What does early repolarization in inferior leads indicate?

From the Guidelines

Early repolarization in inferior leads on an electrocardiogram (ECG) is often a normal variant, but it may indicate an increased risk of arrhythmias, particularly in patients with a history of cardiac arrest or ventricular fibrillation, as suggested by the 2018 AHA/ACC/HRS guideline 1.

Key Points to Consider

• The early repolarization pattern is characterized by J-point elevation, notching or slurring of the terminal part of the QRS complex, and concave ST-segment elevation in leads II, III, and aVF.
• This finding is more common in males and can be lost over time, with a study showing that the pattern was lost in over 60% of young males during a 10-year follow-up 1.
• Patients with early repolarization are more susceptible to the development of ventricular fibrillation (VF) during acute cardiac ischemia and/or in the presence of QRS abnormalities due to left ventricular hypertrophy or bundle-branch block 1.
• The presence of early repolarization in patients with cardiac arrest or VF is associated with an increased risk of subsequent recurrent episodes of VF, occurring in at least 40% of patients 1.

Clinical Implications

• It is essential to distinguish benign early repolarization from more concerning conditions like acute myocardial infarction or pericarditis.
• If the pattern is new, associated with symptoms like chest pain, or appears in a patient with risk factors for heart disease, further evaluation may be warranted.
• The underlying mechanism involves differences in action potential characteristics across the ventricular wall, leading to the characteristic ECG changes.
• While most cases are benign, some research suggests that inferior lead early repolarization may occasionally be associated with a slightly increased risk of arrhythmias, though this remains controversial and doesn't typically warrant specific intervention in asymptomatic individuals 1.

From the Research

Early Repolarization in Inferior Leads

• Early repolarization in inferior leads is associated with an increased risk of death from cardiac causes 2
• The risk of death from cardiac causes is higher in individuals with J-point elevation of at least 0.1 mV in inferior leads, with an adjusted relative risk of 1.28 2
• A J-point elevation of more than 0.2 mV in inferior leads is associated with a markedly elevated risk of death from cardiac causes and from arrhythmia, with adjusted relative risks of 2.98 and 2.92, respectively 2
• Early repolarization syndrome (ERS) is characterized by an elevation of the J point and/or ST segment from the baseline by at least 0.1 mV in at least two adjoining leads, and is associated with idiopathic ventricular fibrillation (VF) and sudden death 3
• ERS is mainly observed in young men, athletes, and blacks, and the electrocardiographic territory, degree of J-point elevation, and ST-segment morphology are associated with different levels of risk for subsequent ventricular arrhythmia 3

Clinical Implications

• Early repolarization pattern is associated with ventricular fibrillation in patients with acute myocardial infarction, with a higher incidence of ER in patients with myocardial infarction complicated by VF than in patients with myocardial infarction without ventricular tachyarrhythmias 4
• The presence of early repolarization is associated with a higher incidence of recurrent ventricular fibrillation in patients with a history of idiopathic ventricular fibrillation 5
• Early repolarization syndrome is a cause of sudden cardiac death, and the risk stratification in asymptomatic patients with ERS remains a grey area 6