Clinical Physiology and Functional Imaging最新文献

This study aimed to assess the association between brain glucose metabolism, measured using 2-deoxy-2-[18F]fluoro-d-glucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT), and heart rate variability (HRV). A total of 101 healthy men were included. Each participant underwent the following assessments: (1) brain ¹⁸F-FDG PET, (2) anthropometric measurements, and (3) HRV test. PET scans were spatially normalised to MNI space using PET templates from SPM5 with pmod. An Automated Anatomical Labelling 2 atlas was used to define regions of interest (ROIs). For each ROI, the mean uptake was normalised to the individual's global cortical mean uptake, yielding a standardised uptake value ratio (SUVR). After logarithmic transformation of the regional SUVR, the effects of the root mean square of successive differences (RMSSD) on the regional SUVR were investigated using Bayesian hierarchical modelling. Our main finding was that RMSSD of 101 middle-aged males was positively associated with brain glucose metabolism in occipital lobe, parietal lobe, precuneus, and cuneus. A negative association was observed in the cerebellum, thalamus, and parahippocampus. These findings suggest that brain regions associated with psychiatric disorders and cognitive and affective functions are associated with parasympathetic activity, as measured by the RMSSD. This study provides new insights into the mechanisms regarding autonomic nervous system.

We quantified, using a new method, the contribution of heart rate (HR), stroke volume (SV) and total peripheral resistance (TPR) to the increase in mean arterial pressure (MAP), expressed as % of baseline during a 3-min static handgrip (HG) performed at 30% of maximum voluntary contraction by 11 subjects. Arterial pressure was measured noninvasively with Finapres Nova, SV with Doppler imaging. The increase in MAP was greater at the end of HG than at the end of the first minute of HG, the maximum individual increases in MAP ranged from 0% to 33%; the HR contribution was mostly positive, the SV contribution was mostly negative. The magnitude of the HR contribution was similar at the beginning and end of the HG both in subjects who experienced high and low MAP increases; a similar observation applies to the SV contribution. Only the TPR contribution was significantly correlated with the individual MAP increase. Assuming that the individual level of MAP is set during HG, the contribution of TPR by taking positive or negative values plays a main role as an adjustment factor that brings MAP to set level; compensating for insufficient or excessive contributions from HR and SV. Our results question the use of changes in MAP or TPR as an indicator of sympathetic reactivity; the increase in MAP is determined by the individual change in set level induced by HG, whereas the magnitude of the change in sympathetic activity is such as needed to achieve the desired increase in MAP.

A nonexercise prediction equation for cardiovascular disease (CVD) patients was developed using the Fitness Registry and the Importance of Exercise National Database (FRIEND), which reported improved accuracy in predicting peak oxygen uptake (VO₂) in CVD patients. However, racial/ethnic differences have been observed in the predicted peak VO₂. The purpose of this study was to evaluate the usefulness of the FRIEND CVD cohort equation in predicting peak VO₂ in Japanese cardiac rehabilitation patients. We retrospectively enroled 362 Japanese cardiac rehabilitation patients (phase II–III) who underwent cardiopulmonary exercise testing. We compared the measured peak VO₂ with the predicted peak VO₂ calculated from three prediction equations: the FRIEND CVD cohort equation, the FRIEND healthy cohort equation, and the Japanese healthy population equation. The measured peak VO₂ was 20.9 ± 5.2 mL/kg/min. Bland-Altman analysis revealed that the FRIEND CVD cohort equation had the lowest bias (−2.32 mL/kg/min), while the FRIEND healthy cohort (11.11 mL/kg/min) and the Japanese healthy population equations (3.14 mL/kg/min) showed higher biases. The FRIEND CVD cohort equation had the highest correlation coefficient (r = 0.61), coefficient of determination (R² = 0.34), and intraclass correlation coefficient (ICC = 0.47) with measured peak VO₂ compared to other equations. In Japanese cardiac rehabilitation patients, the FRIEND CVD cohort equation provided more accurate predictions of peak VO₂ compared to the equation developed for the Japanese healthy population. However, prediction accuracy remained moderate or lower, indicating limitations for clinical use and the need for CVD-specific equations across different racial and ethnic groups.