EARLY REPOLARIZATION INHERITANCE PATTERN IN CARDIAC ARREST SURVIVORS WITH PRESERVED EJECTION FRACTION REGISTRY (CASPER)

Abstract

Early repolarization (ER) has been historically considered to be benign, but more recently shown to be associated with increased risk of sudden death. Our objective was to determine the frequency and inheritance pattern of ER among patients with unexplained cardiac arrest and their first degree relatives. The unexplained cardiac arrest probands and their first degree relatives in the Cardiac Arrest Survivors with Preserved Ejection Fraction Registry (CASPER) were included in the ECG analysis. ER was defined as J-point elevation ≥ 0.1 mV above the isoelectric line in ≥ 2 contiguous inferior (II, III, avF) or lateral leads (I, avL, V4-V6), excluding V1-V3. The ER pattern was further characterized by its appearance (notch vs. slur) and the associated ST segment (horizontal/descending vs. ascending/up sloping). One hundred and seventy-eight subjects from 12 Canadian sites were studied (age 49 ±17 years, 88 males). A total of 560 ECGs were analyzed (3 ± 2 ECGs/subject). Overall, ER was observed in 42 of 178 subjects (24%). ER was localized in the inferior leads in 12, lateral in 15 and inferolateral in 15. Horizontal/descending ST segment was seen in 35 and ascending/up sloping in 7. The notch pattern was seen in 19, slurring in 16 and both in 7. The maximum J point elevation was 1.4 ± 0.6 mm. There was a higher proportion of ER in probands than first-degree relatives (34/104, 33% vs. 8/74, 11%, p=0.0007). There was a trend towards more ER in males than females (28% vs. 19%, p = 0.13). Among the 104 probands, 44 had at least one first degree relatives enrolled; ER was seen in 16/44 (36%). There is a trend towards more ER in the first degree relatives whose probands were ER positive compared to those whose probands were ER negative (16% vs. 8%, p=0.30). ER was more commonly observed in unexplained cardiac arrest probands compared to the first-degree relatives. There was a trend towards more ER in the first degree relatives whose probands were ER positive.