Normalization of Maximal Cardiovascular Variables for Body Size in Premenarcheal Girls

Rowland, Thomas W.; Goff, Donna A.; Martel, Leslie; Ferrone, Lisa; Kline, G.

doi:10.1007/s002460010102

Cited by 14 publications

(14 citation statements)

References 7 publications

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“…53 In premenarchal girls, allometric scaling of V O 2 max eliminated the effects of body size, whereas ratiometric scaling methods did not. 54 Similarly, in athletes, the associations between body size and allometrically scaled V O 2 max were minimal in cross-sectional 49 and longitudinal 50,51 studies, whereas significant correlations between body size and unscaled V O 2 max were observed.…”

Section: Evidence For Allometric Scaling Of Cardiovascular Functionmentioning

confidence: 95%

Does Size Matter?

et al. 2008

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Abstract-Extensive evidence is available that cardiovascular structure and function, along with other biological properties that span the range of organism size and speciation, scale with body size. Although appreciation of such factors is commonplace in pediatrics, cardiovascular measurements in the adult population, with similarly wide variation in body size, are rarely corrected for body size. The patient is a very tall 23-yearold competitive rower with a height of 203 cm and weight of 100 kg referred to the clinic for preparticipation athletic screening. He has never experienced syncope, palpitations, or chest pain during exertion and has no significant past medical history, but he occasionally feels "light-headed" at the end of an exhaustive competitive workout. He has no family history of sudden cardiac death or of premature cardiovascular disease. He is actively training 5 to 6 hours per day, 6 days per week in preparation for the upcoming Olympic Games. The examination is remarkable only for a soft systolic ejection murmur, cardiomegaly, and a third heart sound. An ECG is ordered, which is remarkable for sinus bradycardia, a 15-mV R wave in lead aVL, and R-wave voltage in lead V 5 plus S-wave voltage in lead V 1 totaling 46 mV. On a follow-up echocardiogram, septal and posterior wall thicknesses of 14.5 mm are observed with a left ventricular (LV) internal dimension in diastole of 53 mm. No significant obstructive LV outflow pattern is present, and wall thickness appears symmetrical. On the basis of current echocardiographic criteria, this patient is in the "gray zone" between physiological and pathological hypertrophy. His nonspecific symptoms and lack of other contributing history add to the ambiguity in diagnosis. Clinical Vignette No. 2:The patient is a 66-year-old woman who has a height of 155 cm and a body mass of 49 kg.She has a history of hyperlipidemia and abdominal aortic aneurysm. She comes to the clinic for her yearly ultrasound follow-up, which shows a maximum aneurysm diameter of 50 mm. She is in a "gray zone" in which neither surgical correction nor watchful waiting is definitively indicated.Considerable evidence is available that biological processes from metabolic enzyme activity 1 to plant and animal metabolic rates 2-4 to cancer metastasis 5 scale with body size over the entire range of organism size and speciation. Cardiovascular structural and functional variables also scale with body size. Compare, for instance, the blue whale, which has a heart mass of 600 kg and a resting heart rate of 6 bpm, with the smallest mammal, the shrew, which has a heart mass of 12 mg and a resting heart rate of up to 1200 bpm. 6 Despite the clear relationship between body size and cardiovascular dimensions and functional parameters, the practice of scaling cardiovascular measurements is poorly applied in adult clinical cardiology. This contrasts with pediatric medicine, in which measurements are universally indexed to body size. The intuitive idea that body growth implies a greater need for scaling in pe...

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Section: Evidence For Allometric Scaling Of Cardiovascular Functionmentioning

confidence: 95%

Does Size Matter?

et al. 2008

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“…Also, alometric scaling of VO 2max to account for size differences is an important issue. Strong cases have been made for scaling VO 2max , stroke volume, cardiac output and other size-related physiological variables relative to body surface area in children 37,38 .…”

Section: Physical Activity Aerobic Fitness and Blood Lipid Profilementioning

confidence: 99%

Adiposity, Physical Activity and Blood Lipid Profile in 13-year-old Adolescents

Ostojić

Stojanović²,

Stojanovic³

et al. 2010

Journal of Pediatric Endocrinology and Metabolism

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The main aim of this study was to determine the extent to which physical activity and adiposity are associated with blood cholesterol levels in male adolescents. Anthropometric and physical fitness values were measured in all children. Body mass index (BMI) and physical activity index (PAI) were used to split participants into active overweight (ACO) and non-active normal-weight (NAN) groups. The cutoffs for the ACO group were BMI ≥ 22.6 kg/m 2 and PAI ≥ 3.5, respectively, whereas the corresponding cutoffs for the NAN groups were BMI < 20.0 kg/m 2 and PAI < 2. A total of 65 children (29 in ACO group, 36 in NAN group) were selected according to above criteria. ACO group showed significantly higher BMI and body fat as compared to their NAN counterparts (p < 0.05). Adolescents from ACO group attained superior score for PAI and aerobic fitness (p < 0.05). Most blood lipid variables were significantly lower in ACO group as compared to NAN (p < 0.05) while HDL-cholesterol was higher in ACO group (p < 0.05). There was significant positive correlation between HDLcholesterol and PAI in ACO group (r = 0,38; p < 0.05). Physical activity index explained the majority of variance in HDL-cholesterol for ACO group (β = 0,513; p < 0.05). It seems that physical activity in adolescents is more important factor in balancing blood lipid status than adiposity per se, particularly for HDL-cholesterol.

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“…Supporting evidence for the vasodilatory effects of nitrite can be derived by examining the components of CI in the log scale ( Fig. 2) (68). In this format, the individual contributions of each component of CI are additive (normal scale: CI ϭ SVI ϫ HR, log scale: log CI ϭ log SVI ϩ log HR, where SVI is the stroke volume index).…”

Section: Physiological Effects Of Intravenous Sodium Nitritementioning

confidence: 99%

“…Effects of nitrite on the components of the CI in nonhemolyzing animals. The CI (A) and its components (B) were transformed into the log scale to demonstrate the individual contribution of heart rate (HR) and stroke volume index (SVI) to CI in an additive fashion (normal scale: CI ϭ SVI ϫ HR, log scale: log CI ϭ log SVI ϩ log HR) (68). In animals receiving D5W and nitrite, the nitrite-induced increase in the CI is mediated predominantly through an increase in SVI and to a lesser extent by a chronotropic effect.…”

Section: Nitrite Levels and Hb Species Formed During Intravascular Hementioning

confidence: 99%

Nitrite reductase activity of hemoglobin as a systemic nitric oxide generator mechanism to detoxify plasma hemoglobin produced during hemolysis

Minneci

Deans²,

Shiva³

et al. 2008

American Journal of Physiology-Heart and Circulatory Physiology

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Hemoglobin (Hb) potently inactivates the nitric oxide (NO) radical via a dioxygenation reaction forming nitrate (NO(3)(-)). This inactivation produces endothelial dysfunction during hemolytic conditions and may contribute to the vascular complications of Hb-based blood substitutes. Hb also functions as a nitrite (NO(2)(-)) reductase, converting nitrite into NO as it deoxygenates. We hypothesized that during intravascular hemolysis, nitrite infusions would limit the vasoconstrictive properties of plasma Hb. In a canine model of low- and high-intensity hypotonic intravascular hemolysis, we characterized hemodynamic responses to nitrite infusions. Hemolysis increased systemic and pulmonary arterial pressures and systemic vascular resistance. Hemolysis also inhibited NO-dependent pulmonary and systemic vasodilation by the NO donor sodium nitroprusside. Compared with nitroprusside, nitrite demonstrated unique effects by not only inhibiting hemolysis-associated vasoconstriction but also by potentiating vasodilation at plasma Hb concentrations of <25 muM. We also observed an interaction between plasma Hb levels and nitrite to augment nitroprusside-induced vasodilation of the pulmonary and systemic circulation. This nitrite reductase activity of Hb in vivo was recapitulated in vitro using a mitochondrial NO sensor system. Nitrite infusions may promote NO generation from Hb while maintaining oxygen delivery; this effect could be harnessed to treat hemolytic conditions and to detoxify Hb-based blood substitutes.

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Normalization of Maximal Cardiovascular Variables for Body Size in Premenarcheal Girls

Cited by 14 publications

References 7 publications

Does Size Matter?

Does Size Matter?

Adiposity, Physical Activity and Blood Lipid Profile in 13-year-old Adolescents

Nitrite reductase activity of hemoglobin as a systemic nitric oxide generator mechanism to detoxify plasma hemoglobin produced during hemolysis

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