From the Guidelines
ST elevation in a single lead without reciprocal changes on an ECG is a significant finding that requires immediate clinical correlation and further evaluation to determine its cause, which may include early myocardial infarction, pericarditis, or a normal variant. When encountered, the provider should immediately assess for chest pain, shortness of breath, or other cardiac symptoms, and compare with previous ECGs if available. Additional leads (right-sided or posterior) should be considered to detect STEMI that might be missed on standard 12-lead ECG, as recommended by the American Heart Association 1. Serial ECGs at 15-30 minute intervals are recommended to monitor for evolving changes, and cardiac biomarkers (troponin) should be ordered promptly, with results ideally available within 1-2 hours 1. The isolated ST elevation may be normal in young, healthy individuals (especially Black males) as a normal variant called early repolarization, but new ST elevation in a patient with cardiac risk factors or symptoms warrants immediate cardiology consultation 1. Some key points to consider in the interpretation of ST elevation in a single lead include:
- The presence of ST-segment elevation in leads whose positive poles are located over the ischemic region, and reciprocal ST depression in leads whose positive poles are oriented in the opposite direction, is indicative of acute ischemia 1.
- The concept of subendocardial ischemia causing depression of the ST segment in multiple leads is still tenable and may be thought of as the reciprocal of endocardial ST-segment elevation caused by currents of injury directed toward the ventricular chamber 1.
- The use of additional leads, such as right-sided or posterior leads, can help detect STEMI that might be missed on standard 12-lead ECG 1.
- The importance of clinical correlation and further evaluation to determine the cause of ST elevation in a single lead, as it may represent a range of conditions from benign to life-threatening 1. Overall, the significance of ST elevation in a single lead without reciprocal changes on an ECG requires careful consideration of the clinical context and further evaluation to determine its cause and appropriate management.
From the Research
Clinical Significance of ST Elevation in One Lead
The clinical significance of ST elevation in one lead without reciprocal changes on an electrocardiogram (ECG) can be attributed to various factors.
- ST elevation is a key indicator of myocardial infarction, particularly ST-elevation myocardial infarction (STEMI) 2.
- However, ST elevation can also be caused by non-ischemic conditions, such as pericarditis or bundle branch block 3.
- A case report described an unusual finding of ST-segment elevation in one lead (V6) due to contact between the V6 electrode and a temporary pacemaker ventricular lead wire 4.
- The presence of ST elevation in one lead without reciprocal changes may not necessarily indicate ischemia at a distance or collateral circulation 5.
Differential Diagnosis
When interpreting ST elevation in one lead, it is essential to consider the differential diagnosis, including:
- Myocardial infarction with non-obstructive coronary arteries (MINOCA) 6
- Pericarditis
- Bundle branch block
- Other non-ischemic conditions 3
- Electrical phenomena, such as mirror reflection of ST-elevation 5
Diagnostic Approach
A comprehensive diagnostic approach is necessary to determine the cause of ST elevation in one lead, including: