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

Predictive value of ST-segment deviation in aVR in patients suffering from acute coronary syndrome: A retrospective cohort study

Changes in the ST-segment in aVR of electrocardiogram have been used to predict the morbidity of left main and/or 3-vessel disease (LM/3-VD) in patients with acute coronary syndrome (ACS). However, the association with patient prognosis has rarely been reported. A total of 274 patients diagnosed with ACS were retrospectively evaluated following allocation into 1 of 3 groups: the ST-segment elevation (STE) group ≥ 0.05 mV, ST-segment depression (STD) group ≥ 0.05 mV, and the Isoelectric group in aVR. A comparison of clinical characteristics, coronary angiography results, major adverse cardiovascular events (MACE), and GRACE risk score was made. Patients in the STE and STD groups were older and had a lower LVEF, a greater number of MACE and higher GRACE risk score, compared with patients in the isoelectric group. Patients in the STE group had significantly greater morbidity due to LM/3-VD than did the non-STE groups. In addition, as the amplitude of STE in aVR increased, the number of MACE, GRACE risk score, and the incidence of LM/3-VD increased. Furthermore, after adjusting for other clinical factors, multivariate statistical results indicated that STE ≥ 0.05 mV in aVR was the only predictor of LM/3-VD, whereas STD ≥ 0.05 mV was not. It was found that STE or STD ≥ 0.05 mV in aVR was an independent predictor of MACE. STE ≥ 0.05 mV in aVR is associated with LM/3-VD. Furthermore, ST-segment deviation in aVR may have prognostic value of MACE and associated with higher GRACE risk scores in patients with ACS.

The predictive value of aVR in determining the infarct related artery during primary percutaneous coronary intervention

BACKGROUND

Isolation of infract related artery and timely revascularisation remains vital in the setting of primary percutaneous coronary intervention.

OBJECTIVES

To analyse the predictive value of ST-T changes in lead aVR in inferior myocardial infarction in terms of prognosis and timely risk stratification.

METHODS

We conducted a prospective analysis of acute inferior wall myocardial infarction patients. One hundred patients were categorised into two groups according to the culprit artery: group I, right coronary artery (RCA) and group II, left circumflex coronary artery (LCX), with 50 patients in each group. A comparative study was performed between the two groups, comprising the following data outputs: electrocardiogram (ECG) changes that could help determine the culprit artery, cardiac enzyme levels, echocardiographic findings, coronary angiography findings and in-hospital complications. The same patients were divided into two groups according to the presence or absence of 1 mm ST depression in lead aVR. A comparison analysis was performed between the two groups including: cardiac enzyme levels, echocardiographic findings, coronary angiography findings and in-hospital complications.

RESULTS

ST depression in aVR ≥ 1 mm predicted the LCX as a culprit artery with sensitivity, specificity, positive predictive values (PPV) and negative predictive values (NPV) recorded at 66%, 84%, 80.5% and 71.2%, respectively. Also, patients with ST depression in aVR ≥ 1 mm showed significantly higher cardiac enzyme levels, indicating larger infarct size, with mean peak creatinine kinase (CK) = 1560 (1057-2375) IU/L versus 970 (613-1683) IU/L, (P value = 0.014), lower ejection fraction (Ef) with mean Ef = 47.93 ± 8.04 versus 54.66 ± 6.52, (P value < 0.001) and more significant mitral regurgitation: 17 (41.5%) patients versus 11 (18.6%) patients (P value = 0.012). Regarding in-hospital complications, there were no significant differences.

CONCLUSIONS

ST depression of >1 mm in lead aVR predicts LCX as the infarct related artery and is a predictor of poor outcome in patients with inferior myocardial infarction.

A new electrocardiographic algorithm to locate the occlusion in left anterior descending coronary artery

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.

aVR, an index of all ECG limb leads, with clinical utility for monitoring of patients with edematous states, including heart failure

BACKGROUND

Nonreproducibility of precordial electrocardiogram (ECG) leads in serial ECGs has led to emphasis on the limb leads for some applications. Since modern electrocardiographs measure leads I and II and calculate on line the other four limb leads, the former can substitute for the set of six limb leads. Furthermore, based on the mathematical relationship of lead aVR and leads I and II, it was hypothesized that aVR could be used as a representative index of the set of the six limb leads. The aim of this study was to evaluate whether ECG lead aVR could function as an index of all limb leads, in clinical electrocardiography.

METHODS

Automation-derived and manually derived QRS voltage amplitude measurements of all limb leads in ECGs of a series of 100 randomly selected consecutive patients, and ECGs of 36 patients with various edematous states (EDST), congestive heart failure (CHF), or undergoing hemodialysis (HD), and aVR were inter-correlated with the sums of leads I and II (SigmaI&II), and the entire set of the six limb leads (Sigma6LbLds).

RESULTS

Correlation of aVR with SigmaI&II and Sigma6LbLds was excellent (P < 0.00005); also, aVR was found to be a reliable index of the six limb leads in repeat ECGs in the patients with various EDST, CHF, or undergoing HD, in whom changes in aVR correlated with changes in patients' body weight.

CONCLUSION

aVR could be taken as an index of all ECG limb leads in analysis in general, and in monitoring patients with EDST, CHF, and HD in particular.

On the use of the inverse electrocardiogram leads

This viewpoint expresses reservations about using the inverse (or negative) aVR lead in the so-called Cabrera limb lead sequence and the implementation of inverse representations of any of the other 12 standard electrocardiographic leads. Instead, the author proposes that in patients with suspected acute coronary syndromes and a nondiagnostic electrocardiographic results, electrocardiography be repeated ("double electrocardiography"), with the V1 to V6 electrodes used to record leads V3R, V4R, V7 to V9 to the left of the spine, and V9R to the right of the spine to aid in triaging patients to the appropriate management.

Right precordial leads and lead aVR at exercise electrocardiography: does it change test results?

BACKGROUND

A recent study on exercise testing (ET) suggested that ST-segment changes in the right precordial leads (RPL) may increase its sensitivity substantially. However, this study looked at a highly selected population of patients who all underwent thallium-201 scintigraphy and coronary angiography. The present study evaluated the clinical utility of ST-segment changes in the RPL and lead aVR in an unselected population of patients undergoing ET.

METHODS

A total of 906 consecutive patients who received ET were included in the study. ET was done using the Bruce Protocol with a 12-lead electrocardiogram (ECG) substituting V(4)R and V(6)R for V(1) and V(6). Leads V(1) and V(6) were selected for omission as these two leads hardly ever manifest changes in isolation. Substituting two leads would obviate the need for a more complex recording system, thus improving clinical utility.

RESULTS

On the basis of horizontal/downsloping ST-segment depression (STD) of 1.0 mm or more (the usually accepted criterion for a positive ET), 159 (17.5%) patients had a positive ET. In those patients with a negative ET (545 patients), 4 patients (0.7%) manifested STD and 5 patients (0.9%) manifested ST-segment elevation (STE) in leads V(4)R and/or V(6)R, respectively. Of note, 44.7% of the positive ET group had STE in lead aVR.

CONCLUSION

The use of ST-segment changes in RPL during exercise stress testing does not appreciably change the test results of a standard ET. If one was to consider an additional marker, STE in aVR may be more useful, as it shows a stronger correlation with positive tests and does not require the recording of additional leads.

Electrocardiographic diagnosis of the coronary artery culprit site in ischemic heart disease

The diagnostic accuracy of using electrocardiographic findings to identify affected vessels in cases of myocardial infarction and angina pectoris treated by percutaneous transluminal coronary angioplasty was assessed. From the anterior wall leads, ST segment elevation in leads I and aV(L) showed diagnostic accuracy (sensitivity, specificity and positive predictive value) in identifying proximal lesions of the left anterior descending coronary artery of 89%, 58% and 62%, and the diagnostic accuracy of the QS wave in V(1) was 62%, 83% and 72%, respectively. For the posterior wall leads, the corresponding values for the diagnosis of affected vessels based on R/S>1 in V(1) for the left circumflex coronary artery were 50%, 89% and 60%, respectively. The inferior wall leads with ST segment elevation in leads II, III and aV(F), and ST segment depression in aV(L), showed diagnostic accuracy for the right coronary artery of 90%, 90% and 92%, respectively. Bifurcation of the first diagonal branch, dominance of the posterior descending branch, the normal subtypes of the coronary artery and the occurrence of spontaneous recanalization may have influenced the accuracy of diagnosis. Adding a high lateral wall lead one intercostal space above V(4) and a posterior wall lead located one intercostal space below V(6) appeared to increase the diagnostic accuracy of detecting the coronary artery lesions responsible for myocardial ischemia.