Anthropometric Determinants of Respiratory Sinus Arrhythmia in Children

Background: The study was conducted to investigate the implications of anthropometry in school-aged children on the degree of respiratory sinus arrhythmia observed in clinical settings. Methods: In a cohort study, 626 healthy children (52% male) aged 10.8 ± 0.5 years attending primary school in a single town underwent a 12-lead electrocardiogram coupled with measurements of height, weight and blood pressure. Indices of respiratory sinus arrhythmia (pvRSA, RMSSD, RMSSDc) were derived from semi-automatic measurements of RR intervals. Height, weight, BMI, blood pressure as well as waist and hip circumferences were compared between subjects with rhythmic heart rate and respiratory sinus arrhythmia, and correlations between indices of sinus arrhythmia and anthropometry were investigated. Results: Respiratory sinus arrhythmia was recognized in 43% of the participants. Subjects with sinus arrhythmia had lower heart rate (p < 0.001), weight (p = 0.009), BMI (p = 0.005) and systolic (p = 0.018) and diastolic (p = 0.004) blood pressure. There were important inverse correlations of heart rate and indices of sinus arrhythmia (r = −0.52 for pvRSA and r = −0.58 for RMSSD), but not the anthropometry. Conclusion: Lower prevalence of respiratory sinus arrhythmia among children with overweight and obesity is a result of higher resting heart rate observed in this population.

Sex and age interaction in fundamental circulatory volumetric variables at peak working capacity

Background Whether the fundamental hematological and cardiac variables determining cardiorespiratory fitness and their intrinsic relationships are modulated by major constitutional factors, such as sex and age remains unresolved. Methods Transthoracic echocardiography, central hemodynamics and pulmonary oxygen (O2) uptake were assessed in controlled conditions during submaximal and peak exercise (cycle ergometry) in 85 healthy young (20–44 year) and older (50–77) women and men matched by age-status and moderate-to-vigorous physical activity (MVPA) levels. Main outcomes such as peak left ventricular end-diastolic volume (LVEDVpeak), stroke volume (SVpeak), cardiac output (Qpeak) and O2 uptake (VO2peak), as well as blood volume (BV), BV–LVEDVpeak and LVEDVpeak–SVpeak relationships were determined with established methods. Results All individuals were non-smokers and non-obese, and MVPA levels were similar between sex and age groups (P ≥ 0.140). BV per kg of body weight did not differ between sexes (P ≥ 0.118), but was reduced with older age in men (P = 0.018). Key cardiac parameters normalized by body size (LVEDVpeak, SVpeak, Qpeak) were decreased in women compared with men irrespective of age (P ≤ 0.046). Older age per se curtailed Qpeak (P ≤ 0.022) due to lower heart rate (P < 0.001). In parallel, VO2peak was reduced with older age in both sexes (P < 0.001). The analysis of fundamental circulatory relationships revealed that older women require a higher BV for a given LVEDVpeak than older men (P = 0.024). Conclusions Sex and age interact on the crucial circulatory relationship between total circulating BV and peak cardiac filling, with older women necessitating more BV to fill the exercising heart than age- and physical activity-matched men.

AN EXPLORATORY STUDY OF PREDICTORS OF LATE ARRHYTHMIA RECURRENCES IN PATIENTS WITH PERSISTENT ATRIAL FI BRILLATION AFTER CARDIOVERSION

Introduction. The existing guidelines do not contain a clear algorithm for predicting the late recurrences of atrial fibrillation (AFib). Objectives. We have studied the predictors of late recurrence of arrhythmia in patients with persistent AFib after the restoration of sinus rhythm (SR). Research methods. A prospective single-center study included 120 hospitalized patients with persistent AFib who underwent successful cardioversion. The recurrence of AFib was assessed in the early period after cardioversion by recording 12-channel ECG, Holter ECG monitoring and event ECG monitoring. After a nine-month period follow-up visit was performed. Baseline demographic, clinical-functional features and comorbidities were compared in group with (n = 87) and without (n = 33) late recurrences of Afib. Results. There were no differences in demographic, anthropometric data and comorbidities. Patients with late recurrence of AFib had a lower heart rate (HR) after SR recovery (p <0.001). Early recurrences of AFib were found in 43 (49.4%) patients with late recurrences of arrhythmia and only in two (6.0%) without late recurrences (p <0.001). Patients with late recurrences of arrhythmia had a lower average daily HR (p <0.001), a higher number of single atrial extrasystoles (p = 0.001), atrial pairs and runs (p = 0.01) recorded by Holter ECG monitoring. Conclusions. Late recurrences of arrhythmia during the nine-month follow-up period were reported in 72.5% of patients. Groups of patients with and without late recurrence of arrhythmia had significant differences in the incidence of early recurrences, mean HR on SR, and the presence of atrial extrasystoles after rhythm recovery.

Athlete's Heart in Asian Military Males: The CHIEF Heart Study

Background: Elite athlete's heart is characterized by a greater left ventricular mass indexed by body surface area (LVMI) and diastolic function; however previous studies are mainly conducted in non-Asian athletes compared to sedentary controls.Methods: This study included 1,388 male adults, aged 18–34 years, enrolled in the same unified 6-month physical training program in Taiwan. During the midterm exams of 2020, all trainees completed a 3-km run (endurance) test, and 577 were randomly selected to attend a 2-min push-up (muscular strength) test. Elite athletes were defined as the performance of each exercise falling one standard deviation above the mean (16%). Cardiac structure and function were measured by echocardiography and compared between elite and non-elite athletes. Multiple logistic regression analysis was used to determine the independent predictors of elite athlete status at each exercise modality.Results: As compared to non-elite controls, elite endurance athletes had greater LVMI (84.4 ± 13.6 vs. 80.5 ± 12.9 g/m2, p &lt; 0.001) and lateral mitral E'/A' ratio (2.37 ± 0.73 vs. 2.22 ± 0.76, p &lt; 0.01) with lower late diastolic A' (7.77 ± 2.16 vs. 8.30 ± 3.69 cm/s, p = 0.03). Elite strength athletes had greater LVMI (81.8 ± 11.4 vs. 77.5 ± 12.1, p = 0.004) and lateral mitral E'/A' ratio (2.36 ± 0.70 vs. 2.11 ± 0.71, p &lt; 0.01) with a greater early diastolic E' (19.30 ± 4.06 vs. 18.18 ± 4.05 cm/s, p = 0.02). Greater LVMI and lower heart rate were independent predictors of elite endurance athletes [odds ratio (OR) and 95% confidence intervals: 1.03 (1.02, 1.04) and 0.96 (0.95, 0.98), respectively]. Greater LVMI, lateral mitral E'/A' ratio and right ventricular systolic pressure were independent predictors of elite strength athletes [OR: 1.03 (1.01, 1.05), 1.50 (1.06, 2.12), and 1.12 (1.05, 1.19), respectively].Conclusions: Cardiac structural and functional characteristics differ between endurance and strength elite athletes. While greater LVMI predicts elite status in both groups of Asian athletes, consistent with findings from Western elite athletes, greater diastolic function, and right ventricular systolic pressure characterize strength elite athletes, while lower heart rate at rest predicts endurance elite athletic status.

Fear and loathing in VR: the emotional and physiological effects of immersive games

Compared to traditional screen-based media, virtual reality (VR) generally leads to stronger feelings of presence. The current study aimed to investigate whether playing games in VR resulted in a stronger sense of presence than playing on a TV, and whether these feelings of presence affected players’ emotional and physiological responses to the games. Two experiments were conducted among 128 students, comparing the effects of playing either a survival horror game (N = 59) or a first-person shooter (N = 69) on a TV or in VR on physiological and subjective fear, hostility and enjoyment. Results showed that playing games in VR resulted in a stronger sense of presence, lower heart rate variability and a stronger subjective sense of fear. The feeling of presence thereby mediated the effects of VR on fear. The effects of playing a first-person shooter in VR on hostility were mixed, and gaming in VR was not more enjoyable than on TV. Regardless of the type of game or display medium, hostility increased significantly post-play. This study provides evidence that commercial VR games can affect feelings of presence and the physiological and emotional state of players.

BACKSTROKE TEACHING METHODS IN HEALTHY CHILDREN WITH RESIDUAL PRIMITIVE REFLEXES

There are studies suggesting that primitive reflexes can remain active in healthy children. Formal backstroke teaching is a part of many aquatic curriculum program. Even though the links with a problem during swimming learning with retained primitive reflexes were mentioned, there are no studies about effect of different backstroke teaching methods in healthy children with residual primitive reflexes. Aim of the study is to define the effect of teaching methods for backstroke in healthy children with residual primitive reflexes. Subjects: 6-7 years old healthy children with residual primitive reflexes. Methods: A part practice backstroke teaching method for the first group (12 children) has been focused on teaching of separate components (leg kicks, arm pulls, and breathing) before fitting them together, while another 12 participants in second group learnt backstroke separate components of arm-to-leg integration before combining them together inside of cycle. After 12 weeks of practice backstroke proficiency and heart rate during maximal continuous backstroke swimming were analyzed. The obtained results show significant differences between the two groups. The results of the second group are linked with better backstroke proficiency, significantly longer swimming distance and lower heart rate during swimming.

Lower Cardiovascular Reactivity Is Associated With More Childhood Adversity and Poorer Midlife Health: Replicated Findings From the Dunedin and MIDUS Cohorts

Cardiovascular reactivity has been proposed as a biomarker linking childhood adversity and poorer health. In the current study, we examined the association of childhood adversity, cardiovascular reactivity, and health in the Dunedin Multidisciplinary Health and Development Study ( n = 922) and Midlife in the United States (MIDUS) studies ( n = 1,015). In both studies, participants who experienced more childhood adversity had lower cardiovascular reactivity. In addition, people with lower cardiovascular reactivity had poorer self-reported health and greater inflammation. Dunedin participants with lower cardiovascular reactivity were aging biologically faster, and MIDUS participants with lower heart rate reactivity had increased risk of early mortality. Cardiovascular reactivity was not associated with hypertension in either study. Results were partially accounted for by greater reactivity among more conscientious, less depressed, and higher functioning participants. These results suggest that people who experienced childhood adversity have a blunted physiological response, which is associated with poorer health. The findings highlight the importance of accounting for individual differences when assessing cardiovascular reactivity using cognitive stressor tasks.

Resonance frequency is not always stable over time and could be related to the inter-beat interval

Heart Rate Variability Biofeedback (HRVB) is based on breathing at an optimal rate (or resonance frequency, RF) corresponding to the respiratory sinus arrhythmia (RSA). Our aim is to check whether the RF is a stable factor and analyse the HRV parameters individually per each breathing rate, comparing it with free slow breathing. A sample of 21 participants were trained in a test–retest HRVB protocol. The results indicated that RF changed between Test and Retest sessions in 66.7% of participants. This instability could be related to the average of interbeat interval (IBI). HRV time domain parameters (SDNN and RMSSD) were significantly higher for RF than for other breathing rates, including 6 breath/min and free slow breathing. Free slow breathing showed a lower heart rate averages than RF and other slow breathing rates. Overall, our study suggests the relevance of assessing RF individually and before each HRVB session, because the maximum cardiovascular benefits in terms of increasing HRV were found only at RF. Thus, breathing at the individualized and momentary frequency of resonance increases cardiac variability.

Risk Factors for Longitudinal Resting Heart Rate and Its Associations With Cardiovascular Outcomes in the DCCT/EDIC Study

<b>Background:</b> Individuals with diabetes have higher resting heart rate compared to those without, which may predict long-term cardiovascular (CVD) risk. Using data from the DCCT/EDIC study, we evaluated whether the beneficial effect of intensive vs. conventional diabetes therapy on heart rate persisted, the factors mediating the differences in heart rate between treatment groups, and the effects of heart rate on future CVD risk. <p><b>Research Design and Methods:</b> Longitudinal changes in heart rate, from annual electrocardiograms over 22 years of EDIC follow-up, were evaluated in 1402 participants with type 1 diabetes. Linear mixed models were used to assess the effect of DCCT treatment group on mean heart rate over time and Cox proportional hazards models were used to estimate the effect of heart rate on CVD risk during DCCT/EDIC. </p> <p><b>Results:</b> At DCCT closeout, participants were 33±7 years old, 52% male, diabetes duration 12±5 years, and HbA1c 7.4±1.2% (intensive) and 9.1±1.6% (conventional). Through EDIC, participants in the intensive group had significantly lower heart rate compared to the conventional group. While significant group differences in heart rate were fully attenuated by DCCT/EDIC mean HbA1c, higher heart rate predicted CVD and major adverse cardiovascular events (MACE) independent of other risk factors.<i> </i></p> <p><b>Conclusion:</b> After 22 years of follow-up, former intensive vs. conventional therapy remained significantly associated with lower heart rate, consistent with the long-term beneficial effects of intensive therapy on CVD. DCCT treatment group effects on heart rate were explained by differences in DCCT/EDIC mean HbA1c.</p>