Cardiac Autonomic Nervous System (cardiac + autonomic_nervous_system)

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Medical Sciences100%

Selected Abstracts

Effect of intensive training on heart rate variability in prepubertal swimmers

EUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 10 2005
A. Vinet
Abstract Background, In children, there is very limited evidence focusing on the beneficial effect of exercise training on heart rate variability (HRV) during childhood. Despite the fact that more and more children are engaged in intensive training programs, the question arises if such intensive training involves deleterious effects on the cardiac autonomic nervous system during childhood. Thus the aim of the present study was to compare HRV parameters in highly trained swimmer boys and untrained counterparts. Methods, Twenty prepubertal boys, aged 11,12 years old, took part in the study. The children were divided into 11 highly trained prepubertal swimmers (training sessions of 8,10 h weekly for at least 4 years) and 9 age-matched active boys. HRV analysis was performed on diurnal recordings in the frequency (short-term recordings 6 min the most ,vagal') and time (long-term recordings 4 h centred on the 6 min most ,vagal') domains. Results, No significant differences were obtained between groups for all frequency variables whatever the mode of expression (absolute in ms2, relative in Ln or %). All time-domain components were not significantly different in swimmers and untrained boys. Conclusions, The results of the present study demonstrate that participating intensively in swimming training does not induce in children changes in HRV indices. Neither time nor domain HRV variables were significantly different between untrained and highly trained prepubertal boys. Thus, intensive training in healthy children does not involve deleterious effects on HRV. [source]

Effects of glucose ingestion on cardiac autonomic nervous system in healthy centenarians: differences with aged subjects

EUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 4 2000
Paolisso
Background Spectral analysis of heart rate variability (HRV) investigates the cardiac autonomic nervous system (ANS) activity. In particular, low frequency/high frequency (LF/HF) is considered an index of cardiac sympatho-vagal balance and is stimulated by glucose ingestion in healthy subjects. No studies have evaluated the effect of glucose ingestion on cardiac ANS in centenarians. Materials and methods In 30 healthy centenarians (HC) and 25 aged subjects (AS) power spectral analysis of HRV was investigated during an oral glucose ingestion. Results Glucose ingestion rose LF/HF ratio in both groups studied. Such stimulatory effects were restrained to the first 60 min of the study. Independent of age, gender, body mass index (BMI) and fasting plasma norepinephrine and FT3 concentrations, HC had basal total power (1318 ± 546 vs. 1918 ± 818 msec2, P < 0.01), lower low frequency (LF) (33 ± 21 vs. 50 ± 11 n.u. , P < 0.03), and higher high frequency (HF) (74 ± 18 vs. 43 ± 15 n.u., P < 0.05) than AS. Consequently, LF/HF ratio (0.43 ± 0.07 vs. 0.91 ± 0.05, P < 0.02) was also lower in HC than in AS. In AS, but not in HC, the baseline LF/HF ratio correlated significantly with BMI (r = 0.48, P < 0.01), waist-hip-ratio (WHR) (r = 0.45, P < 0.02), fasting plasma insulin (r = 0.49, P < 0.01) and norepinephrine (r = 0.57, P < 0.02) concentration. Glucose ingestion was associated with a significant rise in LF/HF ratio in both groups studied but per cent changes in glucose mediated stimulation of LF/HF was lower in HC than in AS. In a control study, water administration did not affect power spectral parameters of HRV. Conclusion Our study demonstrates that basal- and glucose-stimulated LF/HF, an indirect index of cardiac sympatho-vagal balance, are lower in HC than in AS. [source]

Natriuretic peptides in relation to the cardiac innervation and conduction system

MICROSCOPY RESEARCH AND TECHNIQUE, Issue 5 2002
Magnus HanssonArticle first published online: 10 SEP 200
Abstract During the past two decades, the heart has been known to undergo endocrine action, harbouring peptides with hormonal activities. These, termed "atrial natriuretic peptide (ANP)," "brain natriuretic peptide (BNP)," and "C-type natriuretic peptide (CNP)," are polypeptides mainly produced in the cardiac myocardium, where they are released into the circulation, producing profound hypotensive effects due to their diuretic, natriuretic, and vascular dilatory properties. It is, furthermore, well established that cardiac disorders such as congestive heart failure and different forms of cardiomyopathy are combined with increased expression of ANP and BNP, leading to elevated levels of these peptides in the plasma. Besides the occurrence of natriuretic peptides (NPs) in the ordinary myocardium, the presence of ANP in the cardiac conduction system has been described. There is also evidence of ANP gene expression in nervous tissue such as the nodose ganglion and the superior cervical ganglion of the rat, ganglia known to be involved in the neuronal regulation of the heart. Furthermore, in the mammalian heart, ANP appears to affect the cardiac autonomic nervous system by sympathoinhibitory and vagoexcitatory actions. This article provides an overview of the relationship between the cardiac conduction system, the cardiac innervation and NPs in the mammalian heart and provides data for the concept that ANP is also involved in neuronal cardiac regulation. Microsc. Res. Tech. 58:378,386, 2002. © 2002 Wiley-Liss, Inc. [source]