Early Repolarization ECG Review

Early repolarization is a common finding in young, healthy individuals. It appears as mild ST segment elevation that can be diffuse; however, it is more prominent in the precordial leads.

The ST elevation in this setting appears like an elevated “J point.”

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It was once thought to be a benign finding, but that is no longer the case. Nonetheless, it needs to be distinguished from pathologic ST elevation that can be seen during acute myocardial infarction and pericarditis.

Note: The ECG changes of pericarditis must be distinguished from those of early repolarization. The ST elevation seen in early repolarization is very similar: diffuse and concave upward.

Two factors may help distinguish pericarditis from early repolarization:

• The ratio of the T wave amplitude to the ST elevation should be greater than 4 if early repolarization is present. In other words, the T wave in early repolarization is usually four times the amplitude of the ST elevation. Another way to describe this would be that the ST elevation is less than 25% of the T wave amplitude in early repolarization.
• The ST elevation in early repolarization resolves when the person exercises. 

Early repolarization was believed to be benign until 2008, when it was linked with sudden cardiac arrest due to idiopathic ventricular fibrillation (VF). [Macfarlane PW, et al. J Am Coll Cardiol;2015;1]

The prevalence of early repolarization is thought to be as high as 10% in some populations. [Patton KK, et al. Circulation;2016;1]

According to a consensus paper in the Journal of the American College of Cardiology, one condition for early repolarization to be present is Jp greater than or equal to 0.1 mV, with Jp being the peak of an end-QRS notch and/or the onset of an end-QRS slur, while ST-segment elevation is not a required criterion. [Macfarlane PW, et al. J Am Coll Cardiol;2015;1]

An American Heart Association scientific statement makes the following recommendations for management of patients with early repolarization: [Patton KK, et al. Circulation;2016;6b]

• Further evaluation for the incidental findings of early repolarization on an ECG in an asymptomatic patient with family history of sudden cardiac death is not recommended (Class III, level of evidence C).
• In patients with aborted sudden death or resuscitated VF who have ECG findings of early repolarization, programmed ventricular stimulation performed on the basis of an early repolarization pattern alone is not recommended (Class III, level of evidence B).
• In patients with unexplained syncope and first-degree family history of sudden death, the presence of early repolarization may be considered in overall risk stratification during appropriate evaluation for arrhythmic causes of sudden death (Class IIb, level of evidence C).

ECG Examples:

• Early Repolarization (ECG Example 1)
• Early Repolarization (ECG Example 2)

References:

• Macfarlane PW, et al. J Am Coll Cardiol. 2015;doi:10.1016/j.jacc.2015.05.033.

• Patton KK, et al. Circulation. 2016;doi:10.1161.CIR0000000000000388.