RESUMO
Stress is recognized as a significant trigger and exacerbator of various medical conditions, particularly in the field of cardiovascular disease (CVD). Given that heart rate variability (HRV) offers insight into the functioning of the autonomic nervous system and has been identified as a predictive factor for increased cardiovascular mortality, exploring the correlation between stress and HRV is pertinent. We systematically reviewed trials where researchers investigated the effects of stress-reducing interventions on biomarkers and time-domain/frequency-domain parameters of HRV in CVD. Eligible studies underwent meta-analysis utilizing a random-effects model. The meta-analysis showed overall beneficial effects of stress-reducing interventions on HRV for the standard deviation of Normal-to-Normal intervals (SDNN) in short-term and 24 h assessments, as well as for the low-frequency power (LF) in short-term assessment. Overall effect sizes were notably high and showed significant p-values (short-term SDNN: MD = 6.43, p = 0.01; 24 h SDNN: MD = 10.92, p = 0.004; short-term LF: MD = 160.11, p < 0.001). Our findings highlight the significant impact of stress-reducing interventions in modulating HRV by influencing short-term SDNN and LF parameters, as well as the 24 h assessment of SDNN. These results emphasize the importance of stress-reducing measures in lowering the risk of further progression in CVD and improving patient outcomes.
RESUMO
BACKGROUND: Cardiovascular diseases (CVD) are the leading causes of morbidity and mortality. Heart rate variability (HRV) represents the modulatory capacity of the autonomous nervous system and influences mortality. By surveying this meta-analysis, we investigated the impact of physical activity on HRV. METHODS: Databases, online journal libraries and clinical trial registries were searched for publications of randomized controlled and non-randomized controlled trials concerning adults with coronary artery disease (CAD)/ischemic heart disease (IHD), congestive heart failure (CHF), peripheral arterial disease (PAD) or after acute coronary syndrome (ACS) joining an intervention group with physical activity or a control group with usual care or no intervention. Extracted time-domain and frequency-domain parameter of HRV were analyzed in a meta-analysis using a random effect model. Subgroup analyses concerning intervention type, study design and type of heart disease and sensitivity analysis were performed. RESULTS: Significant results were obtained for RR-Interval (p = 0.05) and standard deviation of Normal-to-Normal intervals (SDNN) (p = 0.01) for short-term assessment and for the ratio of low-frequency power (LF) to high-frequency power (HF) (p = 0.05) for 24-hour assessment. Subgroup analyses also resulted significant: root-mean-square difference of successive normal R-R intervals (RMSSD) (p = 0.01), SDNN (p = 0.02) and HF (p < 0.01) concerning CHF. CONCLUSION: We were able to demonstrate the positive impact of physical activity on HRV, especially in patients with CHF. Cardiac rehabilitation exercise programs need to be individualized to identify the most beneficial method of training for improving the prognosis of patients with CVD.
Assuntos
Exercício Físico , Frequência Cardíaca , Humanos , Frequência Cardíaca/fisiologia , Exercício Físico/fisiologia , Doenças Cardiovasculares/fisiopatologiaRESUMO
PURPOSE: To evaluate the diagnostic power for glaucoma detection using circumpapillary retinal nerve fiber layer (cRNFL) thickness in 3 diameter sizes from the center of the optic nerve head (ONH) by spectral domain optical coherence tomography. PATIENTS AND METHODS: In this cross-sectional study, case-control, 437 eyes diagnosed with glaucoma and 183 eyes of healthy controls underwent spectral domain optical coherence tomography of the ONH, visual field testing, and a clinical examination. cRNFL was measured by circular scans in 3.5 (C1), 4.1 (C2), and 4.7 mm (C3) distance from the center of the ONH. Receiver-operator characteristic analysis was used to assess diagnostic power to detect glaucoma; furthermore, patient-specific maximum localized damage was analyzed. RESULTS: In C1, mean global cRNFL was 70.03±18.2 µm in glaucomatous eyes and 93.46±9.9 µm in controls. Respectively, cRNFL in C2 was 61.39±14.9 and 80.43±8.4 µm as well as 55.25±12.8 and 70.70±6.7 µm in C3. Using receiver-operator characteristic analysis, the area under the curve (AUC) for cRNFL was 0.855 in C1, 0.850 in C2, and 0.843 in C3. Mean AUCs in ONH sectors ranged from 0.699 to 0.846 and did not exceed AUC of the best scoring global parameter. CONCLUSIONS: Comparing 3.5, 4.1, and 4.7 mm diameters for cRNFL measurement, the inner circle at 3.5 mm distance showed the highest AUC to differentiate glaucoma from healthy controls. However, levels of diagnostic power from wider circular scans were not significantly different and were comparable. Moreover, sectorial cRNFL measurements were nonsuperior. The use of the ONH sector with the highest localized damage seems not to increase diagnostic power.