Association between QT interval and coronary heart disease in middle-aged and elderly men. The Zutphen Study.
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.


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.
Dekker
J M
JM
Department of Epidemiology and Public Health, Agricultural University Wageningen, The Netherlands.
Schouten
E G
EG
Klootwijk
P
P
Pool
J
J
Kromhout
D
D
D000367:Age Factors; D000368:Aged; D015331:Cohort Studies; D003327:Coronary Disease / Q000453:epidemiology*; D016757:Death, Sudden, Cardiac / Q000453:epidemiology*; D004562:Electrocardiography; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D008133:Long QT Syndrome / Q000175:diagnosis / Q000453:epidemiology*; D008297:Male; D008875:Middle Aged; D009426:Netherlands / Q000453:epidemiology; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D011446:Prospective Studies; D012307:Risk Factors; D013997:Time Factors