EPIDEMIOLOGY

Persistent ischaemic 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 Ström Möller¹, Björn Zethelius², Johan Sundström³, Lars Lind^3,4

¹ AstraZeneca R&D Södertälje, Södertälje, Sweden
² Departments of Public Health and Caring Sciences, Uppsala University, Uppsala Science Park, Uppsala, Sweden
³ Department of Medical Sciences, Uppsala University Hospital, Uppsala, Sweden
⁴ AstraZeneca R&D, Mölndal, Sweden

Correspondence to:
Dr C S Möller
Department of Public Health and Caring Sciences/Geriatrics, Uppsala Science Park, 75185 Uppsala, Sweden; Christina.Strom_moller{at}pubcare.uu.se

Objective: To determine the effect of new, persistent or reverted ischaemic ECG abnormalities at ages 50 and 70 years on the risk of subsequent cardiovascular disease.

Design, setting and participants: A prospective community-based observational cohort of 50-year-old men in Sweden, followed for 32 years. 2322 men of age 50 years participated in 1970–3, and 1221 subjects were re-examined at the age of 70 years.

Main outcome measures: Myocardial infarction (MI), cardiovascular mortality and overall mortality.

Results: At 50 years of age, after adjusting for established conventional risk factors, T wave abnormalities, ST segment depression, major Q/QS pattern and ECG-left ventricular hypertrophy were all found to be independent risk factors for the main outcome measures during the 32 years of follow-up. When ECG variables were re-measured at 70 years of age, they were still found to be independent risk factors for the mortality outcomes, but lost in significance for prediction of MI. Regarding mortality, it was twice as dangerous to have persistent T wave abnormalities (HR 4.63; 95% CI 2.18 to 9.83) or ST segment depression (HR 5.66; 95% CI 1.77 to 18.1), as with new T wave abnormalities (HR 2.20; 95% CI 1.48 to 3.29) or ST segment depression (HR 2.55; 95% CI 1.74 to 3.75), developing between ages 50 and 70 years. The addition of "ECG indicating ischaemia" 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 a risk for future mortality compared with new or reverted abnormalities.

Abbreviations: CVD, cardiovascular disease; LBBB, left bundle branch block; LVH, left ventricular hypertrophy; MC, Minnesota Code; MI, myocardial infarction; ROC, receiver-operating characteristics

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