Adjustment For Heart Rate Research Articles

Cardiac structure and function in people with cystic fibrosis

Abstract Background Cystic fibrosis (CF) is an autosomal recessive disease affecting multiple organs, however the extent of cardiac involvement in CF is yet to be determined. The remarkable therapeutic advancements with new highly effective CF transmembrane conductance regulator (CFTR) modulator treatment and subsequent increase in life expectancy substantiates further research. Purpose We aimed to explore the prevalence of abnormalities and potential subclinical alterations in cardiac structure and function in adults with CF compared to matched controls and investigate potential cardiovascular risk factors in people with CF (pwCF). Methods In this cross-sectional study, 104 adult pwCF in Denmark underwent clinical and echocardiographic examination. All participants were matched 1:1 with controls from the general population on age and sex. Uni- and multivariable linear regression models with adjustment for heart rate, FEV1, smoking status, hypertension and CF-related diabetes (CFRD) were used to test for differences in echocardiographic parameters between cases and controls. Abnormal cardiac function was defined as left ventricular ejection fraction (LVEF) <50%, left ventricular (LV) global longitudinal strain (GLS) < 16% or presence of diastolic dysfunction. Uni- and multivariable logistic regression models adjusted for age, sex, homozygous genotype, FEV1/FVC, BMI, smoking status, CFRD, pancreatic insufficiency, hypertension, and ischemic heart disease were performed to assess associations between potential risk factors and cardiac dysfunction in CF. Forest plots were constructed to visually represent the findings. Results Of 104 pwCF, 44% were female, mean age was 34 years, 93% received CFTR modulator treatment, and 91% had mutations with only minimal CFTR function (mutation class I-III). The prevalence of abnormal cardiac function in pwCF was 44% versus 22% in controls. Compared to controls, pwCF were found to have smaller LV dimensions, worse LV diastolic function, and more impaired right ventricle (RV) as well as LV systolic function (Table). After multivariable adjustment, LV diastolic function as well as LV and RV systolic function remained impaired in pwCF as compared to controls. Male sex and decreasing FEV1/FVC ratio remained independently associated with abnormal cardiac function in pwCF (male sex: OR 3.94 (1.56; 9.95), p=0.004 and FEV1/FVC ratio: OR 2.05 per 0.1 unit decrease (1.21; 3.52), p=0.008, respectively) (Figure). Conclusion Both left- and right-sided cardiac alterations were found in pwCF. After adjustments for potential risk factors, both RV and LV systolic measures remained altered in pwCF, compared to controls. Male sex and decreasing pulmonary function evaluated by FEV1/FVC-ratio were identified as factors associated with abnormal cardiac function in pwCF.Figure

Racial Differences in Age-Related Changes in Left Ventricular Structural and Functional Echocardiographic Measurements Among Healthy Japanese and American Participants - A Subanalysis of the World Alliance Society of Echocardiography Normal Values Study.

Age-related changes in left ventricular (LV) structure and function lower the threshold for the onset of heart failure with preserved ejection fraction (HFpEF). LV parameters change also with race; however, the racial differences in age-related changes in LV parameters with and without adjustment for body mass index (BMI), heart rate (HR), and blood pressure (BP) remain unclear. We performed a subanalysis of the World Alliance Society of Echocardiography Normal Values Study, an international cross-sectional study that examined normal echocardiographic values in 15 countries. The age-related changes in 2-dimensional echocardiographic derived parameters including LV size, systolic function, and mass, were compared between healthy Japanese (n=227) and healthy White (n=98) and Black (n=69) American participants. In men, age-related changes in all parameters did not differ significantly among races. However, compared with Japanese women, White American women had a smaller body surface area (BSA)-indexed LV volume, BSA-indexed LV internal dimension at end-systole, BSA-indexed LV stroke volume, and LV mass index to BSA, and a larger LV ejection fraction with age, even after adjusting for BMI, HR, and BP. Age-related changes in LV structure and function, which are important for the pathophysiology of HFpEF, may differ by race. Therefore, future studies examining echocardiographic reference values for each age group in each race are needed.

Chronotropic Incompetence Among People With HIV Improves With Exercise Training in the Exercise for Healthy Aging Study.

People with HIV (PWH) have lower exercise capacity than peers without HIV, which may be explained by chronotropic incompetence, the inability to increase heart rate during exercise. The Exercise for Healthy Aging Study included adults aged 50 to 75 years with and without HIV. Participants completed 12 weeks of moderate-intensity exercise, before randomization to moderate or high intensity for 12 additional weeks. We compared adjusted heart rate reserve (AHRR; chronotropic incompetence <80%) on cardiopulmonary exercise testing by HIV serostatus and change from baseline to 12 and 24 weeks using mixed effects models. Among 32 PWH and 37 controls (median age, 56 years; 7% female), 28% of PWH vs 11% of controls had chronotropic incompetence at baseline (P = .067). AHRR was lower among PWH (91% vs 101%; difference, 10%; 95% CI, 1.9%-18.9%; P = .02). At week 12, AHRR normalized among PWH (+8%; 95% CI, 4%-11%; P < .001) and was sustained at week 24 (+5%; 95% CI, 1%-9%; P = .008) versus no change among controls (95% CI, -4% to 4%; P = .95; interaction P = .004). After 24 weeks of exercise, 15% of PWH and 10% of controls had chronotropic incompetence (P = .70). Chronotropic incompetence contributes to reduced exercise capacity among PWH and improves with exercise training.

Sex differences in the age-related decrease of spontaneous baroreflex function in healthy individuals.

The baroreflex is a powerful physiological mechanism for rapidly adjusting heart rate in response to changes in blood pressure. Spontaneous baroreflex sensitivity (BRS) has been shown to decrease with age. However, studies of sex differences in these age-related changes are rare. Here we investigated several markers of spontaneous baroreflex function in a large sample of healthy individuals. Cardiovascular signals were recorded in the supine position under carefully controlled resting conditions. After quality control, n = 980 subjects were divided into five age groups [age < 30 yr (n = 612), 30-39 yr (n = 140), 40-49 yr (n = 95), 50-59 yr (n = 61), and >60 yr (n = 72)]. Spontaneous baroreflex function was assessed in the time domain (bradycardic and tachycardic slope) and in the frequency domain in the low- and high-frequency band (LF-α, HF-α) applying the transfer function. General linear models showed a significant effect of factor age (P < 0.001) and an age × sex interaction effect (P < 0.05) on each indicator of the baroreflex function. Simple main effects showed a significantly higher BRS as indicated by tachycardic slope, LF-α and HF-α in middle-aged women compared with men (30-39 yr) and higher LF-α, bradycardic and tachycardic slope in men compared with women of the oldest age group (>60 yr). Changes in BRS over the lifespan suggest that baroreflex function declines more slowly but earlier in life in men than in women. Our findings could be linked to age-related changes in major sex hormone levels, suggesting significant implications for diverse cardiovascular outcomes and the implementation of targeted preventive strategies.NEW & NOTEWORTHY In this study, we demonstrate that the age-related decrease of spontaneous baroreflex sensitivity is different in men and women by analyzing resting state cardiovascular data of a large sample of healthy individuals.

Abstract 15859: Cardiopulmonary Exercise Function in Methamphetamine-Associated Heart Failure

Introduction: The role of methamphetamine (meth) cessation in the functional recovery of methamphetamine-associated HF (meth-HF) is unknown. Objective To evaluate the role of active meth use on cardiopulmonary function in participants with meth-HF. Methods: We recruited participants from a longitudinal cohort study of meth-HF and used cardiopulmonary exercise testing (CPET) with maximal effort upright cycle ergometer to assess exercise cardiorespiratory function. Descriptive analysis was used to study associations between cardiopulmonary function and 1) active use and 2) ejection fraction (EF) recovery. Results: Of those assessed for eligibility (n = 55), 11 were deceased and 30 could not be contacted/declined participation. Ten studies were completed of the 14 scheduled, with three no-shows and one termination due to pre-test PVCs. Of those who completed studies, 90% were male, median age was 52 years [40, 54] and duration of HF was 33 months [16, 58]. Five were active users, and five had a recovered EF. All were on quad-guideline-directed medical therapy (GDMT) for a median duration of 15 months [9.1, 29]. Baseline EF was 28% [21, 42], and EF closest to CPET date was 50% [42, 59]. Peak VO 2 (% predicted) in prior vs. active use was 73 [66, 75] and 60 [48, 66]; in persistently low vs. recovered EF, it was 75 [66, 75] and 63 [60, 66] ( Figure 1A ). Adjusted heart rate reserve (aHRR, %) in prior vs. active use was 42 [37, 43] and 46 [44, 58]; in persistently low vs. recovered EF, it was 58 [44, 62] and 37 [35, 43] ( Figure 1B ). In prior vs. active use, VO 2 pulse (VO 2 /HR, mL/beat) was 16 [15, 17] and 13 [12, 15]. One participant died of sudden cardiac death between CPET and time of analysis. Conclusions: To our knowledge, this is the first study looking at cardiorespiratory fitness in the setting of meth use and HF. Our preliminary findings suggest that peak VO 2 and aHRR remain low, which suggests the presence of persistent cardiac effects of meth use despite cessation of use and/or recovery of EF.

Abstract 14771: Chronotropic Incompetence and Response to Exercise Training by HIV Status in the Exercise for Healthy Aging Study

Background: People with HIV (PWH) have lower exercise capacity compared to HIV-uninfected peers. Chronotropic incompetence (CI), the inability to increase heart rate during exercise, may contribute to reduced exercise capacity. We hypothesized that PWH would have lower adjusted heart rate reserve (AHRR=(HR peak -HR rest )/(220-Age-HR rest ), a measure of chronotropy, normal &gt;80%) and that AHRR would improve with exercise training. Methods: The Exercise for Healthy Aging Study included sedentary adults ages 50-75 with (PWH) and without HIV (controls) recruited for a 24-week exercise training program. Participants exercised at moderate intensity for weeks 1-12 and were then randomized to continue moderate or advance to a higher intensity of exercise for weeks 13-24. We compared prevalent CI on treadmill cardiopulmonary exercise testing by HIV. We compared AHRR and change in AHRR from baseline to 12 and 24 weeks by HIV status using mixed effects models. Finally we explored whether improved chronotropy could explain the greater benefit of exercise observed among PWH. Results: Among 32 PWH and 37 controls (median age 56, 7% female, mean BMI 28 mg/m 2 ), 9/31 (29%) with HIV compared to 4/38 (11%) controls had CI (p=0.07). At entry, AHRR was lower among PWH (91 vs 102%; difference 11%, 95%CI 2.5-19.7; p=0.01). At week 12, AHRR normalized among 27 PWH (+8%, 95%CI 4-11; p&lt;0.001) and sustained at week 24 (+5, 95%CI 1-9; p=0.008) compared to no change among 31 controls (95%CI -4 to 4; p=0.95; p interaction =0.004). Accounting for AHRR, the greater benefit of exercise observed among PWH at 12 weeks (peak VO 2 +1.5 ml/kg/min more than controls, 95%CI 0.1 to 2.9, p=0.04) was attenuated (0.4 ml/kg/min independent of AHRR, 95%CI -0.9 to 1.8; p=0.53). After 24 weeks of exercise, only 4/26 (15%) PWH met the definition for CI compared to 3/29 (10%) of controls (p=0.70). Conclusions: Chronotropic incompetence may contribute to reduced exercise capacity among PWH and improve with exercise training.

Association of SARS-CoV-2 Infection and Cardiopulmonary Long COVID With Exercise Capacity and Chronotropic Incompetence Among People With HIV.

Background Postacute sequelae of COVID-19 (PASC) and HIV are both associated with reduced exercise capacity, but whether SARS-CoV-2 or PASC are associated with exercise capacity among people with HIV (PWH) is unknown. We hypothesized that PWH with PASC would have reduced exercise capacity from chronotropic incompetence. Methods and Results We conducted cross-sectional cardiopulmonary exercise testing within a COVID recovery cohort that included PWH with and without prior SARS-CoV-2 infection and people without HIV with prior SARS-CoV-2 infection (controls). We evaluated associations of HIV, SARS-CoV-2, and PASC with exercise capacity (peak oxygen consumption) and chronotropy (adjusted heart rate reserve). We included 83 participants (median age, 54 years; 35% women; 37 PWH): 23 out of 37 (62%) PWH and all 46 controls had prior SARS-CoV-2 infection, and 11 out of 23 (48%) PWH and 28 out of 46 (61%) without HIV had PASC. Peak oxygen consumption was reduced among PWH versus controls (80% predicted versus 99%, P=0.005), a difference of 5.5 mL/kg per minute (95% CI, 2.7-8.2; P<0.001). Chronotropic incompetence was more prevalent among PWH (38% versus 11%, P=0.002), with lower adjusted heart rate reserve (60% versus 83%, P<0.0001) versus controls. Among PWH, SARS-CoV-2 coinfection and PASC were not associated with exercise capacity. Chronotropic incompetence was more common among PWH with PASC: 7 out of 11 (64%) with PASC versus 7 out of 26 (27%) without PASC (P=0.04). Conclusions Exercise capacity and chronotropy are lower among PWH compared with individuals with SARS-CoV-2 infection without HIV. Among PWH, SARS-CoV-2 infection and PASC were not strongly associated with reduced exercise capacity. Chronotropic incompetence may be a common underrecognized mechanism of exercise intolerance among PWH, especially those with cardiopulmonary PASC.

VASODILATION IS THE PREDOMINANT FACTOR OF BLOOD PRESSURE LOWERING DURING DEVICE-GUIDED SLOW BREATHING– ANALYSIS BY WAVE SHAPE PARAMETERS OF PULSE WAVE ANALYSIS

Objective: There is evidence that device-guided slow breathing with direct biofeedback of pulse arrival time (PAT) leads to favorable changes (increase) in PAT and blood pressure (decrease). Slow breathing modulates peripheral blood flow and may decrease blood pressure by vasodilation. The objectives of the study presented here was to identify hemodynamic mechanisms of the blood pressure lowering effect of device-guided breathing observed in a previously published study (Mengden Blood Pressure Monitoring 2023). Design and method: Patients with a systolic BP 130-160 mmHg or treated essential hypertension (21 females / 23 males) were trained to perform repeated and unattended device guided slow breathing exercises for 10 minutes and 5 minutes cool down over 5 days. Furthermore, they were skilled to perform a self-measurement of blood pressure before and after the breathing exercise using a validated upper-arm device. A simple device was used to measure pulse arrival time by electrocardiography and photoplethysmography connected with a smartphone or tablet to provide biofeedback. Using pulse wave analysis, time to systolic peak (tsys) and time to dicrotic notch (tnotch) were measured and normalized to RR interval, i.e., as tsys / tT and tnotch / tT. Results: Oscillometric self measured blood pressure showed a reproducible decrease in systolic blood pressure of 5 mmHg (p&lt;0.01, SD 8 mmHg). Absolute tsys increased by 13ms (p&lt;0.001, SD 36 ms) and relative tsys / tT increased by 0.013 (p&lt;0.001, SD 0.033) by the end of the exercise compared to baseline after cooling down (15 min). Similarly absolute tnotch increased by 11ms (p&lt;0.001, SD 31 ms) as well as relative tnotch / tT in total by 0.011 (p&lt;0.001, SD 0.036) compared to baseline. Conclusions: The delayed arrival of the first pulse wave maximum and the prolonged ejection time after adjustment for heart rate can be assumed here as a surrogate of a decreasing afterload. It is thus evident from this perspective that vasodilation is an important factor of blood pressure lowering during device-guided breathing.

A Physiological Control for Artificial Heart Pump based on Adaptive Regulation of Heart Rate and the improved BAS Algorithm Optimization

In order to solve the problem that the traditional artificial heart pump has poor dynamic bionic performance and cannot respond to blood perfusion in real time according to the patient’s state, this paper proposes a new physiological control method based on adaptive adjustment of heart rate. Firstly, a coupled model of the cardiovascular circulatory system and artificial heart pump was established, and the correctness of the model is verified by hemodynamic simulation. Secondly, according to the model-free adaptive control theory, the artificial heart pump physiological control strategy for adaptive regulation of heart rate is designed, including pseudo partial derivative estimation algorithm and adaptive control law. Then, the parameters of the adaptive controller are optimized by the improved beetle antennae search algorithm. Finally, the auxiliary effect and dynamic performance of the adaptive control strategy are studied by numerical methods. The results show that the physiological control method based on adaptive regulation of heart rate realizes the adaptive modulation of heart rate and blood flow, which can meet the needs of blood perfusion in different states and help to promote the recovery of damaged heart.

Performance of heart rate adjusted heart rate variability for risk stratification of sudden cardiac death

PurposeAs a non-invasive tool for the assessment of cardiovascular autonomic function, the predictive value of heart rate variability (HRV) for sudden cardiac death (SCD) risk stratification remains unclear. In this study, we investigated the performance of the individualized heart rate (HR) adjusted HRV (HRVI) for SCD risk stratification in subjects with diverse risks.MethodsA total of 11 commonly used HRV metrics were analyzed in 192 subjects, including 88 healthy controls (low risk group), 82 hypertrophic cardiomyopathy (HCM) patients (medium risk group), and 22 SCD victims (high risk group). The relationship between HRV metrics and HR was examined with long-term and short-term analysis. The performance HRVI was evaluated by area under the receiver operating characteristic curve (AUC) and covariance of variation (CV).ResultsMost of the HRV metrics were exponentially decayed with the increase of HR, while the exponential power coefficients were significantly different among groups. The HRVI metrics discriminated low, medium and high risk subjects with a median AUC of 0.72[0.11], which was considerably higher than that of the traditional long-term (0.63[0.04]) and short-term (0.58[0.05]) HRV without adjustment. The average CV of the HRVI metrics was also significantly lower than traditional short-term HRV metrics (0.09 ± 0.02 vs. 0.24 ± 0.13, p < 0.01).ConclusionsSubjects with diverse risks of SCD had similar exponential decay relationship between HRV metrics and HR, but with different decaying rates. HRVI provides reliable and robust estimation for risk stratification of SCD.

The Time Course of Cardiorespiratory Adaptations to Rowing Indoor Training in Post-Menopausal Women.

Post-menopausal women have impaired cardiorespiratory responses to exercise compared to young women. Exercise training may counterbalance impairments, but the time-dependent effects of exercise training remain unclear. The current study aims to investigate the effects of rowing training on maximal aerobic capacity and time-course cardiorespiratory adaptations in older women. Female participants (n = 23) were randomly allocated to the experimental group (EXP; n = 23; 66 ± 5 years old) enrolled in rowing exercise training and control group (CON; n = 10; 64 ± 4 years old). The cardiopulmonary exercise test (CET) was performed in a cycle ergometer pre- and post-interventions. Oxygen uptake (VO2), stroke volume (SV), cardiac output (CO), and HR were recorded during CET and analyzed at the peak of the exercise. HR was monitored during exercise recovery, and the index of HRR was calculated by ΔHRR (HRpeak-HR one-minute recovery). Every two weeks, Rowing Stepwise Exercise (RSE) in a rowing machine was performed to track specific adaptations to the exercise modality. HR was continuously recorded during RSE and corrected for the average power of each step (HR/watts). The rowing training protocol consisted of three weekly sessions of 30 min at an intensity corresponding to 60-80% of peak HR for ten weeks. Rowing exercise training increased VO2, SV, and CO at the peak of the CET, and ΔHRR. Increased workload (W) and reduced HR response to a greater achieved workload (HR/W) during RSE were observed after six weeks of training. Rowing exercise training is a feasible method to improve cardiorespiratory performance, vagal reactivation and heart rate adjustments to exercise in older women.

Predictors of mitral valve haemodynamics after mitral valve repair for degenerative mitral regurgitation

ObjectiveIntraoperative predictors of functional mitral valve (MV) stenosis after surgical repair of mitral regurgitation (MR) caused by prolapse remain poorly characterised. This study evaluated the effect of annuloplasty size on...

Comparing the effect of body wash with marshmallow plant and lukewarm water on reducing the temperature of febrile children: a randomized clinical trial

BackgroundFever is the most common reason for children’s visits to medical centers. Its management is an essential duty of a pediatric nurse. The aim of this study was to determine the effect of body wash with Marshmallow plant on children’s fever.MethodsThis parallel clinical trial was performed on 92 children aged 6 months to 10 years with a tympanic temperature above 38.3 °C. Participants were randomly assigned to groups. Simultaneously with receiving acetaminophen, body wash was performed in the control group with lukewarm water and in the intervention group with white Marshmallow extract. The children’s temperature; from the beginning of the study was checked and recorded every 15 min in the first hour and in the 4th and 6th hours. The time duration to resolve fever, the frequency of afebrile children at different times of the study, and the value of temperature reduction were primary outcomes. Heart rate, the need to administer the next dose of acetaminophen, and the time of fever recurrence were recorded as secondary outcomes.ResultsThe mean time duration to resolve fever in the intervention group was shorter than in the control group (B = 8.181, 95% CI 3.778–12.584, p < 0.001). The frequency of the children without fever was higher in the intervention group during different times of the study (p < 0.001). The mean value of temperature reduction in the intervention group was higher than the control group (B = -0.27 °C, 95% CI: -0.347 to -0.193, P < 0.001), although, after adjusting the effect of confounding variables it was not significant (P = 0.127). The mean of adjusted heart rate change (p = 0.771), the time of fever recurrence (P = 0.397), and the frequency of children requiring the next dose of acetaminophen (p = 0.397) did not show a significant difference between the groups.ConclusionBody wash with Marshmallow extract reduced children’s fever in a shorter period of time and to some extent a greater extent than the control group without side effects. Therefore, it can be used as an effective and safe complementary method to help reduce fever. However, more studies are necessary for this field.Trial registrationRegistration in Iranian Clinical Trials (RCTs) on 31.08.2020 with registration code: IRCT20200809048345N1.

Abstract 10570: Inflammation During Early Post-Acute Covid-19 is Associated With Reduced Exercise Capacity and Long Covid Symptoms After 1 Year

Introduction: Mechanisms underlying cardiopulmonary symptoms following SARS-CoV-2 infection (post-acute sequelae of COVID-19 “PASC” or “Long COVID”) remain unclear. The purpose of this study was to elucidate the pathophysiology of PASC using cardiopulmonary exercise testing (CPET), cardiac magnetic resonance imaging (CMR) and ambulatory rhythm monitoring. Methods: We performed CMR, CPET, and ambulatory rhythm monitoring among adults &gt; 1 year after confirmed SARS-CoV-2 infection in the UCSF Long-Term Impact of Infection with Novel Coronavirus cohort (LIINC; NCT04362150) and correlated findings with previously measured biomarkers. We used logistic regression to estimate associations with PASC symptoms and linear regression to estimate differences by symptoms adjusted for confounders. Results: Out of 120 participants, 46 participants (unselected for symptom status) had cardiac testing performed at median 17 months after infection. Median age was 52, 18 (39%) were female, and 6 (13%) were hospitalized for severe acute infection. On CPET (n=39), 13/23 (57%) with symptoms had reduced exercise capacity (peak VO2&lt;85% predicted) compared to 2/16 (13%) without symptoms (p=0.008). Adjusted peak VO 2 was 5.9 ml/kg/min lower (-9.6 to -2.3; p=0.002) or -21% predicted (-35 to -7; p=0.006) among those with symptoms. Chronotropic incompetence was present among 9/15 (60%) with reduced peak VO2 (adjusted heart rate reserve&lt;80%: OR 15.6 for reduced peak VO2, 95%CI 1.30-187; p=0.03). Inflammatory markers (hsCRP, IL-6, TNF-α) and SARS-CoV-2 antibody levels measured early in PASC (median 3.5-6 months after infection) were negatively correlated with peak VO2 more than 1 year later (Figure). Conclusions: Cardiopulmonary symptoms and elevated inflammatory markers present early in PASC are associated with reduced exercise capacity during CPET &gt;1 year following COVID-19. Chronotropic incompetence may explain reduced exercise capacity among some individuals with PASC.

Cardiovascular reflexes relevant to veterinary anaesthesia

Cardiovascular reflexes can be defined as fast-acting, centrally-mediated feedback mechanisms between the cardiovascular system and the central nervous system. These reflexes help to maintain blood pressure within physiological limits by adjusting heart rate, cardiac contractility and systemic vascular resistance. Several cardiovascular reflexes have been identified in mammals, including the baroreceptor, the chemoreceptor, the Bainbridge and the Bezold-Jarisch reflexes. Under general anaesthesia, several factors can trigger or attenuate cardiovascular reflexes; therefore, it is important to understand their pathophysiological mechanisms. This article reviews the physiology of four of the main cardiovascular reflexes, focusing on their relevance to veterinary anaesthesia.

Complexity and heart rate adjustments of diabetic people during isometric contraction.

Type 2 Diabetes Mellitus (DM2) can lead to autonomic nervous system dysfunction and heart rate variability (HRV) is often used to assess this system both during rest and during physical exercise. To evaluate the autonomic modulation at rest and the responses of heart rate and parasympathetic indices of individuals with DM2 to isometric handgrip exercise. The sample consisted of individuals of both sexes; over 40 years, divided into groups, with and without DM2 diagnosis. The collection of resting HRV was performed for 20 minutes in the supine position, and 256 points were selected for symbolic and linear analysis. The individuals performed isometric contraction for one minute with intensities of 10, 20, 30, 40 and 50 % of the maximum contraction, using the parasympathetic indexes RMSSD and SD1 for analysis. Linear and symbolic indices of HRV at rest and those obtained during exercise were similar (p-value>0.05). No association was found between the indices at rest and the responses to exercise, with a slight delay in the response of diabetics in HR and parasympathetic indices being identified. There was no difference between the groups in the modulation of rest or in the parasympathetic adjustments of the exercise (Tab. 4, Ref. 32).

Cardiovascular autonomic nervous function in 7–12 years old children conceived naturally or by ART with frozen and fresh embryo transfer

Abstract Background Cardiovascular autonomic nervous functions (CANF) exert important homeostatic mechanisms to prevent major arterial blood pressure fluctuations by adjusting heart rate (HR), cardiac contractility, and peripheral vascular tone. Children conceived by assisted reproductive technologies (ART) are at risk of increased carotid intima-media thickness, insulin resistance, arterial stiffness, and hypertension. CANF is impaired in children with obesity and diabetes mellitus, and conductance artery stiffness is documented to influence CANF. CANF may therefore be hypothetized to be impaired in children conceived by ART. Purpose This is the first study to investigate whether children conceived by ART have impaired CANF as compared to naturally conceived children. Method CANF was studied in 105 singletons aged 7–12 years conceived naturally (NC, N=33) or by ART (frozen embryo transfer (FET, N=34) and fresh embryo transfer (Fresh ET, N=38)). CANF was evaluated with continuous non-invasive hemodynamic measurements (Finapres®) by the HR and blood pressure changes seen relative to rest during active standing, deep breathing and Valsalva, respectively. Results The descriptive data showed no difference in CANF measurements between our study groups (Table 1). In the multivariate analysis, only the Valsalva HR-ratio to rest was significantly higher in children conceived by FET as compared to NC children after adjustments for age, sex, BMI and maternal age at delivery (Figure 1). For all meaures, the effect size (Hedges d) ranged from 0.02 to 0.48. Conclusion In this study only the Valsalva HR-response between FET and NC groups were statistically significant after adjustment for confounders, and in general effect sizes were small. Our study suggests that children conceived by ART do not have a significantly impaired cardiovascular autonomic nervous function as compared to naturally conceived children. Funding Acknowledgement Type of funding sources: Foundation. Main funding source(s): Novo Nordisk Foundation

Effect of a standardized maternal meal on fetal middle cerebral artery Doppler indices: A single-blinded crossover study.

ObjectiveMeasures of Doppler blood flow velocity profiles are an integral part of monitoring fetal well-being during pregnancy. These examinations are performed at different times of the day and at different maternal meal states. In uncomplicated pregnancies, we assessed the effect of a standardized maternal meal on middle cerebral artery (MCA) and umbilical artery (UA) Doppler blood flow velocity pulsatility indices (PIs) and MCA peak systolic velocity (PSV).MethodsIn this prospective single-blinded crossover study 25 healthy women were examined at 36 weeks of pregnancy. The first examination was performed in the morning following overnight fast, and repeated after extended fast (state A), and after a standard breakfast meal (state B).ResultsIrrespective of maternal prandial status, the MCA-PI values were lower in the 2nd compared to the 1st examination (-0.187; p = 0.071, and -0.113; p = 0.099, state A and B, respectively). Compared to the values in the 1st examination, the UA-PI values, were higher after extended fast (0.014; p = 0.436), and lower post-prandially (-0.036; p = 0.070). The difference (state B minus state A) between the meal states were not significant (0.074; p = 0.487 and -0.050; p = 0.058, for MCA-PI and UA-PI, respectively). Adjusting for the possible influence of fetal heart rate on MCA-PI and UA-PI, the differences between meal states remained non-significant (p = 0.179, p = 0.064, respectively). The MCA-PSV values increased after the meal (6.812; p = 0.035), whereas no increase was observed following extended fast (0.140; p = 0.951). The difference in MCA-PSV values between the two meal states was not significant (6.672; p = 0.055).ConclusionOur results demonstrate possible diurnal variations in MCA-PI and UA-PI, with and without adjustment for fetal heart rate, that seem to be unaffected by maternal meal intake in healthy pregnancies.

P-772 Cardiovascular autonomic nervous function in singletons conceived after ART with frozen and fresh embryo transfer compared to naturally conceived children

Abstract Study question Do children conceived after assisted reproductive technologies (ART) with frozen or fresh embryo transfer have altered cardiovascular autonomic nervous function compared to naturally conceived children? Summary answer Cardiovascular autonomic nervous function was comparable in singletons conceived after ART with frozen or fresh embryo transfer, and naturally conceived children. What is known already Cardiovascular autonomic nervous function (CANF) exert important homeostatic mechanisms to prevent major arterial blood pressure fluctuations by adjusting heart rate, cardiac contractility, and peripheral vascular tone. CANF is impaired in children with obesity and diabetes mellitus, and conductance artery stiffness is documented to influence CANF. Previous studies have reported that children conceived after ART are at risk of increased carotid intima-media thickness; insulin resistance; arterial stiffness; and hypertension. This is the first study to investigate CANF in children conceived after ART. Study design, size, duration CANF was studied in 110 singletons aged 7-12 years conceived after frozen embryo transfer (FET, N = 35), fresh embryo transfer (fresh-ET, N = 39) or natural conception (NC, N = 36). Children were born between 2009 and 2013. This study was conducted between June 2019 and October 2021. Participants/materials, setting, methods Participants were identified through the Danish IVF and Medical Birth Registries. CANF was evaluated by heart rate (HR) changes (ratio to rest) during deep breathing; Valsalva; and active stand test with continuous non-invasive hemodynamic measurements. Anthropometric measures, fasting blood samples, and maternal questionnaires were collected. Neonatal and maternal pregnancy data were collected from the Medical Birth Registry. Children with a history of congenital heart disease or mothers with gestational diabetes or diabetes mellitus were excluded. Main results and the role of chance A total of 110 singletons with a median age of 9.0 years were included in this study. We found no significant associations between conception method and our measures of CANF. For FET, fresh-ET, and NC, respectively, the HR-ratio for deep breathing was 1.62 (0.2 SD), 1.62 (0.16) and 1.63 (0.17) (ANOVA-P = 0.97). For Valsalva, the HR-ratio was 1.97 (0.4), 1.88 (0.41) and 1.63 (0.17), respectively (ANOVA-P = 0.24). For the active stand test, the HR-ratio was 1.43 (0.17), 1.41 (0.2) and 1.43 (0.19), respectively (ANOVA-P = 0.91). Associations remained non-significant after adjustment for age, sex, body surface area, body mass index, and mean arterial pressure. In the multivariate analysis, several other factors were significantly associated with HR-ratio for deep breathing: age (β = -0.06, P = 0.03), body surface area (β = 0.79, P = 0.01), body mass index (β = -0.03, P = 0.04), and mean arterial pressure (β =-0.01, P = 0.03), but not with other measures of CANF. All data for CANF were within reference limits. Also, mothers in the ART groups were older at childbirth than NC group as expected. No significant differences were observed in clinical characteristics, including neonatal and other maternal data. Limitations, reasons for caution This study is limited by its observational design to draw any firm conclusion on causality. Also, it is a limitation that the pubertal status was not systematically assessed as pubertal hormones may play a role in CANF. Wider implications of the findings This study contributes to the current knowledge about cardiovascular health risks in ART children. Reassuringly, this study found that children conceived after ART (frozen or fresh-ET) did not exhibit impaired cardiovascular autonomic nervous function compared to naturally conceived children. Trial registration number NCT03719703

The Relevance of Heart Rate Fluctuation When Evaluating Atrial Substrate Electrical Features in Catheter Ablation of Paroxysmal Atrial Fibrillation.

Coronary sinus (CS) catheterization is critical during catheter ablation (CA) of atrial fibrillation (AF). However, the association of CS electrical activity with atrial substrate modification has been barely investigated and mostly limited to analyses during AF. In sinus rhythm (SR), atrial substrate modification is principally assessed at a global level through P-wave analysis. Cross-correlating CS electrograms (EGMs) and P-waves’ features could potentiate the understanding of AF mechanisms. Five-minute surface lead II and bipolar CS recordings before, during, and after CA were acquired from 40 paroxysmal AF patients. Features related to duration, amplitude, and heart-rate variability of atrial activations were evaluated. Heart-rate adjustment (HRA) was applied. Correlations between each P-wave and CS local activation wave (LAW) feature were computed with cross-quadratic sample entropy (CQSE), Pearson correlation (PC), and linear regression (LR) with 10-fold cross-validation. The effect of CA between different ablation steps was compared with PC. Linear correlations: poor to mediocre before HRA for analysis at each P-wave/LAW (PC: max. +18.36%, p = 0.0017, LR: max. +5.33%, p = 0.0002) and comparison between two ablation steps (max. +54.07%, p = 0.0205). HRA significantly enhanced these relationships, especially in duration (P-wave/LAW: +43.82% to +69.91%, p < 0.0001 for PC and +18.97% to +47.25%, p < 0.0001 for LR, CA effect: +53.90% to +85.72%, p < 0.0210). CQSE reported negligent correlations (0.6–1.2). Direct analysis of CS features is unreliable to evaluate atrial substrate modification due to CA. HRA substantially solves this problem, potentiating correlation with P-wave features. Hence, its application is highly recommended.