From the Guidelines
An inferior ECG strain pattern is a significant electrocardiographic finding that implies increased workload or stress on the inferior wall of the left ventricle, typically indicating underlying conditions such as left ventricular hypertrophy, myocardial ischemia, or valvular heart disease. This pattern is characterized by ST segment depression and T wave inversion in the inferior leads (II, III, and aVF) of an electrocardiogram. According to the most recent guidelines, when seen in the context of chest pain, it raises concern for acute coronary syndrome involving the right coronary artery territory 1. The physiological basis for this pattern involves abnormal repolarization of cardiac myocytes due to increased wall stress, oxygen demand-supply mismatch, or altered electrical conduction.
Some key points to consider when interpreting an inferior ECG strain pattern include:
- The presence of ST-segment elevation in leads II, III, and aVF may indicate occlusion of the right coronary artery (RCA) or the left circumflex coronary artery (LCx) 1
- The spatial vector of the ST segment can help distinguish between RCA and LCx occlusion, with RCA occlusion typically resulting in greater ST-segment elevation in lead III than in lead II 1
- Right-sided chest leads (VR and V4R) can be useful in diagnosing right ventricular involvement in the setting of an inferior wall infarction and in making the distinction between RCA and LCx occlusion 1
In terms of management, patients with an inferior ECG strain pattern should undergo further cardiac evaluation, including:
- Assessment of cardiac enzymes
- Additional ECG monitoring
- Possibly cardiac imaging studies like echocardiography or stress testing to determine the specific cause and appropriate treatment strategy 1 It is essential to note that a completely normal ECG in a patient with chest pain does not exclude the possibility of acute coronary syndrome, and further evaluation is necessary to determine the underlying cause of the symptoms 1.
From the Research
Definition of Inferior ECG Strain Pattern
- The inferior ECG strain pattern is characterized by ST-segment depression and T-wave inversion in the inferior leads (II, III, and aVF) of an electrocardiogram (ECG) 2.
- This pattern is often associated with left ventricular hypertrophy (LVH) and is considered a marker of adverse prognosis in population studies 2.
Implications of Inferior ECG Strain Pattern
- The presence of an inferior ECG strain pattern is a significant predictor of cardiovascular mortality, myocardial infarction, and stroke, even after adjusting for standard cardiovascular risk factors and baseline blood pressure 2.
- In patients with suspected coronary artery disease, an abnormal or indeterminate stress ECG, including inferior lead changes, may indicate the presence of obstructive CAD despite normal imaging results and predict an increased likelihood of coronary revascularization 3.
- The correlation between electrocardiographic changes, including inferior lead changes, and coronary findings in patients with acute myocardial infarction and single-vessel disease has been investigated, with results suggesting that inferior STEMI is highly likely to be associated with right coronary artery (RCA) or left circumflex artery (LCX) obstructive CAD 4.
Clinical Significance
- The inferior ECG strain pattern is an important marker of increased cardiovascular risk and should be considered in the diagnosis and management of patients with hypertension and suspected coronary artery disease 2, 3.
- Clinicians should be aware of the potential for ECG changes, including inferior lead changes, to mimic acute myocardial infarction, and comprehensive clinical examination and medical history are crucial for making the correct diagnosis 5.