Persistent Ischemic ECG Abnormalities on Repeated ECG Examination Have Important Prognostic Value for Cardiovascular Disease Beyond Established Risk Factors: A population-based study in middle-aged men with up to 32 years of follow-up

Christina Strom Moller ^1*, Bjorn Zethelius ¹, Johan Sundstrom ² and Lars Lind ²

¹ Departments of Public Health and Caring Sciences, Section of Geriatrics, Uppsala, Sweden
² Department of Medical Sciences, Uppsala University, Sweden

^* To whom correspondence should be addressed. E-mail: christina.strom_moller{at}pubcare.uu.se.

Accepted 16 January 2007

Abstract

Objective To determine how new, persistent, or reverted ischemic ECG abnormalities at ages 50 and 70 affect the risk of subsequent cardiovascular disease.

Design, Setting, and Participants Prospective community-based observational cohort of 50-year-old men in Sweden, followed for 32 years. 2322 men participated at age 50 in 1970-1973, and 1221 subjects were re-examined at age 70.

Main outcome measures Myocardial infarction, cardiovascular mortality, and overall mortality.

Results At age 50, after adjusting for established conventional risk factors, T wave abnormalities, ST segment depression, major Q/QS pattern, and ECG-LVH were all independent risk factors for the main outcome measures during 32 years of follow-up. When ECG variables were re-measured at age 70, they were still independent risk factors for the mortality outcomes, but lost in significance for prediction of myocardial infarction. Regarding mortality, it was twice as dangerous to have persistent T wave abnormalities (HR, 4.63; 95% CI, 2.18-9.83) or ST segment depression (HR, 5.66; 95% CI; 1.77-18.1), compared to new T wave abnormalities (HR, 2.20; 95% CI, 1.48-3.29) or ST segment depression (HR, 2.55; 95% CI, 1.74-3.75), developing between ages 50 and 70. The addition of "ECG indicating ischemia" significantly increased the predictive power of the Framingham score (p<0.001).

Conclusions It is worthwhile to obtain serial ECGs for proper risk assessment, since persistent ST-T abnormalities carried twice as high risk for future mortality, compared to new or reverted abnormalities.

Keywords: cardiovascular mortality, electrocardiogram, myocardial infarction, population studies, risk factors

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