From the Guidelines
The presence of Q waves in leads III and aVF on an ECG showing sinus rhythm, along with chest pain but negative troponin, is not automatically sufficient to warrant coronary angiography (CAG). This clinical scenario requires additional assessment, as indicated by the 2021 ESC guidelines for the management of acute coronary syndromes in patients presenting without persistent ST-segment elevation 1. A more comprehensive evaluation should include:
- Risk factor assessment (age, smoking, diabetes, hypertension, family history)
- Characterization of the chest pain (duration, quality, radiation, alleviating/aggravating factors)
- Additional non-invasive testing such as stress testing or coronary CT angiography, as recommended by the European Heart Journal study 1 The Q waves may represent old infarction or a normal variant, and without other concerning features like ST-segment changes, positive biomarkers, or high-risk clinical features, immediate CAG is not typically indicated. Management should follow a stepwise approach, starting with non-invasive risk stratification, as suggested by the Journal of the American College of Radiology study 1. If subsequent testing reveals moderate to high-risk features, or if symptoms persist despite medical therapy, then CAG would be appropriate. The decision for CAG should balance the risk of missing significant coronary artery disease against the risks of an invasive procedure.
According to the 2021 ESC guidelines, in patients with no recurrence of chest pain, normal ECG findings, and normal levels of cardiac troponin, but still with a suspected ACS, a non-invasive stress test (preferably with imaging) for inducible ischaemia or CCTA is recommended before deciding on an invasive approach 1. Additionally, the ACR appropriateness criteria suggest that arteriography is not the first-line evaluation or management in patients with low to intermediate risk, and that a noninvasive approach should be considered first 1.
Therefore, a normal ECG showing sinus rhythm with Q waves in leads III and aVF, along with chest pain and negative troponin, is not sufficient for coronary angiography, and additional non-invasive testing and risk stratification are necessary.
From the Research
Diagnostic Evaluation of Chest Pain
- The presence of a normal electrocardiogram (ECG) with sinus rhythm (SR) and Q waves in leads III and aVF, along with chest pain and negative troponin (trop), may not be sufficient for coronary angiography (CAG) 2.
- According to the study by 2, if the ECG finding is normal and results of two troponin tests are negative, risk stratification should be calculated using Thrombosis in Myocardial Infarction (TIMI) or HEART (History, ECG, Age, Risk factors, initial Troponin) score.
- The study by 3 suggests that patients with normal ECGs are at extremely low risk for acute myocardial infarction, and it may be acceptable to consider further evaluation on an outpatient basis.
- However, the study by 4 notes that new Q waves on an ECG can increase the probability of myocardial infarction, with a likelihood ratio (LR) range of 5.3-24.8.
Considerations for Coronary Angiography
- The decision to perform CAG should be based on a comprehensive evaluation of the patient's symptoms, medical history, and diagnostic test results 2, 3.
- The study by 5 highlights the importance of considering the site of infarction and the infarct-related coronary arteries when evaluating patients with acute inferior myocardial infarction.
- The use of prehospital ECG assessment and serial ECGs can contribute to the diagnosis of myocardial ischemia in chest pain patients 6.
- Ultimately, the decision to perform CAG should be made on a case-by-case basis, taking into account the individual patient's risk factors and clinical presentation 2, 3, 4.