Electrocardiographic patterns in acute inferior myocardial infarction with and without right ventricle involvement: classification, diagnostic and prognostic value, masking effect

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Agreement between actual and synthesized right-sided and posterior electrocardiographic leads in identifying ischemia

OBJECTIVE

A 12-lead electrocardiogram (ECG) is the standard of care for chest pain patients. However, 12-lead ECGs have difficulty detecting ischemia of the right ventricle or posterior wall of the heart. New technology exists to mathematically synthesize these leads from a 12-lead ECG; however, this technology has not been evaluated in the emergency department (ED). We assessed the level of agreement between synthesized 18-lead ECGs and actual 18-lead ECGs in identifying ST elevations, ST depressions, and T wave inversions in ED patients.

METHODS

Actual 12- and 18-lead ECGs were acquired and synthesized 18-lead ECGs were produced based on waveforms from 12-lead ECGs. A blinded cardiologist interpreted the actual and synthesized 18-lead ECGs to identify the presence of abnormalities. Using actual 18-lead ECGs as the reference, the sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and kappa of synthesized 18-lead ECGs in identifying abnormalities were determined.

RESULTS

Data from 295 patients were analyzed. There was 100% agreement between synthesized 18-lead ECGs and actual 18-lead ECGs in identifying ST elevations and ST depressions (sensitivity, specificity, PPV, and NPV of 100%, and kappa of 1.00). Synthesized 18-lead ECGs had 95% sensitivity, 80% specificity, 97% PPV, and 70% NPV in identifying T wave inversions, when compared with actual 18-lead ECGs (kappa: 0.70).

CONCLUSION

Synthesized 18-lead ECGs demonstrated 100% agreement with actual 18-lead ECGs in the identification of ST elevations and ST depressions and good agreement in the identification of T wave inversions in a sample of patients ED patients with complaints suspicious of cardiac origin.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Recording lead V4R is associated to enhanced use of fibrinolytic therapy in acute myocardial infarction

BACKGROUND

ST-segment elevation in the right-sided chest lead V(4)R in inferior wall myocardial infarction is recognized as a sign of proximal occlusion of the right coronary artery with evolving right ventricular myocardial infarction. Our objective is to study how often lead V(4)R is recorded in clinical practice and how this might be associated with use of reperfusion therapy and outcome of patients.

METHODS

Recording of lead V(4)R in 814 consecutive patients with acute myocardial infarction, administration of therapy, and outcome of the patients during a median follow-up of 285 days (174-313 days) were studied.

RESULTS

V(4)R was recorded in 52% of patients with inferior ST-elevation myocardial infarction. Patients with V(4)R recorded were more likely to receive fibrinolytic therapy compared with patients without recording (65% vs 51%; P = .035). In multivariate analysis, recording of lead V(4)R (odds ratio [OR] 1.6, 95% confidence interval [CI] 1.1-2.2; P = .006), along with age (P < .001), previous myocardial infarction (OR 2.2, 95% CI 1.3-3.5; P = .002), and diabetes (OR 3.9, 95% CI 1.1-2.4; P = .03) correlated to the use of reperfusion therapy. Patients with lead V(4)R recorded had less (P = .055) reinfarction, unstable angina, stroke, and/or death during follow-up.

CONCLUSIONS

Lead V(4)R was recorded in only half of patients with inferior ST-elevation myocardial infarction. Patients with V(4)R recorded were more likely to receive thrombolytic therapy than those without recording of the additional chest lead.

How many ECG leads do we need?

The number of leads needed in clinical electrocardiography depends on the clinical problem to be solved. The standard 12-lead ECG is so well established that alternative lead systems must prove their advantage through well-conducted clinical studies to achieve clinical acceptance. Certain additional leads seem to add valuable information in specific patient groups. The use of a large number of leads (eg, in body surface potential mapping) may add clinically relevant information, but it is cumbersome and its clinical advantage is yet to be proven. Reduced lead sets emulate the 12-lead ECG reasonably well and are especially advantageous in emergency situations.

Clinical Features of Emergency Electrocardiography in Patients With Acute Myocardial Infarction Caused by Left Main Trunk Obstruction

BACKGROUND

To diagnose left main trunk (LMT) infarction by 12-lead standard electrocardiogram (ECG) is an important emergency technique, but the features in LMT infarctions have not been clarified.

METHODS AND RESULTS

The study enrolled 140 subjects who were divided into 4 groups according to the location of the culprit artery: 35 with LMT, 35 with left anterior descending artery (LAD), 35 with right coronary artery and 35 with left circumflex artery. Various parameters obtained from the ECGs were analyzed. Average QTc interval (0.51 +/- 0.06 s) in LMT group was markedly longer than that in the 3 other groups. Average QRS axis (-10 +/- 77 degrees) in LMT infarction showed a remarkable left deviation. ST-segment elevation in lead aVR occurred in 28 patients (80.0%) in the LMT group. The ECG features of the LMT group could be classified into 2 main groups: right bundle branch block (RBBB) with a marked left axis deviation (RBBB + LADEV type) and ST-segment elevation in leads V2-5, I and aVL without abnormal axis deviation (LAD type).

CONCLUSION

Either ST-segment elevation in lead aVR and marked prolongation of both the QRS width and QTc interval with a prominent abnormal axis deviation or ST-segment elevation in the broad anterior precordial lead with a normal QRS axis strongly suggests LMT infarction.

Additional electrocardiographic leads in the ED chest pain patient: right ventricular and posterior leads

In the evaluation of the patient with chest pain, the 12-lead electro cardiogram is a less-than-(ECG) perfect indicator of acute myocardial infarction (AMI), particularly when used early in the course of the acute ischemic event; this relative insensitivity for AMI results from many different issues, including a less-than-optimal imaging of certain areas of the heart. It has been suggested that the sensitivity of the 12-lead ECG can be improved if 3 additional body surface leads are used in selected individuals. Acute posterior (PMI) and right ventricular myocardial infarctions are likely to be underdiagnosed, because the standard lead placement of the 12-lead ECG does not allow these areas to be assessed directly. Additional leads frequently used include leads V(8) and V(9), which image the posterior wall of the left ventricle, and lead V(4R), which reflects the status of the right ventricle. The standard ECG coupled with these additional leads constitutes the 15-lead ECG, the most frequently used additional lead ECG in clinical practice. The use of the additional leads might not only confirm the presence of AMI, but also provide a more accurate reflection of the true extent of myocardial damage.

ECG discrimination between right and left circumflex coronary arterial occlusion in patients with acute inferior myocardial infarction: value of old criteria and use of lead aVR

STUDY OBJECTIVES

Prior studies have proposed several ECG criteria for identifying the culprit artery in patients with acute inferior myocardial infarction (MI). We applied each criterion to our patients to assess its utility. In doing so, we discovered a previously unreported, but highly useful, criterion utilizing lead aVR.

STUDY DESIGN

Retrospective review.

PATIENTS

Thirty consecutive patients with symptoms of acute MI, ST-segment elevation in the inferior ECG leads, an appropriate rise and fall of creatine kinase and troponin I levels, and coronary arteriography within 7 days of the onset of symptoms.

MEASUREMENTS

The ECG recorded within 24 h of the onset of symptoms that had the most prominent ST-segment changes was analyzed. In the 12 standard leads and in lead V(4)R, ST-segment elevation or depression was measured 0.06 s after the J point.

RESULTS

Four previously described criteria were useful in identifying the right coronary artery (RCA) or the left circumflex coronary artery (LCX) as the culprit: ST-segment elevation in lead I, ST-segment more or less elevated in lead II than in lead III, ST-segment elevation >or= 0.5 mm in lead V(4)R, and various combinations of ST-segment elevation or depression in leads V(1) and V(2). A new criterion was found to be at least as useful as any previously described: the presence and amount of ST-segment depression in lead aVR.

CONCLUSIONS

At least five different ST-segment criteria help to identify the RCA or the LCX as the culprit artery in patients with acute inferior MI. One of these, the amount of ST-segment depression in lead aVR, has not been reported previously and needs validation in a larger study.

Characteristics of presenting electrocardiograms of acute myocardial infarction from a community-based population predict short- and long-term mortality

To investigate the relevance of presenting electrocardiographic (ECG) patterns to short- and long-term mortality in nonreferral patients with acute myocardial infarction (AMI), 6 ECG patterns were analyzed. A consecutive series of 907 patients from Olmsted County, Minnesota, admitted to the Mayo Clinic Cardiac Care Unit from January 1, 1988 to March 31, 1998 for acute myocardial infarction comprised the study population. ECG patterns and distribution in the population were: (1) ST elevation alone (20.8%), (2) ST elevation with ST depression (35.2%), (3) normal or nondiagnostic electrocardiograms (18.5%), (4) ST depression alone (11.8%), (5) T-wave inversion only (10.7%), and (6) new left bundle branch block (LBBB) (3.0%). Seven- and 28-day mortalities varied significantly (p <0.01) among the 6 ECG groups. Respective mortalities were 3.0% and 6.0% for patients with normal or nondiagnostic electrocardiograms, 3.1% and 5.2% for T-wave inversion only, 7.4% and 10.6% for ST elevation alone, 9.4% and 13.1% for ST depression alone, 10.3% and 13.8% for ST elevation with ST depression, and 18.5% and 22.2% for new LBBB. Length of hospital stay (LOS) also varied among the ECG pattern groups (p <0.001) with the longest average LOS being in the new LBBB group (12.5 days). Long-term survival was similar among 5 ECG pattern groups (45% to 55% at 8 years from discharge) with the exception of LBBB (20% at 8 years). Among non-LBBB groups, ST-segment depression with or without ST elevation was associated with increased short-term mortality. Also, in this community-based population, 18.5% of patients had normal or nondiagnostic electrocardiograms.

Right ventricular infarction mimicking anterior infarction: a case report

Right ventricular infarction usually occurs in association with inferior infarction, with no remarkable electrocardiographic signs in conventional leads. This report describes a patient with a previous inferior acute myocardial infarction who developed right ventricular infarction with significant anterior lead ST segment elevation (V1-V4) caused by the loss of two large right ventricular branches during a coronary angioplasty of the right coronary artery. The case is discussed and the literature is reviewed.