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The prognostic value of the QT interval and QT interval dispersion in all-cause and cardiac mortality and morbidity in a population of Danish citizens

H. Elming, E. Holm, L. Jun, C. Torp-Pedersen, L. Køber, M. Kircshoff, M. Malik, J. Camm
DOI: http://dx.doi.org/10.1053/euhj.1998.1094 1391-1400 First published online: 1 September 1998

Abstract

Aims.

To evaluate the prognostic value of the QT interval and QT interval dispersion in total and in cardiovascular mortality, as well as in cardiac morbidity, in a general population.

Methods and results.

The QT interval was measured in all leads from a standard 12-lead ECG in a random sample of 1658 women and 1797 men aged 30–60 years. QT interval dispersion was calculated from the maximal difference between QT intervals in any two leads. All cause mortality over 13 years, and cardiovascular mortality as well as cardiac morbidity over 11 years, were the main outcome parameters. Subjects with a prolonged QT interval (430ms or more) or prolonged QT interval dispersion (80ms or more) were at higher risk of cardiovascular death and cardiac morbidity than subjects whose QT interval was less than 360ms, or whose QT interval dispersion was less than 30ms. Cardiovascular death relative risk ratios, adjusted for age, gender, myocardial infarct, angina pectoris, diabetes mellitus, arterial hypertension, smoking habits, serum cholesterol level, and heart rate were 2·9 for the QT interval (95% confidence interval 1·1–7·8) and 4·4 for QT interval dispersion (95% confidence interval 1·0–19·1). Fatal and non-fatal cardiac morbidity relative risk ratios were similar, at 2·7 (95% confidence interval 1·4–5·5) for the QT interval and 2·2 (95% confidence interval 1·1–4·0) for QT interval dispersion.

Conclusion.

Prolongation of the QT interval and QT interval dispersion independently affected the prognosis of cardiovascular mortality and cardiac fatal and non-fatal morbidity in a general population over 11 years.

  • QT interval dispersion
  • QT interval
  • epidemiology
  • morbidity
  • mortality

Footnotes

  • f1 Correspondence:Hanne Elming, Department of Cardiology, Gentofte University Hospital, DK-2900 Hellerup, Denmark.

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