Long-Term follow-up of the circadian rhythm of heart rate and heart rate variability in healthy elderly patients

The association between continuous ambulatory heart rate, heart rate variability, and 24-h rhythms of heart rate with familial longevity and aging

Aging is associated with changes in heart rate (HR), heart rate variability (HRV), and 24-h rhythms in HR. Longevity has been linked to lower resting HR, while a higher resting HR and a decreased HRV were linked to cardiovascular events and increased mortality risk. HR and HRV are often investigated during a short electrocardiogram (ECG) measurement at a hospital. In this study, we aim to investigate the relationship between HR parameters with familial longevity and chronological age derived from continuous ambulatory ECG measurements collected over a period of 24 to 90 hours. We included 73 middle-aged participants (mean (SD) age: 67.0 (6.16) years), comprising 37 offspring of long-lived families, 36 of their partners, and 35 young participants (22.8 (3.96) years). We found no association with familial longevity, but middle-aged participants had lower 24-h HR (average and maximum HR, not minimum HR), lower amplitudes, and earlier trough and peak times than young participants. Associations in HR with chronological age could be caused by the aging process or by differences in environmental factors. Interestingly, middle-aged participants had a less optimal HRV during long-term recordings in both the sleep and awake periods, which might indicate that their heart is less adaptable than that of young participants. This could be a first indication of deteriorated cardiovascular health in middle-aged individuals.

Non-Contact Measurement of Heart Rate Variability in Frail Geriatric Patients: Response to Early Geriatric Rehabilitation and Comparison with Healthy Old Community-Dwelling Individuals - A Pilot Study

INTRODUCTION

Frailty is a central geriatric syndrome characterized by a state of increased physiological vulnerability. As the key components of frailty are difficult to capture in their entirety, easily measurable and reliable surrogate parameters are desirable. Since frailty influences heart rate variability (HRV), HRV may be such a surrogate parameter. HRV is typically acquired by an ECG, which, however, may not be tolerated by all patients; in some, it may even trigger delirium. Therefore, we sought to measure HRV in a non-contact and unobtrusive way through photoplethysmography imaging (PPGI). Using our previously presented HRV estimation algorithm for PPGI, we investigated whether PPGI could reveal (1) HRV differences between frail and non-frail individuals and (2) the influences of early geriatric rehabilitation on HRV.

METHODS

The study involved 10 frail geriatric inpatients undergoing early geriatric rehabilitation and 10 healthy community-dwelling older adults. All participants underwent a comprehensive geriatric assessment. HRV measurements using a PPGI system and a reference ECG were made at the beginning and the end of the rehabilitation. HRV in terms of LF/HF ratio was analysed for both intra-individual changes during the geriatric rehabilitation and differences between frail geriatric patients and healthy community-dwelling individuals.

RESULTS

Across all geriatric patients, the median LF/HF ratio obtained with PPGI was found to be reduced by 0.178 (24.8%) during early geriatric rehabilitation. The assessment at the end of the rehabilitation revealed a simultaneous improvement of the functional state. Moreover, frail geriatric patients had a higher LF/HF ratio than their community-dwelling counterparts. Both observations in PPGI-based HRV were confirmed by the reference. The capability of PPGI to track intra-individual HRV changes was also analysed; a Spearman correlation of ρ = 1.0 between PPGI-based HRV and reference was achieved for 58.8% of the participants.

CONCLUSION

Early geriatric rehabilitation improves the functional state, which is associated with an increased HRV. PPGI is capable of detecting HRV changes/trends in that age group. While the tracking of intra-individual HRV changes is also possible, its reliability needs improvement. Nevertheless, the capabilities demonstrated in our study and the non-contact measurement principle of PPGI emphasize its potential for application in geriatric medicine.

Circadian rhythm of airways caliber and its autonomic modulation

The autonomic nervous system (ANS) is one of the effector pathways for circadian variation of many physiological parameters. Autonomic tone and airways caliber have been reported to exhibit circadian variation in separate studies. A simultaneous investigation of heart rate variability (HRV) and airway caliber might ascertain how airway caliber is modulated by autonomic tone. This study was planned to identify the variations in airway caliber and autonomic function tone during a 24-hour span. A total of 56 healthy male subjects with almost similar daily routines were studied. Time domain, frequency domain and nonlinear analysis of R-R interval from 5 min electrocardiogram (ECG) was done seven times during the daytime wake span at 3-hour intervals starting at 05:00 h in the morning until 23:00 h in the night. Simultaneously peak expiratory flow rate (PEFR) was determined using a mini Wright's peak flow meter. Rhythmometric analysis was done for PEFR and HRV parameters. Significant circadian variation in low frequency (LF) and high frequency (HF) variance was identified in this group of healthy subjects. The circadian rhythm of LF variance was characterized by a gradual increase and corresponding reciprocal change in HF variance from morning until night. The LF/HF ratio and SD2/SD1 ratio reflecting sympatho-vagal balance showed low to high values from morning to evening. The acrophase of the PEFR temporal pattern is similar to that of LF power and almost opposite in phase to that of HF power. PEFR is positively correlated with LF power. The circadian rhythm of airway caliber co-varies with cardiac autonomic tone. It appears that the temporal pattern of cardiac autonomic tone precedes in time that of airways caliber, thereby suggesting the latter operates under the modulatory effect of the 24-hour pattern in sympatho-vagal balance.

Primary and secondary haemostasis changes related to aging

Life expectancy has increased in many countries as a result the world's population is aging. The projections indicate that the proportion of the elderly in a few decades will increase significantly. Aging carries with it a series of physiological changes; one of them is an imbalance in the hemostatic system. Thus the levels or activity of various proteins involved, such as most coagulation factors, natural anticoagulants and the fibrinolytic system are altered so that the hemostatic balance leans toward thrombosis. Also, platelet activity suggests a state of abnormal activation (P-selectin, beta thromboglobulin and platelet factor). In this review we will systematically examine the alterations in the hemostatic components that occur during aging. Therefore, understanding these hemostatic changes could contribute to developing strategies for the proper management of health in old age.

Avaliação do grau de ansiedade dos pacientes antes de cirurgias orais menores

INTRODUÇÃO: Medo e ansiedade são comuns a pacientes que requerem tratamento odontológico e, em se tratando de procedimentos cirúrgicos, a ansiedade pode tornar-se um fator complicador, a partir do momento em que a alteração dos sinais vitais do paciente pode gerar situações de emergência. OBJETIVO: Avaliar o grau de ansiedade pré-operatória dos pacientes submetidos a cirurgias orais, identificando qual procedimento cirúrgico causa mais ansiedade nos pacientes e qual o momento cirúrgico causador de maior ansiedade. MATERIAL E MÉTODO: Foram selecionados 200 pacientes que iriam se submeter a cirurgias bucais nos ambulatórios do Departamento de Odontologia da Universidade Federal de Sergipe. No dia da cirurgia, os pacientes respondiam à escala EAD, tendo sido avaliadas a frequência cardíaca (FC) e a pressão arterial sanguínea (PA), considerados dados basais dos parâmetros físicos empregados para a avaliação da ansiedade pré-operatória. RESULTADO: Não houve diferenças estatisticamente significantes (Kruskal-Wallis, p=0,6933) entre os tratamentos em relação à ansiedade. A correlação de Spearman (rS) entre os valores obtidos para a ansiedade e os valores de pressão arterial e frequência cardíaca revelou-se fraca (rS<0,2), embora significativa (p<0,05) entre os resultados. A anestesia foi o momento que produziu maior ansiedade (Kruskal-Wallis, p<0,05), em relação aos demais momentos. CONCLUSÃO: A ansiedade teve influência no aumento da frequência cardíaca e da pressão arterial sistólica, tornando-se importante o seu controle pelo cirurgião-dentista para evitar complicações no decorrer da cirurgia.

Does the aging process significantly modify the Mean Heart Rate?

Background

The Mean Heart Rate (MHR) tends to decrease with age. When adjusted for gender and diseases, the magnitude of this effect is unclear.

Objective

To analyze the MHR in a stratified sample of active and functionally independent individuals.

Methods

A total of 1,172 patients aged ≥ 40 years underwent Holter monitoring and were stratified by age group: 1 = 40-49, 2 = 50-59, 3 = 60-69, 4 = 70-79, 5 = ≥ 80 years. The MHR was evaluated according to age and gender, adjusted for Hypertension (SAH), dyslipidemia and non-insulin dependent diabetes mellitus (NIDDM). Several models of ANOVA, correlation and linear regression were employed. A two-tailed p value <0.05 was considered significant (95% CI).

Results

The MHR tended to decrease with the age range: 1 = 77.20 ± 7.10; 2 = 76.66 ± 7.07; 3 = 74.02 ± 7.46; 4 = 72.93 ± 7.35; 5 = 73.41 ± 7.98 (p < 0.001). Women showed a correlation with higher MHR (p <0.001). In the ANOVA and regression models, age and gender were predictors (p < 0.001). However, R² and ETA² < 0.10, as well as discrete standardized beta coefficients indicated reduced effect. Dyslipidemia, hypertension and DM did not influence the findings.

Conclusion

The MHR decreased with age. Women had higher values of MHR, regardless of the age group. Correlations between MHR and age or gender, albeit significant, showed the effect magnitude had little statistical relevance. The prevalence of SAH, dyslipidemia and diabetes mellitus did not influence the results.

Activity of autonomic nervous system is related to body weight in pre-menopausal, but not in post-menopausal women

This study analyzed vegetative modulation, expressed as heart rate variability (HRV) power spectral analysis, in lean and obese women at pre-menopausal or post-menopausal age to reveal possible differences in menopause-related autonomic activity in lean and obese subjects. Sedentary women (n = 40) were divided in four groups: pre-menopausal lean and obese women, post-menopausal lean and obese subjects. The HRV-power spectrum was evaluated on a 5-min long ECG recording. The absolute values of the spectrum were summed in the following frequencies: a low-frequency (0.04-0.15 Hz; LF) and high-frequency (0.15-0.40; HF) range. LF and HF were values used to estimate the sympathetic and parasympathetic activity. LF and HF values of pre-menopausal obese women are lower than values of lean women. The menopause induced a same decrease in LF and HF values in lean and obese subjects, so that no difference was found in post-menopausal groups. This experiment indicates that modifications of autonomic modulation can be included among factors related to obesity in pre-menopausal, but not post-menopausal women.

Influence of age on heart rate variability during therapeutic hypothermia in a rat model

OBJECTIVES

To evaluate the effect of age on heart rate variability (HRV) in a rat model of therapeutic hypothermia.

METHODS

Thirty-six male Sprague-Dawley rats (18 were 2 months old and 18 were 18 months old) were randomized into one of three groups: normothermia (37°C), mild hypothermia (34°C), and moderate hypothermia (31°C). An electrocardiogram (ECG) was recorded at baseline and continuously for 1h once the target core body temperature was reached. Various heart rate variability measurements were calculated.

RESULTS

Significant effects of age were observed in respect to the ratio of standard deviation of all normal to normal R-R [NN] intervals (SDNN)/standard deviation of the differences between adjacent NN intervals (SD of delta NN) (P=0.037), low frequency (LF) power, normalized units (nu, %) (P<0.001), and the ratio of LF and high frequency (HF) (P<0.001). Significant effects of temperature were found in LF power and a significant body-temperature interaction was found in HF power. HF power was significantly lower in the young rats at mild and moderate hypothermic conditions. For the LF/HF, the ratio was significantly lower in the young animals compared to the older animals at normal body temperatures and during mild hypothermia. LF/HF increased significantly at both 34°C and 31°C in the young rats compared to the young rats at 37°C. In contrast, LF/HF was significantly lower in the older group of rats at 34°C and 31°C compared to the older group of rats maintained under normothermic conditions.

CONCLUSIONS

This study noted that autonomic regulation determined via HRV, primarily the ratio of LF to HF, was different between different age groups. Additional studies on this topic are needed to achieve a more detailed understanding of therapeutic hypothermia.

Analysis of heart rate variability as an index of noncardiac surgical stress

Measurement of heart rate variability (HRV) is useful in assessing the function of the autonomic nervous system and in staging of clinical diseases. The purpose of this study is to assess a feasibility of HRV for evaluating surgical stress during the noncardiac perioperative period. Standard deviation of normal-to-normal RR intervals (SDNN) and HRV triangular index derived from 24-h Holter ECC were measured in 24 patients undergoing digestive surgery. Holter ECG was performed at 1 day before operation, the first day (postoperative day 1: POD1), and the 7th day (POD7) after operation. Indices of HRV were compared with factors influencing surgical stress, such as duration of the operation and amount of blood loss during the operation, and postoperative complications. The SDNN and HRV triangular index decreased significantly on POD1 and recovered on POD7 (P < 0.05). Heart rate variability indices correlated significantly to duration and blood loss of operation (both P < 0.05). In 7 patients with postoperative complications, HRV indices were statistically lower than those in patients without complications on POD1 (P < 0.05). Our results indicate that HRV may provide useful information with respect to surgical stress.

Longitudinal Age-Related Changes in 24-Hour Total Heart Beats and Premature Beats and Their Relationship in Healthy Elderly Subjects

The aim of this study was to conduct a longitudinal follow-up on age-related changes in 24-hour total heart beats (THBs) and total premature beats and their correlations in healthy elderly subjects. In 15 healthy elderly subjects (mean age, 70.0 +/- 4.1, age range at 1st recording, 64 to 80 years, 10 females, 5 males), we conducted Holter monitoring twice at an interval of 15 years and analysed age-related changes in THBs, atrial premature beats (APBs), and ventricular premature beats (VPBs), as well as their correlations. The results indicated that THBs, APBs, and VPBs all significantly increased with age in the healthy elderly subjects at a mean age of 70.0 +/- 4.1 (THB: 91074.1 +/- 11515.3 versus 99457.5 +/- 12131.0; P = 0.0004, APB:119.2 +/- 97.8 versus 884.4 +/- 1193.8; P = 0.0008, VPB: 15.2 +/- 53.6 versus 140.7 +/- 228.9; P = 0.0328). Moreover, we divided the subjects into increase and nonincrease groups based on the age-related changes in APB and VPB for 15 years ([n]; Inc-APB: Noninc-APB = 6 : 9, Inc-VPB: Noninc-VPB = 5 : 10). In the increase groups, premature beats tended to increase in proportion to changes in THBs with age (APB: Y = 207.488 + 0.136 X, r = 0.848, P = 0.0303; VPB: Y = -27.594 + 0.028 X, r = 0.727, P = 0.1921). In conclusion, this 15-year follow-up of Holter recordings in healthy elderly subjects revealed that THBs, APBs, and VPBs increased with age, and that the increases in premature beats, especially APBs, were in proportion to those in THBs.