Impaired cardiorespiratory coupling in young normotensives with a family history of hypertension

The Association Between Body Mass Index and Parental History of Hypertension Among Young Indian Adults

BACKGROUND

Hypertension is a disease of multifactorial etiology. Individuals with parental history of hypertension (PHH) have also been observed to be at an increased risk of developing hypertension in their adult life. However, there is a dearth of studies among youth. Obesity is one of the risk factors, and studies conducted among adults of all age groups have observed that there is a highly significant correlation between hypertension and body mass index (BMI). Hence, the association between the two factors, viz., parental history of hypertension and BMI, among the young Indian male and female population was analyzed in this study.

METHOD

This cross-sectional study conducted in Central India comprised 100 young adults between 18 and 25 years of age. On the basis of parental history of hypertension, the subjects were divided into two groups: group 1 comprised youth with parental history of hypertension and group 2 comprised youth without parental history of hypertension, involving 32 and 68 subjects in each of these groups, respectively. Anthropometric measurements were done using standard methods, and BMI was calculated. Statistical analysis was done using Epi Info software.

RESULTS

The study subjects in both groups were comparable in age. The mean age of the study participants was 19.32 years and 19.45 years in group 1 and group 2, respectively. The study did not find any association between BMI and parental history of hypertension.

CONCLUSION

The association between parental history of hypertension and BMI, the non-modifiable and modifiable independent risk factors, respectively, needs to be further explored in light of the iceberg phenomenon, multifactorial causation, and natural history of disease. It is worth mentioning that parental history of hypertension and other risk factors should be considered even if the BMI is normal as per Asian Indian cutoff levels.

HRV-Guided Training for Elders after Stroke: A Protocol for a Cluster-Randomized Controlled Trial

There are many consequences associated with having a stroke, all of which are important factors affecting long-term rehabilitation outcomes; these become important health issues for those of advanced age and require dedicated health strategies. High-intensity interval training (HIIT) is an effective training protocol used in cardiac rehabilitation programs; however, owing to the inter-individual variability in physiological responses to training associated with cardiovascular diseases, the exercise regimen given to each patient should be closely controlled and individualized to ensure the safety and efficiency of the exercise program. Heart rate variability (HRV) is currently being used for this purpose, as it is closely linked to parasympathetic nervous system activation, with high HRV scores associated with good cardiovascular adaptation. The objective of this protocol is to determine the effect of HIIT compared to HRV-guided training in terms of cardiorespiratory fitness, heart rate variability, functional parameters, body composition, quality of life, inflammatory markers, and cognitive function in patients who have had a stroke, as well as to assess the feasibility of patients undertaking an 8-week cardiac rehabilitation program, evaluating its safety and their adherence. The proposed protocol involved cluster-randomized controlled design in which the post-stroke patients are assigned either to an HRV-based training group (HRV-G) or a HIIT-based training group (HIIT-G). HIIT-G will train according to a predefined training program, whereas HRV-G will train depending on the patients' daily HRV. The outcomes considered are peak oxygen uptake (VO_2peak), endothelial and work parameters, heart rate variability, functional parameters, relative weight and body fat distribution, quality of life, inflammatory markers and cognitive function, as well as exercise adherence, feasibility, and safety. It is expected that this HRV-guided training protocol will improve functional performance in patients following a stroke and be safer, more feasible, and generate improved adherence relative to HIIT, providing an improved strategy for to optimize cardiac rehabilitation interventions.

Influence of family history of hypertension on blood pressure and heart rate variability in young adults: a meta-analysis

PURPOUSE

This meta-analysis evaluates the impact of family history of hypertension (FHH + ) on blood pressure (BP) and heart rate variability (HRV) in young adults.

METHODS

Observational studies that evaluated adults (aged between 18 and 40 years) of both sexes, are without cardiometabolic disease diagnosis, are published in English, and are reporting on the influence of FHH + (father, mother, or both) on BP and HRV were included. In June 2021, we made a search of the electronic database MEDLINE (accessed by PubMed). Random-effects models were used, and data are reported as standardized mean difference and 95% confidence limits.

RESULTS

Thirty-eight studies with a total of 2025 individuals were included. Clinic systolic [3.13 mmHg (1.75-4.51)] and diastolic [2.85 mmHg (1.65-4.04)] BPs were higher ( P < 0.001) in individuals with an FHH + . Only 24-h systolic BP was higher [1.76 mmHg (0.05-3.47); P = 0.04] in individuals with an FHH + . As for HRV indices in time-domain, RMSSD: -7.00 ms (-10.75 to -3.26), SDNN: -13.93 ms (-23.56 to -4.30), and HF [-6.82 n. u. (-9.76 to -3.89)] were lower ( P < 0.05), and LF [4.78 ms (2.52-7.03)] and LF/HF ratio [0.32 (0.14-0.50)] were higher ( P < 0.001) in individuals with an FHH + .

CONCLUSION

FHH + negatively impacts BP and HRV in young adults.

Cardiorespiratory coupling strength in athletes and non-athletes

PURPOSE

Despite the relevant presence of nonlinear components on heart period (HP) likely due to cardiorespiratory coupling (CRC), the HP is frequently analyzed in absence of concomitant recordings of respiratory movements (RESP). This study aims to assess the cardiovascular dynamics and CRC during postural challenge in athletes and non-athletes via joint symbolic analysis (JSA).

METHODS

A cross-sectional study was conducted in 50 men, aged between 20 and 40 yrs, divided into athletes (n = 25) and non-athletes (n = 25) groups. The electrocardiogram, blood pressure and RESP signals were recorded during 15 min in both supine position (REST) and after active postural maneuver (STAND). From the beat-to-beat series of HP, systolic arterial pressure (SAP) and RESP, we computed the time and frequency domain indexes and baroreflex sensitivity. The JSA was based on the definition of symbolic HP and RESP patterns and on the evaluation of the rate of their simultaneous occurrence in both HP and RESP series.

RESULTS

The JSA analysis was able to identify higher CRC strength at REST in athletes. Moreover, the response of CRC to STAND depended on the time scales of the analysis and was much more evident in athletes than in non-athletes, thus indicating a more reactive autonomic control in athletes.

CONCLUSION

Assessing CRC in athletes via JSA provides additional information compared to standard linear time and frequency domain tools likely due to the more relevant presence of nonlinearities in HP-RESP variability relationship.

Cardiorespiratory Phase Synchronization in Elderly Patients with Periodic and non-Periodic Breathing Patterns

Cardiorespiratory Phase Synchronization (CRPS) is the manifestation of the non-linear coupling between the cardiac and the respiratory systems, different to the Respiratory Sinus Arrythmia (RSA). This takes place when the heartbeats occur at the same relative phase of the breathing, during a succession of respiratory cycles. In this study, we investigated the CRPS in 45 elderly patients admitted to the semi-critical unit of a hospital. The patients were classified according to their respiratory state as non-Periodic Breathing (nPB), Periodic Breathing (PB) and Cheyne-Stokes Respiration (CSR). The phase synchrogram between the electrocardiographic and respiratory signals was computed using the Hilbert transform technique. A continuous measure of the CRPS was obtained from the synchrogram, and was characterized by the average duration of synchronized epochs (A vgDurSync), the percentage of synchronized time (%Sync), the number of synchronized epochs (NumSync), and the frequency ratio between the cardiac and respiratory oscillators (FreqRat). These measures were studied using two different thresholds (0.1 and 0.05) for the amplitude of the synchronization and a minimum duration threshold of 10s. According to the results, the AvgDurSync and %Sync had a decreasing trend in patients with breathing periodicity. In addition, CSR patients presented the lowest values A vgDurSync and %Sync. Therefore, the CRPS method could be a useful tool for characterizing periodic respiratory patterns in elderly patients, which might be related to chronic heart failure. Clinical Relevance- This study analyzes the synchronization between cardiac and respiratory systems in elderly patients with a possible progressive decompensation in the cardiac function.

Time-evolving coupling functions for evaluating the interaction between cerebral oxyhemoglobin and arterial blood pressure with hypertension

PURPOSES

This study aimed to investigate the network coupling between arterial blood pressure (ABP) and changes in cerebral oxyhemoglobin concentration (Δ [O₂ Hb]/Δ [HHb]) oscillations based on dynamical Bayesian inference in hypertensive subjects.

METHODS

Two groups of subjects, consisting of 30 healthy (Group Control, 55.1 ± 10.6 y), and 32 hypertensive individuals (Group AH, 58.9 ± 8.7 y), participated in this study. A functional near-infrared spectroscopy system was used to measure the Δ [O₂ Hb] and Δ [HHb] signals in the bilateral prefrontal cortex (LPFC/RPFC), motor cortex (LMC/RMC), and occipital lobe (LOL/ROL) during the resting state (12 min). Based on continuous wavelet analysis and coupling functions, the directed coupling strength (CS) between ABP and cerebral hemoglobin was identified and analyzed in three frequency intervals (I: 0.6-2 Hz, II: 0.145-0.6 Hz, III: 0.01-0.08 Hz). The Pearson correlations between the CS and blood pressure parameters were calculated in the hypertension group.

RESULTS

In interval I, Group AH exhibited a significantly higher CS for the coupling from ABP to Δ [O₂ Hb] than Group Control in LMC, RMC, LOL, and ROL. In interval III, the CS from ABP to Δ [O₂ Hb] in LPFC, RPFC, LMC, RMC, LOL, and ROL was significantly higher in Group AH than in Group Control. For the patients with hypertension, diastolic blood pressure was negatively and pulse pressure was positively related to the CS from ABP to Δ [O₂ Hb] oscillations in interval III.

CONCLUSIONS

The higher CS from ABP to Δ [O₂ Hb] in interval I indicated that the components of cardiac activity in cerebral hemoglobin oscillations were more directly responsive to the changes in systematic ABP in patients with hypertension than in healthy subjects. Meanwhile, the higher CS from ABP to Δ [O₂ Hb] in interval III indicated that the cerebral hemoglobin oscillations were susceptible to changes in blood pressure in hypertensive subjects. The results may serve as evidence of impairment in cerebral autoregulation after hypertension. The Pearson correlation results showed that diastolic blood pressure and pulse pressure might be regarded as predictors of cerebral autoregulation function in patients with hypertension, and may be useful for hypertension stratification. This study provides novel insights into the interaction mechanism between ABP and cerebral hemodynamics and could help in the development of new assessment techniques for cerebral vascular disease.

Role of the prefrontal lobe in young normotensives with a family history of hypertension and hypertensives

Accumulating evidence has demonstrated a significant relationship between prefrontal lobe and hypertension. Elevated blood pressure is usually associated with a prefrontal hemodynamic abnormality. However, the detailed process is still unclear. In this study, we designed a startle protocol and tested the response of the cerebral cortex and cardiovascular system in young normotensive subjects with a family history of hypertension (FH+). Additionally, the cold forehead test (CFT) was performed in hypertensive subjects. In total, 40 young normotensive subjects (21 with FH+ and 19 without a family history of hypertension (FH-)) and 49 middle-aged subjects (21 normotensives (NT) and 28 hypertensives (HT)) were recruited. Our results showed that the magnitude of startle-evoked alpha oscillation at the parasympathetic-related prefrontal cortex (FP1 and FP2) in the FH+ group was significantly smaller than in the FH- group. Acute bradycardia (RRI increase) was observed in FH- subjects but disappeared in the FH+ group. The coupling between instant cardiac acute response (increased RRI) and prefrontal arousal (magnitude of evoked oscillation) was significantly weakened in the FH+ group compared with the FH- group. Furthermore, the decrease in HR induced by parasympathetic outflow during CFT was absent in HT subjects. Hence, we concluded that the impairment of parasympathetic outflow derived from the prefrontal lobe occurs in both healthy young offspring of hypertensive and hypertensive patients.