Altered Cardiovascular Rhythmicity in Children Born Small for Gestational Age

Abstract

Abstract-Low birth weight is frequently associated with a disproportionately high incidence of cardiovascular disease, diabetes mellitus, and kidney disease in adulthood. Epidemiological studies have identified an inverse association between low birth weight or being small for gestational age and hypertension in adulthood. We hypothesized that children born with low birth weight might have altered circadian and ultradian cardiovascular rhythmicity independent of the prevailing blood pressure level. Twenty-four-hour ambulatory blood pressure and heart rate rhythmicity was prospectively evaluated by Fourier analysis in a cohort of healthy children born with low birth weight and compared with normative pediatric data. Seventy-five children born small for gestational age (mean age, 8.1Ϯ2.2 years) and 139 controls matched for age and sex were investigated. In addition to increased 24-hour, daytime, and especially nighttime blood pressure levels (PϽ0.05), children born small for gestational age exhibited blunted circadian (24-hour) and ultradian (12-, 8-, and 6-hour) blood pressure rhythmicity (PϽ0.05). In a multivariate analysis including children born with low birth weight and controls, being born with low birth weight independently influenced ultradian blood pressure rhythmicity, whereas in a multivariate analysis including children born with low birth weight only, circadian and ultradian rhythms were independently influenced by catch-up growth, gestational age, and blood pressure level. This study demonstrates blunted circadian and ultradian cardiovascular rhythmicity in prepubertal children born small for gestational age, independent from the presence of arterial hypertension. Circadian and ultradian rhythms may be sensitive indicators for detecting subtle early abnormalities of cardiovascular regulation. (Hypertension. 2012;60:865-870.)Key Words: small for gestational age Ⅲ low birth weight Ⅲ child Ⅲ blood pressure Ⅲ circadian and ultradian cardiovascular rhythmicity

Blood pressure (BP) assessment—from BP level to BP variability

“…Interestingly, these authors found that the changes in cardiovascular rhythmicity correlated with changes in visceral obesity, indicating that visceral fat plays an important role in the sympathetic activity of adolescents with HTN [41]. The predisposition to alterations in BP rhythmicity may even be congenital or acquired early in child's development as documented by the decreased nocturnal dipping and decreased amplitudes in children born small for gestational age and then evaluated at the age of 8 years [42]. These alterations in BP rhythmicity were observed independently from the presence of HTN.…”

Familial Aggregation and Childhood Blood Pressure

“…Low birth weight (and catch-up growth after birth) and adverse intrauterine conditions (e.g., preeclampsia) have been well-established etiologies for high BP in childhood [42–45]. Birth weight is a complex multifactorial trait itself with heritability around 20–30 % [46–49].…”

Reduced respiratory sinus arrhythmia in adults born at extremely low birth weight: Evidence of premature parasympathetic decline?

“…Because substantial development of the autonomic nervous system (ANS) occurs during the third trimester of pregnancy (Van Leeuwen, Lange et al, 1999), ANS functioning may be altered in individuals born prior to 28 weeks of gestation. Indeed, preterm birth has been linked to alterations in the development of the vasculature (Norman, 2008), ANS functioning (Yiallourou, Witcombe, et al, 2013), and cardiac rhythmicity (Wolfenstetter, Simonetti et al, 2012). Preterm birth also has been associated with higher blood pressure in adults (Bergvall, Iliadou et al, 2007; Dalziel, Parag et al, 2007) and lower heart rate variability (HRV) in children (Rakow, Katz-Salamon et al, 2013), especially if the children experienced growth-restriction in utero (Schneider, Fiedler et al, 2006).…”