST-segment depression of acute myocardial injury due to the left circumflex artery occlusion from that of myocardial ischemia of nonocclusive etiologies
Am J Cardiol
Late assessment of thrombolytic efficacy (LATE) study: prognosis in patients with non-Q wave myocardial infarction
J Am Coll Cardiol
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Deep learning model to detect significant aortic regurgitation using electrocardiography
2022, Journal of CardiologyCitation Excerpt :Raw data from each ECG examination record were represented as a 5,000 × 12 matrix of ECG voltages, in which the first dimension was the temporal dimension (each row represented a specific time point) and the second dimension was the spatial dimension (each column represented one lead) [14]. Therefore, to emphasize the spatial information, we rearranged the leads as follows: II, III, aVF, I, aVL, V6, aVR, V1, V2, V3, V4, and V5 [15]. Before training models, the training and validation datasets were augmented.
Guía ESC 2015 sobre el tratamiento de los síndromes coronarios agudos en pacientes sin elevación persistente del segmento ST: Grupo de Trabajo de la Sociedad Europea de Cardiología (ESC) para el tratamiento de los síndromes coronarios agudos en pacientes sin elevación persistente del segmento ST
2015, Revista Espanola de CardiologiaTrends in myocardial infarction rates and case fatality by anatomical location in four united states communities, 1987 to 2008 (from the atherosclerosis risk in communities study)
2013, American Journal of CardiologyCitation Excerpt :Anterior STEMI was defined as an ST-segment elevation of ≥2.0 mm in any of the leads V1 to V4 or an ST-segment elevation of ≥1.0 mm in V5; inferior STEMI as an ST-segment elevation of ≥1.0 mm in any of the leads II, III, or aVF; and lateral STEMI as an ST-segment elevation of ≥1.0 mm in any of the leads I, aVL, and V6 alone or in the presence of anterior ST-segment elevations.16 ST elevations in the anterior and lateral electrocardiographic lead groups were combined to increase sensitivity to detect lateral STEMI, as ischemia of the lateral wall may be poorly represented by the lateral leads (I, aVL, and V6) alone.17,18 Finally, to represent ischemia in multiple anatomic locations, a multilocation STEMI was defined as ST-segment elevations in ≥2 of anterior, inferior, or lateral locations.
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Reprint requests: Elena B. Sgarbossa, MD, Cardiology, Rush Presbyterian-St Luke’s Medical Center, 1750 W Harrison St, Chicago, IL 60612. E-mail: [email protected]