Sympathovagal balance, nighttime blood pressure, and QT intervals in normotensive obese women.
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.


METHODS
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).


CONCLUSIONS
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.
Esposito
Katherine
K
Department of Geriatrics and Metabolic Diseases, Cardiovascular Research Center, Second University of Naples, Naples, Italy. katherine.esposito@unina2.it
Marfella
Raffaele
R
Gualdiero
Pasquale
P
Carusone
Caterina
C
Pontillo
Alessandro
A
Giugliano
Giovanni
G
Nicoletti
Gianfranco
G
Giugliano
Dario
D
D000328:Adult; D001341:Autonomic Nervous System / Q000503:physiopathology; D001786:Blood Glucose / Q000378:metabolism; D001794:Blood Pressure / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology; D015716:Electrocardiography, Ambulatory; D005260:Female; D005947:Glucose / Q000378:metabolism; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D007328:Insulin / Q000378:metabolism; D009765:Obesity / Q000503:physiopathology*; D015431:Weight Loss / Q000502:physiology
D001786:Blood Glucose; D007328:Insulin; D005947:Glucose