From the Guidelines
Normal variant ST elevation is a benign electrocardiographic finding that does not indicate myocardial injury or ischemia, and no specific treatment is required. This pattern is characterized by ST segment elevation, often with notching or slurring of the J point, and is most commonly seen in young adults, athletes, males, and individuals of African descent 1. The significance of normal variant ST elevation lies in its distinction from pathologic ST elevation seen in conditions like acute myocardial infarction, pericarditis, or Brugada syndrome. Key differentiating features include:
- Absence of reciprocal ST depression
- Lack of concerning symptoms (chest pain, shortness of breath)
- Stable pattern over time
- Normalization with exercise According to the American Heart Association, early repolarization is defined as "a normal variant commonly characterized by J-point elevation and rapidly upsloping or normal ST segment" 1. The physiologic basis for early repolarization involves variations in potassium channel function in the epicardium versus endocardium, creating transmural voltage gradients during repolarization that manifest as ST elevation on the surface ECG. It is essential to standardize the definitions of early repolarization to avoid confusion and ensure accurate diagnosis and treatment 1.
Some key points to consider when interpreting normal variant ST elevation include:
- The magnitude and duration of the J-point elevation
- The elevation of the ST segment
- Concomitant electrocardiographic findings such as J-wave augmentation or short coupled premature ventricular contractions
- The character of the QRS complex and J point (notching or slurring) In clinical practice, it is crucial to recognize normal variant ST elevation as a benign finding to avoid unnecessary testing, treatment, and anxiety for patients 1.
From the Research
Significance of Normal Variant ST Elevation
The significance of normal variant ST elevation in an electrocardiogram (ECG) is a topic of interest in the medical field, particularly in relation to distinguishing it from ST-elevation myocardial infarction (STEMI) and other cardiac conditions.
- Normal variant ST elevation, also known as early repolarization, can be difficult to differentiate from subtle ischemic ST elevation due to left anterior descending (LAD) occlusion 2.
- A study proposed a simplified formula to discriminate subtle anterior wall myocardial infarction from normal variant ST-segment elevation, which was found to be noninferior to existing formulas 3.
- The formula, which takes into account the R-wave amplitude in lead V4, QRS amplitude in V2, QT interval, and ST elevation at 60 ms after the J-point in lead V3, was found to have an excellent area under the curve (AUC) of 0.963 3.
- Another study derived a 4-variable formula that adds QRS voltage in V2 to improve the accuracy of differentiating subtle LAD occlusion from normal variant ST elevation, with an AUC of 0.9686 2.
- Normal variant ST elevation can also be seen in other conditions, such as hypertrophic cardiomyopathy, where it may simulate other ST segment elevation syndromes, including acute myocardial infarction and pericarditis 4.
- A clinical review highlighted the importance of considering conditions where ST-segment elevation is accompanied by no atherosclerotic lesion on coronary angiography, including anomalous coronaries and anatomically normal coronaries with varied degrees of myocardial injury 5.
- A case study of a 22-year-old male with myocarditis, which was initially suspected to be STEMI, highlighted the challenges of clinical diagnosis and the importance of a high index of suspicion and prompt diagnosis to prevent delays in appropriate therapy 6.