Background: Previous studies have shown that ST depressions > or =1.0 mm during or post-exercise increase long-term risk of dying from coronary heart disease (CHD), the need for coronary artery bypass grafting (CABG) or the development of acute myocardial infarction (AMI) in healthy men. In the present prospective cohort study we investigate whether less marked ST depressions may influence CHD mortality, incidence of AMI, the need for a CABG or having a non-fatal stroke.
Methods: During 1972-75, 2014 men aged 40-59 years, free from somatic diseases and not using any drugs, underwent an examination programme including case history, clinical examination, various blood tests and a symptom-limited exercise ECG-test. ECG was registered during exercise and at 30 s, 1, 2, 3 and 5 min post-exercise. The possible prognostic impact of ST-changes of 0.50-0.99 mm and > or =1.00 mm compared with normal ST-segments were studied separately and combined. Horizontal, down-sloping and slowly up-sloping ST-segment patterns were combined.
Results: After adjustment for age, smoking, blood pressure, cholesterol, maximal heart rate, left ventricular hypertrophy and physical fitness ST depressions > or =0.50 mm--during and/or post-exercise--were associated with a 1.47-fold [95% confidence interval (CI) 1.10-1.95], and 1.54-fold (95% CI of 1.17-2.04) increased 26 years risk of CHD-mortality, respectively. The same ST-changes also increased 22 years risk of developing non-fatal AMI or needing CABG but not developing non-fatal stroke.
Conclusions: Even an ST depression > or =0.50 mm during and/or after exercise increases the long-term risk of CHD-death, developing an AMI or needing CABG. No association was found between ST-changes and incidence of non-fatal strokes.