Open AccessSympathovagal Balance, Nighttime Blood Pressure, and QT Intervals in Normotensive Obese Women
Author(s) -
Esposito Katherine,
Marfella Raffaele,
Gualdiero Pasquale,
Carusone Caterina,
Pontillo Alessandro,
Giugliano Giovanni,
Nicoletti Gianfranco,
Giugliano Dario
Publication year - 2003
Publication title -
obesity research
Language(s) - English
Resource type - Journals
eISSN - 1550-8528
pISSN - 1071-7323
DOI - 10.1038/oby.2003.93
Subject(s) - qt interval , medicine , blood pressure , endocrinology , cardiology , heart rate variability , diastole , heart rate , balance (ability) , physical therapy
Objective : We describe associations among the heart‐rate‐corrected QT (QTc) interval, QTc dispersion (QTc‐d), circadian BP variation, and autonomic function in obese normotensive women and the effect of sustained weight loss. Research Methods and Procedures : In 71 obese (BMI = 37.14 ± 2.6 kg/m 2 ) women, 25 to 44 years of age, circadian BP variations (24‐hour ambulatory BP monitoring), autonomic function (power spectral analysis of RR interval oscillations), and cardiac repolarization times (QTc‐d and QTc interval) were recorded at baseline and after 1 year of a multidisciplinary program of weight reduction. Results : Compared with nonobese age‐matched women ( n = 28, BMI = 23 ± 2.0 kg/m 2 ), obese women had higher values of QTc‐d ( p < 0.05) and QTc ( p < 0.05), an altered sympathovagal balance (ratio of low‐frequency/high‐frequency power, p < 0.01), and a blunted nocturnal drop in BP ( p < 0.01). In obese women, QTc‐d and the QTc interval correlated with diastolic nighttime BP ( p < 0.01) and sympathovagal balance ( p < 0.01). Waist‐to‐hip ratio, free fatty acids, and plasma insulin levels correlated with QT intervals and reduced nocturnal drops in both systolic and diastolic BP and sympathovagal balance ( p < 0.01). After 1 year, obese women lost at least 10% of their original weight, which was associated with decrements of QTc‐d ( p < 0.02), the QTc interval ( p < 0.05), nighttime BP ( p < 0.01), and sympathovagal balance ( p < 0.02). Discussion : Sustained weight loss is a safe method to ameliorate diastolic nighttime BP drop and sympathetic overactivity, which may reduce the cardiovascular risk in obese women.