March 4th, 2013
New Insights on Early Repolarization
A 20-year analysis of more than 5000 participants (mean age, 25; 40% black) in the CARDIA study explores whether the early repolarization electrocardiographic pattern has multiple phenotypes. Two of the study’s authors now comment on their findings, which are published in a recent issue of the Journal of the American College of Cardiology.
Early repolarization — a finding of ST-segment elevation and J-point elevation in the absence of coronary artery disease — has been associated with young age, male sex, black race, and cardiovascular fitness. A 2008 case-control study by Haissaguerre and colleagues described higher prevalence of early repolarization among survivors of idiopathic ventricular fibrillation. Since then, several well-conducted longitudinal analyses, primarily in middle-aged white people with J-point elevation in the inferior and lateral leads (rather than the precordial leads), have confirmed increased rates of arrhythmia-related and all-cause mortality among patients with early repolarization.
The Study’s Findings
Walsh and colleagues found a definite early repolarization pattern in 18.6% of participants at baseline but in only 4.9% after 20 years. Most patients with early repolarization experienced spontaneous regression of the pattern by middle age. The baseline factors independently associated with persistence of early repolarization over time were black race, lower body-mass index, lower serum triglyceride levels, and longer QRS duration.
Analysis from the Authors
Should we now think of this ECG phenotype as a risk factor?
The commonly found precordial ST-segment elevation that occurs in younger adults is likely to regress in middle-age, and it appears to carry a benign prognosis. The previously described inferior ST-segment elevation occurring in middle-aged patients should raise suspicion for an arrhythmic substrate, particularly if accompanied by a clinical scenario of syncope or palpitations.
What should we tell patients who have early repolarization?
Patients should understand that it represents a very common electrocardiographic finding (about 19% in young adults) that is very likely to regress as they age. Our understanding of the potentially pathogenic role of early repolarization in sudden cardiac death, particularly in young adults, is too limited to discuss its prognostic implications with patients and thereby cause unnecessary anxiety. It remains unclear whether patients who maintain this pattern are at higher risk than those who do not.
Should patients be screened for early repolarization?
Our current understanding of the early repolarization pattern is too limited to enact large-scale screening or preventive efforts (even if we knew what to do for young patients with this pattern). However, in the appropriately selected population of patients with a high-enough pretest probability of sudden cardiac death (i.e., family history or a history of nonsustained ventricular tachycardia), the presence of inferior ST-segment elevation may eventually play a role in screening. This would require a more sophisticated understanding of early repolarization’s sensitivity, specificity, and predictive values for identifying an arrhythmic substrate. It would be difficult to generate a likelihood ratio sufficient to justify the cost of such a large screening effort.