August 1, 1994Circulation273 citationsOpen Access
Association between QT interval and coronary heart disease in middle-aged and elderly men. The Zutphen Study.
Key Result
Men with a prolonged heart-rate-adjusted QT interval (≥420 ms1/2) had a significantly higher risk of coronary heart disease mortality compared to those with a short QTc (<385 ms1/2), with a rate ratio of 4.3 in middle-aged men.
Study Design
Type
Cohort (n=1,588)
Multicenter
No
Structured PICO
Does prolonged QTc predict myocardial infarction and coronary heart disease death in middle-aged and elderly men?
P
Population
1,588 middle-aged and elderly men from the general population of Zutphen, free of prior myocardial infarction, followed for up to 25 years to assess cardiovascular outcomes.
E
Exposure
Prolonged QTc (≥420 ms1/2)
C
Comparator
QTc less than 385 ms1/2
O
Outcome
Myocardial infarction and coronary heart disease deathhard clinical
Prolonged QTc within the normal range is an independent predictor of myocardial infarction and coronary heart disease death in middle-aged and elderly men, suggesting its utility in risk stratification.
Main Result
Relative Risk: 4.3 (95% CI 1.3–13.8)
Absolute Event Rate: 21.9% vs 11.1%
Limitations
- Measurement of QT interval by a single observer
- QT interval not measured in all available leads
- Ascertainment of sudden death prone to misclassification
- Lack of information on drug use before 1985
- Potential confounding by subclinical heart disease
Abstract
BACKGROUND: Heart-rate-adjusted QT-interval (QTc) is prognostic of sudden death in myocardial infarction patients. So far, population studies have yielded conflicting results on the predictive value of QTc for coronary heart disease morbidity and mortality. Therefore, we investigated this in a longitudinal study of middle-aged and elderly men. METHODS AND RESULTS: From 1960 to 1985, 877 middle-aged men were followed and repeatedly examined in the Zutphen Study. In 1985 the remaining cohort was extended to 835 elderly men from the same birth cohort and followed until 1990. Men with prolonged QTc (420 ms1/2 or more) had a higher risk of myocardial infarction and coronary heart disease death relative to men with QTc less than 385 ms1/2. Age-adjusted coronary heart disease mortality rate ratios were 4.3 (95% confidence interval, 1.3 to 13.8) in middle-aged men and 3.3 (95% confidence interval, 1.0 to 11.6) in elderly men. These associations could not be attributed to prevalent heart disease and were independent of other cardiovascular risk factors. CONCLUSIONS: These results indicate that within the normal range of QTc in the general population, men with long QTc are at higher risk for coronary heart disease. Because QTc is easily determined, it may provide a valuable contribution to risk stratification.