Significance of exercise-induced ST changes in leads aVR, V5, and V1. Discrimination of patients with single- or multivessel coronary artery disease

Lead aVR predicts early revascularization but not long-term events in patients referred for stress electrocardiography

BACKGROUND

Exercise stress electrocardiography (ExECG) is recommended as a first-line tool to assess ischemia, but standard ST-analysis has limited diagnostic accuracy. ST elevation in lead aVR has been associated with left main and LAD disease in the population undergoing coronary angiography but has not been studied in the general population undergoing stress testing for the initial evaluation of CAD without coronary angiography. We sought to determine the predictive value of lead aVR elevation for ischemia, early revascularization, and subsequent cardiac events in consecutive patients undergoing ExECG.

METHODS AND RESULTS

The study cohort included 641 subjects referred for ExECG who were dichotomized by presence or absence of aVR elevation ≥1mm and compared for prevalence and predictors of ischemia and a composite of cardiac death, nonfatal myocardial infarction, and late revascularization. The cohort had a median age of 57 and 57% were male. The prevalence of aVR elevation was 11.5%. The prevalence of significant ischemia on patients who received imaging was significantly higher with aVR elevation (14.3% vs 2.3%, p<0.001). Early revascularization occurred in 10.9% with vs 0.2% without aVR elevation, p<0.001. No subjects without aVR elevation or ST-depression underwent early revascularization. However, cardiac event rates were similar over a median 4.0 years of follow-up with and without aVR elevation (2.8% vs. 2.6%, p = 0.80). aVR elevation did not predict long-term cardiac events by Kaplan-Meier survival analysis (p = 0.94) or Cox proportional hazards modeling (p = 0.35).

CONCLUSIONS

aVR elevation during ExECG predicts ischemia on imaging and early revascularization but not long-term outcomes and could serve as a useful adjunct to standard ST-analysis and potentially reduce the need for concurrent imaging.

Is isolated ST segment elevation in Lead aVR associated with high grade coronary artery disease?

BACKGROUND

The diagnostic accuracy of lead aVR ST-segment elevation for left main or triple vessel disease (LM/3VD) has not been universally accepted. In the present analysis we sought to evaluate the diagnostic accuracy of STEaVR in patients presenting with an acute coronary syndrome (ACS).

METHODS

Pooled sensitivity, specificity, positive, and negative likelihood ratios were calculated using a random effects model (DerSimonian-Laird Method) for computing summary estimates and receiver operator curve (ROC) analysis for evaluating overall diagnostic accuracy.

RESULTS

This meta-analysis included 14 studies. The pooled sensitivity of STEaVR for LM/3VD was 0.40 (95% CI; 0.38 0.43, p < 0.001), specificity 0.82 (95% CI; 0.81-0.83, p < 0.001). Pooled positive likelihood ratio 2.49 (95% CI; 1.62-3.81, p < 0.001) and negative likelihood 0.54 (95% CI; 0.39-0.76, p < 0.001). The pooled sensitivity of STEaVR for LM was 0.39 (95% CI; 0.34-0.45, p < 0.001) specificity was 0.86 (95% CI; 0.85-0.87, p < 0.001) with an AUC of 0.79. The pooled positive likelihood ratio (LR) for LM was 2.78 (95% CI, 2.28-3.39, p < 0.001) negative likelihood ratio 0.51 (95% CI, 0.33-0.78, p < 0.001).

CONCLUSION

Our study shows that in patients presenting with an ACS, presence of STEaVR may indicate the presence of LM or 3VD. STEaVR has a high specificity for both LM and 3VD, with a high pooled LR.

Electrocardiographic changes in patients with acute myocardial infarction caused by left main trunk occlusion

BACKGROUND

Left main trunk (LMT) occlusion is a rare angiographic finding. The primary purpose was to investigate the ECG pattern of patients with angiographic confirmation of LMT as culprit lesion.

METHODS

Forty-eight patients (32 men; mean age 73 years) with angiographic total (21 patients; 44%) or subtotal (27 patients; 56%) occlusion of the LMT were analyzed. Twenty patients (42%) were found to have concomitant coronary lesions. Eighteen patients (38%) required intra-aortic balloon pump support.

RESULTS

A significant left axis deviation was observed in 26 cases (54%) and an intraventricular conduction delay in 32 patients (67%). The average QRS width and QTc interval were 122 and 433 ms, respectively. ST-segment elevation in lead aVR occurred in 32 patients (67%). ST-segment elevation in leads V2-5 and in leads I and aVL [classic left anterior descending (LAD) type] was frequently observed (18 cases; 35%). In six patients (13%), a partial LAD type was observed with ST-segment elevation in leads I and aVL, but not in peripheral leads. The remaining patients showed ST-segment elevation only in peripheral leads (12 cases), in inferior leads III + aVF (six cases), whereas six patients had no ST-segment elevation. Diffuse ST-segment depression only (>6 leads) was observed in 15 cases (31%). Eighteen patients (38%) died during hospitalization.

CONCLUSION

ST-segment elevation in lead aVR or a LAD-type pattern can be associated with LMT disease. Other relevant aspects are the presence of cardiogenic shock at admission, the left axis deviation and marked prolongation of QTc interval and QRS width.

Diagnostic and Prognostic Value of Lead aVR During Exercise Testing in Patients Suspected of Having Myocardial Ischemia

We aimed to assess the diagnostic and prognostic value of ST-segment deviation in aVR, a lead often ignored in clinical practice, during exercise testing and to compare it to the most widely used criterion of ST-segment depression in V₅. We enrolled 1,596 patients with suspected myocardial ischemia referred for nuclear perfusion imaging undergoing bicycle stress testing. ST-segment amplitudes in leads aVR and V₅ were automatically measured. The presence of inducible myocardial ischemia was the diagnostic end point and adjudicated based on nuclear perfusion imaging and coronary angiography. Major adverse cardiac events (MACE) during 2 years of follow-up including death, acute myocardial infarction, and coronary revascularization were the prognostic end point. Exercise-induced myocardial ischemia was detected in 470 patients (29%). Median ST amplitudes for leads aVR and V₅ differed significantly among patients with and without ischemia (p <0.01). The diagnostic accuracy of ST changes for myocardial ischemia as quantified by the area under the receiver operating characteristic curve was highest 2 minutes into recovery and similar in aVR and V₅ (0.62, 95% confidence interval CI 0.60 to 0.65 vs 0.60, 95% confidence interval 0.58 to 0.63, p = 0.08 for comparison). In multivariate analysis, ST changes in lead aVR, but not lead V₅, contributed independent diagnostic information on top of clinical parameters and manual electrocardiographic interpretation. Within 2 years of follow-up, MACE occurred in 33% of patients with ST elevations in aVR and in 16% without (p <0.001). In conclusion, ST elevation in lead aVR during exercise testing indicates inducible myocardial ischemia independently of ST depressions in lead V₅ and clinical factors and also predicts MACE during follow-up.

Predictive Value of Exercise Stress Test-Induced ST-Segment Changes in Leads V1 and avR in Determining Angiographic Coronary Involvement

BACKGROUND

The significance of electrocardiographic changes during exercise tolerance testing for distinguishing occluded artery is not well known. We tried to determine the role of ST elevation in leads aVR and V₁ during exercise in detecting stenosis of left main coronary artery and proximal left anterior descending artery.

METHODS

ST segment changes during exercise in 230 patients, who underwent diagnostic angiography, were documented. The association of ST elevation in lead aVR, V₁ , leads aVR + V₁ , and STE in leads aVR + V₁ with ST depression in other leads with pattern of coronary stenosis were investigated.

RESULTS

Left main and proximal left anterior artery stenosis were more common in patients with ST elevation in lead aVR (P < 0.001 for both). Similar association was found in the presence of ST elevation in lead V₁ . The presence of ST elevation ≥1 mm in lead aVR had a sensitivity of 100% and 94.3% for detecting left main and left anterior descending artery stenosis, respectively. The specificity was 33.5% and 26.6%, respectively. ST elevation in leads aVR + V₁ had a sensitivity of 74.4% and 65.9% and a specificity of 68.5% and 64.4% for detecting left main and left anterior descending arteries stenosis, respectively.

CONCLUSION

ST elevation in lead aVR is highly sensitive for left main and proximal left anterior descending artery lesions. Using ST elevation in lead V₁ in addition to lead aVR as a positive finding increases the specificity with a further decrease in sensitivity.

Classical electrocardiographic clues for left main coronary artery disease

Prediction of left main coronary artery (LMCA) or equivalent disease is important with regard to selecting the appropriate treatment strategy. The classical electrocardiographic pattern of LMCA disease includes ST elevation (STE) in lead aVR in the presence of extensive ST depression (most prominent in leads I, II, and V4–6) with the STE in aVR ≥ V1. Patients with these findings may potentially require early coronary angiography and coronary bypass surgery; therefore selected patients with these findings on exercise testing might benefit from more urgent or expedited angiography.

Clinical value of lead aVR

Lead aVR is the only lead in the surface ECG that does not face the "typically" relevant walls of the left ventricle. Historically, its value has been neglected most likely due to its unusual configuration and direction, which appeared to have little correlation with other more congruous and easily diagnostic frontal leads. The isolation of the unipolar leads in the Standard surface ECG presentation may also have played an important role. Even with this "unfair" neglect, we know nowadays that it is very sensitive to locate obstructed epicardial coronary arteries. Besides helping distinguishing the culprit lesion of an infarct, lead aVR also helps recognizing other conditions that could be of clinical significance such as pericarditis, Brugada syndrome, fascicular blocks of the right branch, ectopic left atrial rhythms, etc. The purpose of this review is to revise the clinical value of lead aVR in the recognition of frequent and not so frequent clinical conditions.

Clinical utility of aVR-The neglected electrocardiographic lead

BACKGROUND

Several studies suggest that electrocardiographers tend to neglect lead aVR during the reading of electrocardiograms (ECGs). Our objective was to provide a systematic review of the most important diagnostic and prognostic uses of lead aVR.

METHODS

We performed a thorough review of the literature about the lead aVR using PubMed, MEDLINE and the archives of the University at Buffalo libraries.

RESULTS

We found that lead aVR may provide important additional information in the diagnosis of coronary artery disease. It may provide a clue to the location of a lesion as well as the possibility of three vessel disease during an acute coronary syndrome. Lead aVR was found useful in the locus of arrhythmias and in differentiation of narrow and wide QRS complex tachycardias. It provides useful prognostic information for patients with the Brugada syndrome and tricyclic antidepressant toxicity. Lead aVR provides alternative criteria for the electrocardiographic diagnosis of left ventricular hypertrophy and left anterior fascicular block.

CONCLUSION

Lead aVR provides very important additional diagnostic and prognostic information in multiple cardiac conditions and can be used either alone or in conjunction with other electrocardiographic leads.

ST segment elevation in lead aVR during exercise testing is associated with LAD stenosis

PURPOSE

To evaluate, in patients with chest pain, the diagnostic value of ST elevation (STE) in lead aVR during stress testing prior to (99m) Tc-sestamibi scanning correlating ischaemic territory with angiographic findings.

METHODS

Consecutive patients attending for (99m) Tc-sestamibi myocardial perfusion imaging (MPI) completed a treadmill protocol. Peak exercise ECGs were coded. STE >or=0.05 mV in lead aVR was considered significant. Gated perfusion images and findings at angiography were assessed.

RESULTS

STE in lead aVR occurred in 25% (138/557) of the patients. More patients with STE in aVR had a reversible defect on imaging compared with those who had no STE in aVR (41%, 56/138 vs 27%, 114/419, p=0.003). Defects indicating a left anterior descending artery (LAD) culprit lesion were more common in the STE in aVR group (20%, 27/138 vs 9%, 39/419, p=0.001). There was a trend towards coronary artery stenosis (>70%) in a double vessel distribution involving the LAD in those patients who had STE in aVR compared with those who did not (22%, 8/37 vs 5%, 4/77, p=0.06). Logistic regression analysis demonstrated that STE in aVR (OR 1.36, p=0.233) is not an independent predictor of inducible abnormality when adjusted for STD >0.1 mV (OR 1.69, p=0.026). However, using anterior wall defect as an end-point, STE in aVR (OR 2.77, p=0.008) was a predictor even after adjustment for STD (OR 1.43, p=0.281).

CONCLUSION

STE in lead aVR during exercise does not diagnose more inducible abnormalities than STD alone. However, unlike STD, which is not predictive of a territory of ischaemia, STE in aVR may indicate an anterior wall defect.