Mc. De Bruyne et al., Prolonged QT interval predicts cardiac and all-cause mortality in the elderly - The Rotterdam study, EUR HEART J, 20(4), 1999, pp. 278-284
Aims To examine the association between heart-rate corrected QT prolongatio
n and cardiac and all-cause mortality in the population-based Rotterdam Stu
dy among men and women aged 55 years or older and to compare the prognostic
value of the QT interval: using different formulas to correct for heart ra
te.
Methods and Results After exclusion of participants with arrhythmias or bun
dle branch block on the EGG, the study population consisted of 2083 men and
3158 women. The QT interval was computed by the Modular ECG Analysis Syste
m (MEANS). Data were analysed using Cox' proportional hazards model. Partic
ipants In the highest quartile of the heart-rate corrected QT interval had
about a 70% age- and sex-adjusted increased risk for both all-cause mortali
ty (hazard ratio (HR) 1.8: 95%CI:1.3-2.4) and cardiac mortality (HR 1.7; 95
%CI:1.0-2.7) compared to those in the lowest quartile. In women, the increa
sed risk associated with prolonged QT for cardiac death was more pronounced
than in men. These risk estimates did not change after adjustment for pote
ntial confounders, including history of myocardial infarction, hypertension
and diabetes mellitus.
Conclusion A prolonged heart-rate corrected QT interval is an independent p
redictor for cardiac and all-cause mortality in older men and women. The ri
sk associated with prolonged QT is hardly affected by the heart-rate correc
tion formula used.