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.
Department of Geriatrics and Metabolic Diseases, Cardiovascular Research Center, Second University of Naples, Naples, Italy. katherine.esposito@unina2.it
Katherine
K
Esposito
Raffaele
R
Marfella
Pasquale
P
Gualdiero
Caterina
C
Carusone
Alessandro
A
Pontillo
Giovanni
G
Giugliano
Gianfranco
G
Nicoletti
Dario
D
Giugliano
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