57-06: Prevalence of Early Repolarization pattern in 12 lead electrocardiogram: a population based study

Abstract

Background: Early repolarization pattern (ERP) is an electrocardiogram (ECG) finding characterized by J-point elevation and QRS notching or slurring in the inferior and/or lateral leads. Its prevalence in Southern Cone of Latin America is unknown. Purpose: The main objective of the study was to determine the prevalence of ERP according to the Nomenclature suggested by Macfarlane. Methods: CESCAS I study is an observational prospective cohort study with a multistage probabilistic sample of 8000 participants aged 35-74 years from cities representing the Southern Cone of Latin America designed to estimate the prevalence and distribution of and secular trends in major cardiovascular disease events and risk factors For the present analysis we use ECGs from 1990 participants, we excluded 18 subjects for whom ECG were missing or incomplete. We also excluded 86 subjects with bundle branch block, Wolf-Parkinson-White pattern, atrial fibrillation, cardiac pacing and Brugada pattern. ERP was defined by an elevation of the J point ≥1 mm in 2 consecutive leads excluding leads V(1) through V(3). An ECG was considered ERP positive if there was J-point elevation in ≥2 leads in the inferior (II, II, aVF) or lateral (I, aVL, V4- 6) territory. Because the variation in the definition of the ERP the Macfarlane 's classification in five types were used: Types 1: notch ≥0.1 mV and elevated ST amplitude ≥0.1 mV. Types 2: notch ≥0.1 mV and elevated ST amplitude <0.1 mV. Types 3: slur ≥0.1 mV and elevated ST amplitude ST ≥0.1 mV. Types 4: slur ≥0.1 mV and elevated ST amplitude <0.1 mV. Types 5: ST elevation ≥0.1 mV without notch or slur. Two trained cardiologists from different blinded to the identity of the patients interpreted the ECGs separately and manually, and recorded the presence of an ERP. Inter-observer reliability was assessed within the observers. The disagreements were judged by the third cardiologist. Kappa test was used for inter-observer variation. Results: A total of 1886 ECGs were analysed with a male proportion of 39.8% and a mean age of 54.2 year. The prevalence of ERP was 4.77% (90/1886). The inferior location was found in 70% of cases (63/1886). The most common type was the “slurring” appearance without ST elevation (type 4) represented 68.89% of cases. Type 2 was observed in 27.78% of cases (25/1886). There was an important strength of agreement between the two initial interpreters (k= 0.89, proportion agreement 0.89). Conclusions: Consistent with published estimates ranging from 1% to 13% we found an overall prevalence of ERP of 4.77%.