ECG Review

Early Repolarization with Artifact

By Ken Grauer, MD, Professor, Assistant Director, Family Practice Program, University of Florida. Dr. Grauer reports no financial relationship to this field of study.

Figure. 12-lead ECG obtained from a middle-aged man with atypical chest discomfort.

Clinical Scenario: The ECG in the Figure was obtained from a previously healthy, middle-aged man with some atypical but new-onset chest discomfort. This ECG was obtained at the time the patient arrived in the ED (Emergency Department), and was interpreted as "normal, with ST-T wave changes of early repolarization." Do you agree? Clinically, what would you do?

Interpretation/Answer: The ECG shows normal sinus rhythm at a rate of 80/minute. There is baseline artifact for several of the complexes seen in lead V2, but this does not prevent overall assessment of the tracing. All intervals and the mean QRS axis are normal. There is no ECG evidence of chamber enlargement. A Q wave is seen in lead aVL. Transition occurs normally (between leads V2 to V3) in the precordial leads. The most remarkable finding on this tracing lies with interpretation of the ST-T wave. ST segment coving of uncertain significance is seen in the inferior leads. Although this could represent the beginning of an acute change (especially in the context of the Q wave and slight T wave inversion in lead aVL) — by itself it is nondiagnostic.

The most concerning finding on the tracing is the T wave appearance in the anterior precordial leads. T waves are unexpectedly tall and quite peaked in leads V1, V2, and V3. Although this could represent a normal variant pattern of early repolarization, that interpretation should always be left as a diagnosis of exclusion. Hyperkalemia is unlikely in this case because of the patient's history, the fact that T wave peaking is limited to only several leads, and that the base of the T wave in leads with peaking is wider than usually seen with hyperkalemia. Obtaining serum electrolytes would resolve this question.

The patient in this case underwent cardiac catheterization and was found to have acute occlusion of the circumflex coronary artery. The point to emphasize is that the occurrence of disproportionately tall, peaked T waves in several leads of a 12-lead tracing in association with new-onset chest discomfort may sometimes be the ECG manifestation of acute coronary ischemia.