Early repolarization
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Overview
Early repolarization is a normal ECG variant that is most commonly seen in young males. It can be confused with ST elevation MI and pericarditis.
Definition
An example of early replzarization is shown in the figure at the top of the page. Early repolarization is defined as notching or slurring morphology of the terminal QRS complex or J-point elevation >0.1 mV above baseline in at least 2 lateral or inferior leads.[1]
Diagnosis
- Early repolarization is exacerbated by bradycardia, and carotid sinus massage may exacerbate the variant.
- The J point is frequently elevated (where the QRS joins the concave ST elevation).
Differentiating pericarditis from early repolarization
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Only lead V6 is used to distinguish the two diagnoses. As shown in the figure to the left, If A/B > 25%, suspect pericarditis. If A/B < 25%, suspect early repolarization.
Prognosis of Early Repolarization and Association with VT/VF
A case control study of 120 post MI patients with implantable cardioverter-cefibrillators (ICDs) demonstrated that early repolarization was more frequently observed among patients with documented episodes of VT/VF (32% vs. 8%, p=0.005). The leads demonstrating early repolarization were more often the inferior leads (23% vs. 8%, p=0.03). A trend was observed for the lateral leads (V4-V6) as well (12% vs. 3%, p=0.11). In contrast, leads I and aVL were not commonly involved (3% vs. 0%). The morphology of the ST segment was critical and a notch in the ST segment was observed more frequently among patients with VT/VF (28% vs. 7%, p=0.008). In contrast, J-point elevation and slurring of the ST segment surprisingly were not associated with ventricular arrhythmias.[2]