Characterisation of cardiac autonomic function in multiple sclerosis based on spontaneous changes of heart rate and blood pressure

Objective: Seasonal blood pressure (BP) changes has been described in clinic BP. Few studies have examined the seasonal variation in BP and BP variability, assessed by 24-hour ambulatory blood pressure monitoring (ABPM) and it remains uncertain whether the seasonal trend differs between young and elderly hypertensive patients. Design and Method: A total of 1028 untreated essential hypertensive patients (mean age 52 ± 14 years) who underwent 24-hour ABPM between January 2009 and April 2013 were enrolled. Patients were divided into young (age ≤ 70 years, n = 927) and elderly (age > 70 years, n = 101) groups. Results: Compared to elderly group, young age group had higher clinic, 24-hour, daytime and night-time diastolic BP (DBP), higher clinic, 24-hour and daytime heart rate (HR), higher 24-hour and daytime HR variability (HRV), lower night-time systolic BP (SBP) and daytime SBP variability. In young age group, significant seasonal variation of clinic DBP and daytime SBP variability with a peak in autumn, and nighttime DBP and HR with a peak in spring and the increased prevalence of non-dippers in summer were observed. On the other hand, elderly group demonstrated seasonal variation of clinic, 24-hour, daytime and nighttime HR with a peak in autumn, daytime DBP with a peak in winter and night-time SBP variability with a peak in summer. Conclusions: There was an apparent seasonal variation of DBP, HR and SBP variability in both young and elderly hypertensive patients. However, elderly patients showed more pronounced seasonal change in HR compared to younger patients.

Background: The effects of empagliflozin in addition to standard care, on day-to-day variability of self-measured home blood pressure (BP) and heart rate (HR) at home in patients with type 2 diabetes (T2DM) at high cardiovascular risk are not known. Method: We followed twenty-three consecutive T2DM patients (mean age: 69 years old, 12 men) to add 10 mg of empagliflozin once daily for three months. Home BP and HR were measured once every morning at home, using an oscillometric device. The variability of BP and HR were defined as the standard deviations (SD) of measurements which were performed on seven consecutive days. Results: For home blood pressure, empagliflozin significantly reduced systolic blood pressure (SBP) from 130±11 mmHg at baseline to 126±11 mmHg at the first week(1W) of the administration (P<0.05). SBP achieved the target home BP goal (125±11 mmHg) at the second week(2W) and was maintained during the study (P<0.01). As regards day-to-day variability of SBP, SD decreased from 7.3±3.5 mmHg at baseline to 6.7±2.5 mmHg at 1W (4W: 6.4±2.8 mmHg, 8W: 5.2±2.3 mmHg, P<0.05). In diastolic blood pressure (DBP), there was a significant reduction of SD compared with that at baseline (4.9±1.6 mmHg at baseline, 4W: 4.3±1.6 mmHg, 8W: 3.9±1.8 mmHg, 12W: 4.4±1.6 mmHg, P<0.05); however, there was no change of DPB (71±10 mmHg at baseline, 12W: 71±8 mmHg). Similarly, there was a decreasing trend in SD of HR (3.9±1.0 beats per minute (bpm) at baseline, 4W: 3.3±1.3 bpm, 12W: 3.1±1.3 bpm, P<0.1), although there was no significant change in HR (62±13 bpm at baseline, 12W: 61 ± 12 bpm). Conclusion: Empagliflozin tended to reduce the day-to-day variability of self-measured morning home BP and HR.

Ambulatory blood pressure pattern in elderly athletes.

Heart rate (HR) variability and arterial blood pressure (BP) variability were analysed as functions of foetal breathing movements (FBMs) by means of power spectral analysis in seven foetal lambs during the third trimester of gestation. No evidence of FBM-related changes, either in mean HR, mean systolic or diastolic arterial pressures, were found. Mean arterial pulse pressure, HR variability, and BP variability increased during FBMs. The increase in BP variability occurred at frequencies higher than 0.35 Hz, i.e. those of FBMs. The increase in HR variability occurred at 0.07-1.0 Hz, i.e. at every frequency band except the lowest one. Thus, the increase in HR variability was not frequency-specifically related to FBMs. During FBMs the periodic variability of HR at frequencies > 0.35 Hz was only 10% of total HR variability. We suggest that the FBM-related changes of BP variability may be mediated by direct peripheral, hydraulic mechanisms. HR changes involve autonomic control systems: the vagal component of baroreflex seems to be relatively insensitive, whereas the very slow vasomotor component of HR variability is dominant.

Day‐to‐day blood pressure variability and severity of COVID‐19: Is sympathetic overdrive a potential link?

Objective To investigate the association between visit-to-visit variability in blood pressure and cognitive function in old age (>70 years). Design Prospective cohort study.Setting PROSPER (PROspective Study of Pravastatin in the...

Contribution of the renin-angiotensin and kallikrein-kinin systems to short-term variability of blood pressure in two-kidney, one-clip hypertensive rats

Evidence suggests a relationship between short-term blood pressure (BP) variability and cardiovascular target-organ damage. Although a blunted nocturnal decrease in BP and reduced heart rate variability have been shown to be associated with cardiovascular morbidity in diabetic patients, little information is available on short-term BP variability. In this study, short-term BP variability was assessed in 36 subjects with type 2 diabetes and overt nephropathy who underwent ambulatory BP monitoring, and the factors that correlated with short-term BP variability were examined. The incidence of coronary artery disease (CAD) was significantly greater in the patients with increased 24-h systolic BP variability (67% versus 11%; p < 0.0005), while that of cerebrovascular disease was not significantly affected (61% versus 50%). Multiple stepwise regression analysis revealed that serum cholesterol (cholesterol) and plasma norepinephrine (p-NE) were significant and independent contributors to nighttime systolic BP variability (partial R2 = 0.490, p < 0.001; partial R2 = 0.470, p < 0.001) and demonstrated that body mass index and p-NE were primary determinants of nighttime diastolic BP variability (partial R2 = 0.539, p < 0.0005; partial R2 = 0.304, p < 0.05). Diabetic nephropathy patients with CAD had significantly increased daytime systolic (17.8 mmHg versus 13.1 mmHg, p < 0.0005), nighttime systolic (17.4 mmHg versus 10.5 mmHg, p < 0.0001), and nighttime diastolic (10.4 mmHg versus 7.2 mmHg, p < 0.05) BP variability. Furthermore, logistic regression analysis demonstrated that nighttime systolic BP variability was an independent risk factor for CAD (odds ratio 3.13 [95% CI 1.02–9.61]; p < 0.05). The increase in nighttime BP variability is associated with a proportional sympathetic activation in diabetic nephropathy. Elevated short-term BP variability combined with relative sympathetic prevalence during the night might represent an important risk factor for cardiovascular events in the diabetic population.

Objective: Renal blood flow and function are largely dependent on systemic blood pressure (BP) and heart rate (HR). Though high and low BP levels have been associated to renal dysfunction, the effect of HR levels, BP and HR variability on renal function are less well studied. Furthermore, smoking seems to influence intrarenal hemodynamics and nephropathy risk. This study sought to determine the value of 24-hour BP and HR variability and their interplay as indicators of renal function, stratified by smoking. Design and method: The study comprised all non-diabetic, never-treated hypertensives referred to our hypertensive units from 1985 to 2014 (n = 9400, 53.2 ± 13.5 years, 54.9% men). Ambulatory BP and HR recording was performed. The 24-hour systolic BP (SBP) and HR variability was estimated via the coefficient of variation (CV = standard deviationx100/mean value). The interplay of 24-hour SBP and HR variability was estimated with the CV_SBP-to-CV_HR ratio (CVR). Renal function was estimated via the creatinine clearance (CrCl) in 24-hour urine, the estimated glomerular filtration rate (eGFR) and the albumin-to-creatinine ratio (ACR). Partial correlations controlled for age, sex and smoking were performed. Results: The mean CV_SBP, CV_HR and CVR were 10.8%, 15.2% and 0.75, respectively. CV_SBP was weakly negatively correlated to CrCl and eGFR and more strongly positively correlated to ACR (r = -0.019, -0.006 and 0.061 with p = 0.060, 0.566 and <0.001, respectively). CV_HR was a much better indicator with significant correlations, positive to CrCl and eGFR and negative to ACR (r = 0.181, 0.126 and -0.303, all p < 0.001). CVR was an equally good indicator with significant correlations, negative to CrCl and eGFR and positive to ACR (r = -0.167, -0.112 and 0.330, all p < 0.001). The correlations were even better in smokers for CV_HR and CVR (r = 0.212, 0.153 and -0.331 for CV_HR, -0.182, -0.113 and 0.352 for CVR, all p < 0.001). Conclusions: CV_HR and CVR are better indicators of renal function compared to CV_SBP. Their value is even better in smokers. The effect of CV_HR and CV_SBP on renal function is inverse to each other. ACR is better related to hemodynamic indices’ variability than CrCl and eGFR.

Heart rate and blood pressure variabilities are increased in pregnancy-induced hypertension

The aim of the study was to compare changes in blood pressure (BP) and heart rate (HR) variability, catecholamine and neuropeptide Y (NPY) plasma levels induced by passive head-up tilt in normal and sino-aortic denervated (SAD) chloralose-anaesthetized dogs. In controls, 80 degrees head-up tilt test failed to change BP and increased HR. Plasma noradrenaline and NPY levels (but not adrenaline) significantly rose. In SAD dogs, head-up tilt test induced a marked and reproducible decrease in BP without any change in HR or noradrenaline and NPY plasma levels. In SAD dogs, spectral analysis in supine position was characterized by reduced variability in the high frequency (HF) band of the HR spectrum without changes in low frequency (LF) bands of both HR and systolic blood pressure (SBP). Head-up tilt test increased the LF component of SBP variability and decreased the HF component of HR variability in controls but failed to modify HR and BP variabilities in SAD dogs. In conclusion, sino-aortic denervation in dogs elicits a reproducible postural fall in BP with impaired adaptation of sympathetic nervous system activity. This model may be of value in evaluating the pharmacological effects of drugs for the management of orthostatic hypotension.

Dissociation between ACE activity and autonomic response to ACE inhibition in patients with heart failure

To investigate the association between cardiovascular mortality and short-term variabilities in blood pressure and heart rate, we performed a long-term prospective study of ambulatory blood pressure monitoring in Ohasama, Japan, starting in 1987. We obtained ambulatory blood pressure and heart rate in 1542 subjects >/=40 years of age. Blood pressure and heart rate variabilities were estimated as a standard deviation measured every 30 minutes by ambulatory monitoring. There were 67 cardiovascular deaths during the follow-up period (mean=8.5 years). The Cox proportional hazards model, adjusted for possible confounding factors, demonstrated a significant increase in cardiovascular mortality, with an increase in daytime systolic ambulatory blood pressure variability. A similar trend was observed in daytime diastolic and nighttime ambulatory blood pressures. Cardiovascular mortality rate increased linearly, with a decrease in daytime heart rate variability. Subjects in whom the daytime systolic ambulatory blood pressure variability was larger than third quintile and the daytime heart rate variability was lower than the mean-SD were at extremely high risk of cardiovascular mortality. The blood pressure and heart rate variabilities obtained every 30 minutes by ambulatory blood pressure monitoring were independent predictors for cardiovascular mortality in the general population.

Even at rest, blood pressure and heart fluctuate continuously around their mean values. Considerable interest has recently focused on the assessment of spontaneous in fluctuations in heart rate and blood pressure, i.e., heart rate and blood pressure variability, using time or frequency domain indexes. Heart rate variability has been extensively studied in cardiovascular disease and has emerged as a valuable parameter for detecting abnormalities in autonomic cardiovascular control, evaluating the prognosis and assessing the impact of drug therapy on the autonomic nervous system in patients with myocardial infarction, congestive heart failure or a heart transplant. In contrast, until the recent development of noninvasive methods for continuous blood pressure recording, blood pressure variability received little attention, and this parameter remains to be evaluated in cardiovascular disease.

sponsorship: The European Union (HEALTH-F7-2011-278249 EU-MASCARA, HEALTH-F7-305507 HOMAGE and the European Research Council Advanced Researcher Grant 294713 EPLORE) and the Fonds voor Wetenschappelijk Onderzoek Vlaanderen, Ministry of the Flemish Community, Brussels, Belgium (G.0881.13 and G.0880.13) currently support the Studies Coordinating Centre (Leuven, Belgium). (European Union|HEALTH-F7-2011-278249 EU-MASCARA, European Union|HEALTH-F7-305507 HOMAGE, European Union (European Research Council)|294713 EPLORE, Fonds voor Wetenschappelijk Onderzoek Vlaanderen, Ministry of the Flemish Community, Brussels, Belgium|G.0881.13, Fonds voor Wetenschappelijk Onderzoek Vlaanderen, Ministry of the Flemish Community, Brussels, Belgium|G.0880.13)