July 27, 2010Open Access

Association of Early Repolarization Pattern on ECG with Risk of Cardiac and All-Cause Mortality: A Population-Based Prospective Cohort Study (MONICA/KORA)

Q: What is the clinical evidence from this study?

Study design: Cohort. Population: Early repolarization pattern (ERP) (n=6213). Intervention: Early repolarization pattern (ERP) on ECG vs. Absence of ERP. Primary outcome: Cardiac mortality (in individuals aged 35-54 years) (HR 1.96, 95% CI 1.05-3.68, p=0.035).

Key Result

Early repolarization pattern on ECG was associated with an increased risk of cardiac mortality (HR 1.96) in individuals aged 35 to 54 years.

Study Design

Type

Cohort (n=6,213)

Multicenter

PICO

Population

Early repolarization pattern (ERP) (n=6,213)

Intervention / Comparator

Early repolarization pattern (ERP) on ECG vs Absence of ERP

Primary Outcome

Cardiac mortality (in individuals aged 35-54 years) — HR 1.96 (1.05-3.68), p=0.035

Main Result

Effect estimate: HR 1.96 (95% CI 1.05-3.68)

p-value: p=0.035

Limitations

Ascertainment of death by death certificates only, which may bias towards common causes of death
Strictly epidemiologic nature of the investigation cannot clarify pathophysiologic and pathogenetic circumstances
Cannot comment on the influence of ERP outside the age range of 35-74 years
Repetitive recordings of ECGs in the same individuals were not available to determine if ERP is a permanent or transient pattern

Abstract

BACKGROUND: Early repolarization pattern (ERP) on electrocardiogram was associated with idiopathic ventricular fibrillation and sudden cardiac arrest in a case-control study and with cardiovascular mortality in a Finnish community-based sample. We sought to determine ERP prevalence and its association with cardiac and all-cause mortality in a large, prospective, population-based case-cohort study (Monitoring of Cardiovascular Diseases and Conditions MONICA/KORA Cooperative Health Research in the Region of Augsburg) comprised of individuals of Central-European descent. METHODS AND FINDINGS: Electrocardiograms of 1,945 participants aged 35-74 y, representing a source population of 6,213 individuals, were analyzed applying a case-cohort design. Mean follow-up was 18.9 y. Cause of death was ascertained by the 9th revision of the International Classification of Disease (ICD-9) codes as documented in death certificates. ERP-attributable effects on mortality were determined by a weighted Cox proportional hazard model adjusted for covariables. Prevalence of ERP was 13.1% in our study. ERP was associated with cardiac and all-cause mortality, most pronounced in those of younger age and male sex; a clear ERP-age interaction was detected (p = 0.005). Age-stratified analyses showed hazard ratios (HRs) for cardiac mortality of 1.96 (95% confidence interval CI 1.05-3.68, p = 0.035) for both sexes and 2.65 (95% CI 1.21-5.83, p = 0.015) for men between 35-54 y. An inferior localization of ERP further increased ERP-attributable cardiac mortality to HRs of 3.15 (95% CI 1.58-6.28, p = 0.001) for both sexes and to 4.27 (95% CI 1.90-9.61, p<0.001) for men between 35-54 y. HRs for all-cause mortality were weaker but reached significance. CONCLUSIONS: We found a high prevalence of ERP in our population-based cohort of middle-aged individuals. ERP was associated with about a 2- to 4-fold increased risk of cardiac mortality in individuals between 35 and 54 y. An inferior localization of ERP was associated with a particularly increased risk. Please see later in the article for the Editors' Summary.

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