Attention deficit/hyperactivity disorder (ADHD) is associated with complex neurocardiac integrity. We aimed to study heart rate time asymmetry as a nonlinear qualitative feature of heart rate variability indicating complexity of cardiac autonomic control at rest and in response to physiological stress (orthostasis) in children suffering from ADHD. Twenty boys with ADHD and 20 healthy age-matched boys at the age of 8 to 12 years were examined. The continuous ECG was recorded in a supine position and during postural change from lying to standing (orthostasis). Time irreversibility indices - Porta’s (P%), Guzik’s (G%) and Ehlers’ (E) - were evaluated. Our analysis showed significantly reduced heart rate asymmetry indices at rest (P%: 49.8 % vs. 52.2 %; G%: 50.2 % vs. 53.2 %; p<0.02), and in response to orthostatic load (P%: 52.4 % vs. 54.5 %, G%: 52.3 % vs. 54.5 %; p<0.05) associated with tachycardia in ADHD children compared to controls. Concluding, our study firstly revealed the altered heart rate asymmetry pattern in children suffering from ADHD at rest as well as in response to posture change from lying to standing (orthostasis). These findings might reflect an abnormal complex cardiac regulatory system as a potential mechanism leading to later cardiac adverse outcomes in ADHD., I. Tonhajzerová, I. Ondrejka, I. Farský, Z. Višňovcová, M. Mešťaník, M. Javorka, A. Jurko Jr., A. Čalkovská., and Obsahuje bibliografii
The altered regulation of autonomic response to mental stress can result in increased cardiovascular risk. The laboratory tests used to simulate the autonomic responses to real-life stressors do not necessarily induce generalized sympathetic activation; therefore, the assessment of regulatory outputs to different effector organs could be important. We aimed to study the cardiovascular sympathetic arousal in response to different mental stressors (Stroop test, mental arithmetic test) in 20 healthy students. The conceivable sympathetic vascular index - spectral power of low frequency band of systolic arterial pressure variability (LF-SAP) and novel potential cardiosympathetic index - symbolic dynamics heart rate variability index 0V% were evaluated. The heart and vessels responded differently to mental stress - while Stroop test induced increase of both 0V% and LF-SAP indices suggesting complex sympathetic arousal, mental arithmetic test evoked only 0V% increase compared to baseline (p<0.01, p<0.001, p<0.01, respectively). Significantly greater reactivity of LF-SAP, 0V%, heart rate (HR) and mean arterial pressure (MAP) were found in response to Stroop test compared to mental arithmetic test potentially indicating the effect of different central processing (0V%, LF-SAP: p<0.001; HR, MAP: p<0.01). The different effectors’ sympathetic responses to cognitive stressors could provide novel important information regarding potential pathomechanisms of stress-related diseases., M. Mestanik, A. Mestanikova, Z. Visnovcova, A. Calkovska, I. Tonhajzerova., and Obsahuje bibliografii
The aim of the study was to evaluate short-term heart rate variability (HRV) as an index of cardiac autonomic control in rats with lipopolysaccharide (LPS)-induced endotoxemia. Animals were injected intraperitoneally with LPS (100 μg/kg b.w.) and control group with an equivalent volume of saline. ECG recordings were done before (base) and 60, 120, 180, 240 and 300 min after LPS or saline administration. HRV magnitude was quantified by time and frequency-domain analysis (mean RR interval, SDRR, RMSSD, spectral powers in low (LF) and high frequency (HF) bands. Heart tissue homogenates and plasma were analyzed to determine interleukin 6 (IL-6), tumor necrosis factor alpha (TNF-α) and oxidative stress level (TBARS). Administration of lipopolysaccharide was followed by continuous rise in colonic body temperature compared to saline-treated controls. Endotoxemia in rats was accompanied by significant decrease in HRV spectral activity in high-frequency range at maximal body temperature (logHFpower: 1.2±0.5 vs. 1.9± 0.6 ms2, P<0.01). Increased IL-6 was found in heart tissue homogenates of LPS rats (8.0±0.6 vs. 26.4±4.8 pg/ml, (P<0.05). In conclusions, reduced HRV in HF band may indicate a decreased parasympathetic activity in LPS-induced endotoxemia as basic characteristics of altered cardiac control during response to endotoxemia., I. Zila, D. Mokra, J. Kopincova, M. Kolomaznik, M. Javorka, A. Calkovska., and Obsahuje bibliografii