Abstract 16709: Heritability of Early Repolarization - a Population-Based Study
The electrocardiographic pattern of Early Repolarization (ER) has been known for decades and was generally considered a benign normal variant of the surface ECG. ER is characterized by a slurring or notching elevation at the QRS-ST junction, producing a positive hump, called the J wave. However, recently evidence of the potentially hazardous nature of ER has emerged, when ER was associated with an increased risk for idiopathic ventricular fibrillation and death from cardiac causes. The pathophysiological mechanisms underlying ER are unclear. To investigate a potential genetic tendency, we determined the heritability of ER in families representative of the normal population.
Methods: 520 Caucasian nuclear families (2,037 subjects) were recruited from the general population through general practices in Leicestershire (UK) as part of Genetic Regulation of Arterial Pressure of Humans in the Community (GRAPHIC) study. Each subject was phenotyped for a wide range of cardiovascular risk factors including 12-lead ECG. The ECGs were independently read by two blinded, experienced cardiologists. ER was defined as J-point elevation of ≥0.1 mV in at least two adjacent inferior (II, III, aVF) or anterolateral (I, aVL, V4-6) leads. A total of 1,890 individuals (955 men) with complete phenotypic information were included in the analysis. Heritability estimates were computed using variance components analysis implemented in SOLAR and adjusted for age, age and gender.
Results: ER was present in n=145 individuals (7.7%), with higher prevalence in men (n=110, 11.5% of men) as compared to women (n=35, 3.7%; chi p=2.2*10−10). Heritability for the presence of ER was h=0.49 (SE 0.14; p=0.0002). Individuals with at least one affected parent had a 2.6-fold increased risk for ER (adjusted OR, 95% CI 1.45 - 4.62; p=0.001).
Conclusion: ER has a high and significant heritability. Further analyses are now warranted to identify potential target genes that affect ER and to elucidate the pathophysiology of ER.
- © 2010 by American Heart Association, Inc.