Key result
Advancing age and body mass index independently predicted an increase in heart-rate corrected QT interval (P<0.01 and P=0.04, respectively), whereas age did not predict QT dispersion.
Why the study?
Does age affect QT interval and QT dispersion in healthy subjects?
Observational (n=191)
No
Does age affect QT interval and QT dispersion in healthy subjects?
p-value: p=<0.01
Age and body mass index independently predict QT interval prolongation in healthy subjects, whereas age does not predict QT dispersion.
May support age- and BMI-adjusted QTc norms in healthy adults; leaves open effects on dispersion and arrhythmic risk.
OBJECTIVE: although the isolated effects of age on QT interval and QT dispersion (QTd) have been previously investigated, no data are available on the simultaneous effects of age and other physiological or lifestyle factors on QT interval and QTd in healthy subjects. We studied the effects of age, gender, body mass index, smoking status, and blood pressure on these electrocardiographic parameters. DESIGN: observational study. SETTING: academic medical centre. PARTICIPANTS AND MEASUREMENTS: age, gender, body mass index, smoking status, and blood pressure were obtained from 191 consecutive healthy subjects (101 males and 90 females, age range 19-89 years). The subjects were divided into three groups according to their age: <30 (n=56), 30-65 (n=49), and >65 years (n=86). RESULTS: heart-rate corrected QT interval (QTc, Bazett's formula) progressively increased with advancing age (389+/-3 vs. 411+/-4 vs. 418+/-3 ms, means+/-SEM; P<0.01). By contrast, no differences in QTd were observed across the three groups (36+/-2 vs. 35+/-3 vs. 40+/-2 ms, P=NS). A multivariate regression analysis showed that age (P<0.01) and body mass index (P=0.04) independently predicted QT interval while gender was a weak (P=0.09) predictor of QTd. CONCLUSIONS: after adjusting for gender, smoking status, and blood pressure, age and body mass index independently predicted QT interval in healthy subjects. By contrast, age is not a predictor of QTd. The increase of QT interval associated with ageing and body mass index might be secondary to cardiac hypertrophy and myocardial action potential prolongation.
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Arduino A. Mangoni (2003) conducted an observational in Healthy subjects (n=191). Advancing age vs. Younger age was evaluated on Heart-rate corrected QT interval (QTc) and QT dispersion (QTd) (p=<0.01). Advancing age and body mass index independently predicted an increase in heart-rate corrected QT interval (P<0.01 and P=0.04, respectively), whereas age did not predict QT dispersion.
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