Predictive value of night-time heart rate for cardiovascular events in hypertension. The ABP-International study

Hemodynamic Predictors of Blood Pressure Responsiveness to Continuous Aerobic Training in Postmenopausal Hypertensive Women

Blood pressure (BP) responses to recommended aerobic training can vary widely between individuals. Although studies demonstrate the role of exercise training in regulating BP responsiveness, predictive models are still unknown. This study aimed to identify hemodynamic predictive markers for the diagnosis of BP responsiveness based on baseline characteristics and postexercise ambulatory blood pressure (ABP) before an aerobic training program in postmenopausal women. Sixty-five postmenopausal women with essential hypertension were randomly allocated into the continuous aerobic training (CAT, n = 51) and nonexercising control (CON, n = 14) groups. CAT group cycled at moderate intensity three times a week for 12 weeks. Individuals who failed to decrease systolic blood pressure (SBP) were classified as nonresponders (NRs; n = 34) based on typical error of measurement. Baseline anthropometric, metabolic, cardiovascular, hemodynamic variables, and postexercise ABP was measured to predict BP responsiveness. A logistic regression model based on Baseline SBP [odds ratio (OR) = 1.202; 95% confidence interval (CI) = 1.080-1.338], SBP Nighttime (OR = 0.889; 95% CI = 0.811-0.975), and heart rate (HR) Nighttime (OR = 1.127; 95% CI = 1.014-1.254) were able to diagnose responders and NR individuals to BP reduction in response to CAT with 92.6% accuracy (P < 0.001; Sensitivity = 94.1%; Specificity = 79.4%). The findings highlight the potential value of baseline clinical characteristics as Baseline SBP, SBP, and HR Nighttime as markers for diagnosing BP responsiveness to recommended CAT in hypertension postmenopausal women. Clinical Trial Registration number: RBR-3xnqxs8.

High blood pressure with elevated resting heart rate: a high risk "Sympathetic" clinical phenotype

Epidemiological studies have unequivocally shown that elevated heart rate values measured at rest have an adverse prognostic impact in the hypertensive patient, being associated with an increased risk of cardiovascular events and complications. In recent years new data have been collected on this issue, strengthening the clinical relevance of elevated heart rate as a specific hypertensive phenotype. The present paper will review old and new data on the prognostic importance of resting tachycardia in the hypertensive patient. It will also examine the role of the sympathetic nervous system in the development of this alteration as well as its therapeutic implications. The different approaches to dynamically assess heart rate values in the clinical setting will be finally discussed.

Nondipping blood pressure pattern predicts cardiovascular events and mortality in patients with atherosclerotic peripheral vascular disease

BACKGROUND

Patients with peripheral vascular disease (PVD) are often underdiagnosed and undertreated. Nocturnal nondipping blood pressure (BP) pattern, as diagnosed by ambulatory BP monitoring (ABPM), is associated with increased cardiovascular risk, but has not been studied in patients with PVD. We aimed to investigate if a nondipping BP pattern predicts cardiovascular events or all-cause death in outpatients with PVD.

METHODS

Consecutive outpatients with carotid or lower-extremity PVD were examined with 24-hour ABPM (n = 396). Nondipping was defined as a < 10% fall in systolic BP level during night-time. We used Cox regression models adjusting for potential confounders. We also evaluated the incremental prognostic value of dipping status in the COPART risk score. Our primary composite outcome was cardiovascular events or all-cause death.

RESULTS

In the cohort (mean age 70; 40% women), 137 events occurred during a 5.1-year median follow-up; incident rate of 7.35 events per 100 person-years. Nondipping was significantly associated with outcome (hazard ratio 1.55, 95% CI 1.07-2.26, p = 0.021) in a fully adjusted model. When adding nondipping to the risk markers in the COPART risk score, the model fit significantly improved (χ2 7.91, p < 0.005) and the C-statistic increased from 0.65 to 0.67.

CONCLUSION

In a cohort of outpatients with PVD, nondipping was an independent risk factor for future cardiovascular events or mortality and seemed to be a strong predictor in patients with carotid artery disease but not in lower-extremity PVD. Additional studies are needed to evaluate the clinical utility of ABPM for improved prevention in these high-risk patients. (ClinicalTrials.gov Identifier: NCT01452165).

Circadian Factors in Stroke: A Clinician's Perspective

Stroke remains one of the leading causes of mortality and long-term and permanent disability worldwide despite technological innovations and developments in pharmacotherapy. In the last few decades, the growing data have evidenced the role of the circadian system in brain vulnerability to damage, the development and evolution of stroke, and short-term and long-term recovery. On the other hand, the stroke itself can affect the circadian system via direct injury of specific brain structures involved in circadian regulation (i.e., hypothalamus, retinohypothalamic tracts, etc.) and impairment of endogenous regulatory mechanisms, metabolic derangement, and a neurogenic inflammatory response in acute stroke. Moreover, the disruption of circadian rhythms can occur or exacerbate as a result of exogenous factors related to hospitalization itself, the conditions in the intensive care unit and the ward (light, noise, etc.), medication (sedatives and hypnotics), and loss of external factors entraining the circadian rhythms. In the acute phase of stroke, patients demonstrate abnormal circadian variations in circadian biomarkers (melatonin, cortisol), core body temperature, and rest-activity patterns. The approaches aimed at the restoration of disrupted circadian patterns include pharmacological (melatonin supplementation) and non-medication (bright light therapy, shifting feeding schedules, etc.) interventions; however, their effects on short- and long-term recovery after stroke are not well understood.

Measure by measure: Resting heart rate across the 24-hour cycle

BACKGROUND

Photoplethysmography (PPG) sensors, typically found in wrist-worn devices, can continuously monitor heart rate (HR) in large populations in real-world settings. Resting heart rate (RHR) is an important biomarker of morbidities and mortality, but no universally accepted definition nor measurement criteria exist. In this study, we provide a working definition of RHR and describe a method for accurate measurement of this biomarker, recorded using PPG derived from wristband measurement across the 24-hour cycle.

METHODS

433 healthy subjects wore a wrist device that measured activity and HR for up to 3 months. HR during inactivity was recorded and the duration of inactivity needed for HR to stabilise was ascertained. We identified the lowest HR during each 24-hour cycle (true RHR) and examined the time of day or night this occurred. The variation of HR during inactivity through the 24-hour cycle was also assessed. The sample was also subdivided according to daily activity levels for subset analysis.

FINDINGS

Adequate data was obtained for 19,242 days and 18,520 nights. HR stabilised in most subjects after 4 minutes of inactivity. Mean (SD) RHR for the sample was 54.5 (8.0) bpm (day) and 50.5 (7.6) bpm (night). RHR values were highest in the least active group (lowest MET quartile). A circadian variation of HR during inactivity was confirmed, with the lowest values being between 0300 and 0700 hours for most subjects.

INTERPRETATION

RHR measured using a PPG-based wrist-worn device is significantly lower at night than in the day, and a circadian rhythm of HR during inactivity was confirmed. Since RHR is such an important health metric, clarity on the definition and measurement methodology used is important. For most subjects, a minimum rest time of 4 minutes provides a reliable measurement of HR during inactivity and true RHR in a 24-hour cycle is best measured between 0300 and 0700 hours. Funding: This study was funded by Google.

Nighttime hemodynamic phenotype. A novel risk factor for cardiovascular disease, especially heart failure: the practitioner-based nationwide JAMP study

BACKGROUND

Non-dipper and riser patterns of nocturnal blood pressure (BP) are risk factors for cardiovascular disease (CVD), including heart failure (HF). However, the risk associated with a disrupted nocturnal pattern of heart rate is not well known.

OBJECTIVES

To investigate whether the nighttime heart rate is a risk factor for HF, alongside nighttime BP phenotype.

METHODS

The practitioner-based, nationwide, prospective Japan Ambulatory Blood Pressure Monitoring Prospective (JAMP) study included patients with ≥ 1 CVD risk factor but without symptomatic CVD at baseline. All patients underwent 24-h ambulatory BP monitoring at baseline and were followed annually. Nocturnal heart rate dipping (%) was calculated as 100•[1 - nighttime/daytime heart rate].

RESULTS

During a mean 4.5 years' follow-up in 6,359 patients (mean age 68.6 years), there were 306 CVD events (119 stroke, 99 coronary artery disease, and 88 HF). A 10-beats/min increase in nighttime heart rate was significantly associated with a 36-47% increase in the risk of total CVD, stroke and HF events independently of office SBP and nighttime SBP (all p < 0.005). The CVD and HF risk associated with nocturnal heart rate dipping status was independent of office and 24-h systolic BP and nocturnal BP dipping status (p < 0.001). Performance of the final model for predicting HF including BP parameters was significantly improved by the addition of nocturnal heart rate dipping patterns (p = 0.038; C-statistic 0.852).

CONCLUSION

Nighttime non-dipper and riser patterns of heart rate were associated with CVD especially HF, independently and additively of nocturnal BP dipping status, indicating the importance of antihypertensive strategies targeting nighttime hemodynamics.

CLINICAL TRIAL REGISTRATION

URL: https://www.umin.ac.jp/ctr/ ; Unique identifier: UMIN000020377.

Cardiovascular outcomes in obstructive sleep apnoea and implications of clinical phenotyping on effect of CPAP treatment

BACKGROUND

There is a growing awareness of the heterogeneity of obstructive sleep apnoea (OSA). Clinical trials of CPAP treatment on cardiovascular protection have been mostly negative. We aimed to assess the association between polysomnographic parameters and incident major adverse cardiovascular events (MACEs), and to investigate if the CPAP effect could be better delineated among clinical subgroups.

METHODS

This sleep cohort study was conducted using a clinical database and territory-wide electronic health administration data in Hong Kong. Cox regressions were used to calculate HRs. Latent class analysis was used to cluster patients with OSA according to clinical and polysomnographic features.

RESULTS

Of 1860 eligible Chinese subjects who underwent polysomnography (2006-2013), 1544 (83%) had OSA. Over median follow-up of 8.3 years, 278 (14.9%) experienced MACEs. Apnoea-hypopnoea index (AHI) did not predict MACEs (HR: 0.95; 95% CI 0.76 to 1.17), whereas sleep time with oxygen saturation <90% (TST90) (HR: 1.41; 95% CI 1.10 to 1.81) was an independent predictor of MACEs, as were wake and nocturnal heart rate. In moderate-severe OSA (n=1108) who were indicated for CPAP treatment, regular CPAP was not associated with reduction of incident MACEs. Further cluster analysis identified a subgroup (n=333) who was younger, more obese, had more severe OSA (higher AHI and TST90) and more cardiovascular risks, in whom regular CPAP was associated with a lower risk of MACEs (HR:0.49, 95% CI 0.25 to 0.95).

CONCLUSIONS

OSA-related TST90 and mean heart rate, but not AHI, were robust predictors of MACEs. A clinical phenotype subgroup who demonstrated beneficial effect of CPAP treatment was identified.

A personal history of research on hypertension From an encounter with hypertension to the development of hypertension practice based on out-of-clinic blood pressure measurements

In the 1970s, many people had severe hypertension and related cardiovascular and cerebrovascular diseases; however, antihypertensive treatments were not available at the time. The author encountered such conditions during the initial exposure to medicine. The author subsequently entered the field of hypertension medicine to prevent such conditions and engaged in hypertension research for more than 50 years. The author's central interest was the physiological and clinical aspects of blood pressure (BP) variability. Out-of-clinic BP measurements were the focus of clinical research. It was anticipated that self-measurement of BP at home (HBP) would improve medical practice surrounding hypertension. To establish evidence-based hypertension medicine, the Ohasama study (an epidemiology based on HBP) was conducted. The study provided firm evidence of the clinical significance of HBP and diagnostic criteria for hypertension and normotension. To establish target HBP levels for antihypertensive therapy, the Hypertension Objective treatment based on Measurement by Electrical Devices of Blood Pressure (HOMED-BP) study (a prospective intervention study) was also conducted. Application of HBP measurements expanded to obstetric, clinical pharmacology, pathophysiology, and genetic studies. During these studies, crucial information on the clinical significance of BP variability (such as circadian and day-by-day variation of BP, nocturnal BP, white-coat hypertension, and masked hypertension) was established. Finally, the author described the priority of HBP over clinic-measured BP for the diagnosis of hypertension in the 2014 Japanese Society of Hypertension Guidelines. In this article, the author's history of hypertension research, from the first encounter with hypertension to the construction of guidelines on hypertension, is reviewed.

Stress Management Intervention for Leaders Increases Nighttime SDANN: Results from a Randomized Controlled Trial

Stress management interventions aim to reduce the disease risk that is heightened by work stress. Possible pathways of risk reduction include improvements in the autonomous nervous system, which is indexed by the measurement of heart rate variability (HRV). A randomized controlled trial on improving stress management skills at work was conducted to investigate the effects of intervention on HRV. A total of 174 lower management employees were randomized into either the waiting list control group (CG) or the intervention group (IG) receiving a 2-day stress management training program and another half-day booster after four and six months. In the trial, 24 h HRV was measured at baseline and after 12 months. Heart rate (HR), root mean square of successive differences (RMSSD), standard deviation of normal-to-normal intervals (SDNN), and standard deviation of the average of normal-to-normal intervals (SDANN) were calculated for 24 h and nighttime periods. Age-adjusted multilevel mixed effects linear regressions with unstructured covariance, time as a random coefficient, and time × group interaction with the according likelihood-ratio tests were calculated. The linear mixed-effect regression models showed neither group effects between IG and CG at baseline nor time effects between baseline and follow-up for SDANN (24 h), SDNN (24 h and nighttime), RMSSD (24 h and nighttime), and HR (24 h and nighttime). Nighttime SDANN significantly improved in the intervention group (z = 2.04, p = 0.041) compared to the control group. The objective stress axis measures (SDANN) showed successful stress reduction due to the training. Nighttime SDANN was strongly associated with minimum HR. Though the effects were small and only visible at night, it is highly remarkable that 3 days of intervention achieved a measurable effect considering that stress is only one of many factors that can influence HR and HRV.

Comparison of Five Triage Tools for Identifying Mortality Risk and Injury Severity of Multiple Trauma Patients Admitted to the Emergency Department in the Daytime and Nighttime: A Retrospective Study

Effective triage tools are indispensable for doctors to make a prompt decision for the treatment of multiple trauma patients in emergency departments (EDs). The Modified Early Warning Score (MEWS), National Early Warning Score (NEWS), standardized early warning score (SEWS), Modified Rapid Emergency Medicine Score (mREMS), and Revised Trauma Score (RTS) are five common triage tools proposed for trauma management. However, few studies have compared these tools in a multiple trauma cohort and investigated the influence of nighttime admission on the performance of these tools. This retrospective study was aimed at evaluating and comparing the performance of MEWS, NEWS, SEWS, mREMS, and RTS for identifying the mortality risk and trauma severity of patients with multiple trauma admitted to the ED during the daytime and nighttime. Retrospective data were collected from the medical records of patients with multiple trauma admitted in the daytime or nighttime to calculate scores for each triage tool. Logistic regression analysis was conducted on each triage tool for identifying in-hospital mortality and severe trauma (injury severity score > 15) in the daytime and nighttime. The performance of the tools was evaluated and compared by calculating area under the receiver operating characteristic curve (AUROC) of the retrospective logistic model of each tool. We collected data for 1,818 admissions, including 1,070 daytime and 748 nighttime admissions. A comparison of performance for identifying in-hospital mortality between daytime and nighttime yielded the following results (AUROC): MEWS (0.95 vs. 0.93, p = 0.384), NEWS (0.95 vs. 0.94, p = 0.708), SEWS (0.95 vs. 0.94, p = 0.683), mREMS (0.94 vs. 0.92, p = 0.286), and RTS (0.93 vs. 0.93, p = 0.87). Similarly, a comparison of performance for identifying trauma severity between daytime and nighttime yielded the following results (AUROC): MEWS (0.78 vs. 0.78, p = 0.95), NEWS (0.8 vs. 0.8, p = 0.885), SEWS (0.78 vs. 0.78, p = 0.818), mREMS (0.75 vs. 0.69, p = 0.019), and RTS (0.75 vs. 0.74, p = 0.619). All five scores are excellent triage tools (AUROC ≥ 0.9) for identifying in-hospital mortality for both daytime and nighttime admissions. However, they have only moderate effectiveness (AUROC < 0.9) at identifying severe trauma. The NEWS is the best triage tool for identifying severe trauma for both daytime and nighttime admissions. The MEWS, NEWS, SEWS, and RTS exhibited no significant differences in performance for identifying in-hospital mortality or severe trauma during the daytime or nighttime. However, the mREMS was better at identifying severe trauma during the daytime.

Accuracy of the oscillometric method for the measurement of heart rate at rest and during mild exercise

OBJECTIVE

Whether oscillometric devices provide accurate measurements of heart rate (HR) is not known. Our aim was to determine the accuracy of an oscillometric device for the measurement of HR during rest and exercise.

METHODS

The Microlife WatchBP O3, a monitor previously validated for blood pressure measurement, was tested in 36 individuals from the general population (mean age, 72.9 years; 18 men). HR was measured at rest and during stress testing on a cycle ergometer in order to increase HR by 15% or more. HR was computed from the oscillometric waves recorded during the deflation phase of the blood pressure measurement and was compared with HR measured by pulse palpation by two observers.

RESULTS

At rest, the mean device-observer HR difference was 0.9 ± 2.1 bpm. During exercise, the average HR increase was 20.3% and the mean device-observer difference was 0.6 ± 2.6 bpm. The device-observer HR differences were all included within ±6 bpm both at rest and during exercise. Kappa statistics showed a very good agreement between device and observers both at rest (kappa scores, 0.82-0.88) and during exercise (kappa scores, 0.81 and 0.86). The device-observer HR differences were unrelated to the level of HR or to pulse pressure.

CONCLUSION

The present study shows that the oscillometric technique is able to provide reliable HR measurements during rest and mild exercise. Whether evaluation of HR performance should be included during validation testing of automatic monitors should be established by regulatory bodies.

Association of nocturnal subconjunctival hemorrhage and non-dipper blood pressure pattern: A benign clue for serious diseases

PURPOSE

To evaluate the association between non-dipper blood pressure pattern and subconjunctival hemorrhage (SCH).

METHODS

Twenty-seven consecutive patients with nocturnal SCH and 27 age, sex-matched controls were enrolled. Demographic, blood parameters, office blood pressure measurements, 24-h ambulatory blood pressure monitoring (ABPM) were evaluated.

RESULTS

Mean diastolic blood pressure (DBP) for nighttime (65.03 ± 7.1 vs. 70.78 ± 10.5, p: 0.22), mean heart rate for nighttime (64.54 ± 8.26 vs. 69.93 ± 9.85, p: 0.034), Minimum Systolic Blood pressure(SBP) and DBP values for nighttime (92.44 ± 9.72 vs. 99.44 ± 10.66, p:0.015 and 51.15 ± 8.31 vs. 57.7 ± 11.2, p: 0.018) were higher, nocturnal fall ratio of SBP and DBP were significantly lower in the SCH ( + ) group compared to SCH (-) group (5.38 ± 8.39 vs. 10.34 ± 6.08, p: 0.016 and 4.26 ± 8.92 vs. 13.78 ± 6.97, p < 0001 respectively). Ten patients (37%) in the SCH (-) group and 18 patients (66.7%) in the SCH ( + ) group were non-dippers (p: 0.029). Mean daytime SBP and DBP were higher compared to office measurements of 4 patients (14.8%) in the SCH (-) group and 11 patients (40.7%) in the SCH ( + ) group (p: 0.033).

CONCLUSION

SCH had a strong association with non-dipper blood pressure pattern, higher nocturnal heart rate and masked hypertension which are precursors of myocardial infarction, stroke and renal failure. So, SCH should be considered as a clue for serious diseases such as coronary artery disease, myocardial infarction, stroke and patients should be evaluated for ABPM.

Association of Night-Time Heart Rate With Ventricular Tachyarrhythmias, Appropriate and Inappropriate Implantable Cardioverter-Defibrillator Shocks

Background: Night-time heart rate (HR) is expected to reflect more accurately the cardiac autonomic function of modulating cardiovascular activity. Few studies have been conducted on the predictive values of night-time HR in relation to cardioverter-defibrillator therapies.

Aims: To explore the associations of night-time HR with the ventricular tachyarrhythmias (VTAs), appropriate and inappropriate implantable cardioverter-defibrillator (ICD) shocks.

Methods: Patients from the SUMMIT registry receiving ICD or cardiac resynchronization therapy with defibrillator (CRT-D) implantation were retrospectively analyzed using archived home monitoring data. Night-time HR was recorded from 2:00 am to 6:00 am during the first 30 to 60 days after implantation. VTA events and ICD shocks were identified using the intracardiac electrograms by two independent physicians. Restricted cubic splines and smooth curve fitting were conducted to address the non-linear associations between night-time HR and adjusted hazards for clinical outcomes.

Results: Over a mean follow-up duration of 55.8 ± 22.7 months, 187 deaths were observed among 730 patients. VTAs, appropriate and inappropriate ICD shocks were observed in 422 (57.8%), 293 (40.1%), and 72 (10.0%) patients, respectively. Apparent U-shaped non-linear associations of night-time HR with VTAs (P for non-linearity = 0.007), appropriate ICD shocks (P for non-linearity = 0.003) and inappropriate ICD shocks (P for non-linearity = 0.014) were detected. When night-time HR was beyond 60 bpm, every 1 bpm increase in night-time HR could result in 3.2, 3.3, and 4.9% higher risks of VTAs and appropriate and inappropriate ICD shocks, respectively; when night-time HR was lower than 60 bpm, every 1 bpm increase in night-time HR could result in 6.0 and 10.7% lower risks of appropriate and inappropriate ICD shocks. Compared to night-time HR of ≤ 50 or ≥70 bpm, night-time HR of 50–70 bpm was associated with 24.9, 30.2, 63.5, and 31.5% reduced incidences of VTA events, appropriate ICD shocks, inappropriate ICD shocks, and all-cause mortality, respectively.

Conclusion: Apparent non-linear associations of night-time HR with VTAs and ICD shocks were detected. An increasing incidence of VTAs and ICD shocks was observed at both low and high levels of night-time HR. Night-time HR of 50–70 bpm might be the optimal therapeutics target for the management of ICD/CRT-D recipients.

Influence of smoking and other cardiovascular risk factors on heart rate circadian rhythm in normotensive and hypertensive subjects

Circadian heart rate (HR) is influenced by hypertension and other cardiovascular risk factors particularly smoking, obesity and dyslipidemia. Until now, to evaluate the HR changes due to presence of these risk factors, a single HR office measure or a mean evaluated on day time or night time or 24h was used. However, since HR shows a circadian behavior, a single value represents only a rough approximation of this behavior. In this study, we analyzed the influence of smoking, obesity and dyslipidemia on the circadian rhythm in normotensive and hypertensive subject groups presenting only one of these risk factors. The 24h HR recordings of 170 normotensive (83 without risk factors, 20 smokers, 44 with dyslipidemia, 23 obese) and 353 hypertensive (169 without risk factors, 32 smokers, 99 with dyslipidemia, 53 obese) subjects were acquired using a Holter Blood Pressure Monitor. Results highlighted a specific circadian behavior with three characteristic periods presenting different HR means and rates of HR change in the eight subject groups. The slopes could be used both to estimate the morning HR surge associated with acute cardiovascular effects in the awakening and to evaluate the decline during the night. Moreover, we suggest to use three HR mean values (one for each identified period of the day) rather than two HR values to better describe the circadian HR behavior. Furthermore, smoking increased and dyslipidemia decreased mean HR values from 10:00 to 04:00, both in normotensive and hypertensive subjects in comparison with subjects without risk factors. In this time interval, hypertensive obese subjects showed higher values while normotensive ones presented quite similar values than subjects without risk factors. During the awakening (05:00-10:00) the slopes were similar among all groups with no significant difference among the mean HR values.

Decreased nocturnal heart rate variability and potentially related brain regions in arteriosclerotic cerebral small vessel disease

Background

To assess heart rate variability (HRV) among patients with arteriosclerotic cerebral small vessel disease (CSVD) by comparing with control subjects, and to determine whether HRV parameters were related to structural alterations in brain regions involved in autonomic regulation among CSVD patients.

Methods

We consecutively recruited subjects aged between 50 and 80 years who visited the Stroke Prevention Clinic of our hospital and have completed brain magnetic resonance imaging examination from September 1, 2018 to August 31, 2019. Polysomnography and synchronous analyses of HRV were then performed in all participants. Multivariable binary logistic regression was used to identify the relationship between HRV parameters and CSVD. Participants were invited to further undergo three-dimensional brain volume scan, and the voxel based morphometry (VBM) analysis was used to identify gray matter atrophy.

Results

Among 109 participants enrolled in this study, 63 were assigned to the arteriosclerotic CSVD group and 46 to the control group. Lower standard deviation of normal-to-normal intervals (SDNN, OR = 0.943, 95% CI 0.903 to 0.985, P = 0.009) and higher ratio of low to high frequency power (LF/HF, OR = 4.372, 95% CI 1.033 to 18.508, P = 0.045) during the sleep period were associated with CSVD, independent of traditional cerebrovascular risk factors and sleep disordered breathing. A number of 24 CSVD patients and 21 controls further underwent three-dimensional brain volume scan and VBM analysis. Based on VBM results, SDNN during the awake time (β = 0.544, 95% CI 0.211 to 0.877, P = 0.001) and the sleep period (β = 0.532, 95% CI 0.202 to 0.862, P = 0.001) were both positively related with gray matter volume within the right inferior frontal gyrus only among CSVD patients.

Conclusions

Decreased nocturnal HRV is associated with arteriosclerotic CSVD independent of traditional cerebrovascular risk factors and sleep disordered breathing. The structural atrophy of some brain regions associated with cardiac autonomic regulation sheds light on the potential relationship.

Trial registration

Trial registration number: ChiCTR1800017902. Date of registration: 20 Aug 2018.

Sleep and Cardiovascular Risk

Sleep is essential for healthy being and healthy functioning of human body as a whole, as well as each organ and system. Sleep disorders, such as sleep-disordered breathing, insomnia, sleep fragmentation, and sleep deprivation are associated with the deterioration in human body functioning and increased cardiovascular risks. However, owing to the complex regulation and heterogeneous state sleep per se can be associated with cardiovascular dysfunction in susceptible subjects. The understanding of sleep as a multidimensional concept is important for better prevention and treatment of cardiovascular diseases.

Resting Heart Rate as a Cardiovascular Risk Factor in Hypertensive Patients: An Update

A large body of evidence has shown that resting heart rate (RHR) holds important prognostic information in several clinical conditions. In the majority of the general population studies, a graded association between RHR and mortality from all causes, cardiovascular (CV) disease, ischemic heart disease, and stroke has been observed. These associations appeared even stronger and more consistent in hypertensive patients. Studies performed with 24-hour ambulatory recording have shown that an elevated nighttime heart rate may confer an additional risk on top of office RHR. The mechanisms by which tachycardia alone or in association with sympathetic overactivity induces CV damage are well understood. Fast RHR is a strong predictor of future hypertension, metabolic disturbances, obesity, and diabetes. Several experimental lines of research point to high RHR as a main risk factor for the development of atherosclerosis, large artery stiffness, and CV disease. Elevated RHR is a common feature in patients with hypertension. Thus, there is a large segment of the hypertensive population that would benefit from a treatment able to decrease RHR. Improvement of unhealthy lifestyle should be the first goal in the management of the hypertensive patient with elevated RHR. Most clinical guidelines now recommend the use of combination therapies even in the initial treatment of hypertension. Although no results of clinical trials specifically designed to investigate the effect of RHR lowering in human beings without CV diseases are available, in hypertensive patients with high RHR a combination therapy including a cardiac slowing drug at optimized dose seems a sensible strategy. Tachycardia can be considered both as a marker of sympathetic overactivity and as a risk factor for cardiovascular events. In this sketch, the main cardiovascular and metabolic effects of increased sympathetic tone underlying high heart rate are shown. The link between tachycardia and cardiovascular events can be explained also by the direct hemodynamic action of heart rate on the arteries and the left ventricular (LV) wall.

Prognostic impact of mean heart rate by Holter monitoring on long-term outcome in patients with ST-segment elevation myocardial infarction undergoing percutaneous coronary intervention

BACKGROUND

Previous studies have shown elevated admission heart rate (HR) was associated with worse outcome in patients with myocardial infarction (MI). However, the prognostic value of mean heart rate (MHR) with Holter monitoring remains unclear.

OBJECTIVES

Our present study aims to evaluate the impact of MHR by Holter monitoring on long-term mortality in patients with ST-segment elevation myocardial infarction (STEMI).

METHODS

1013 STEMI patients were divided into four groups according to the quartiles of MHR by Holter monitoring, Q1 (< 66 bpm), Q2 66-72 bpm), Q3 (73-78 bpm), and Q4 (> 78 bpm). The endpoint was long-term all-cause mortality. The predictive value of admission HR, discharge HR, and MHR was compared with receiver operating characteristic (ROC) curves.

RESULTS

Patients in Q4 were more likely to present with anterior MI, high Killip class, relatively lower admission blood pressure, significantly increased troponin I, B-type natriuretic peptide, and decreased left ventricular ejection fraction. During a median of 28.3 months follow up period, 91 patients (8.9%) died. The mortality in Q4 was significantly higher than in the other three groups (P < 0.001). After multivariate adjustment, Q4 was associated with a 1.0-fold increased risk of long-term all-cause mortality (HR = 2.096, 95% CI 1.190-3.691, P = 0.010). ROC analysis shows MHR with Holter (AUC = 0.672) was superior to admission HR (AUC = 0.556) or discharge HR (AUC = 0.578).

CONCLUSIONS

MHR based on Holter monitoring provided important prognostic value and MHR > 78 bpm was independently associated with increased risk of long-term all-cause mortality in patients with STEMI, and its predictive validity was superior to admission or discharge HR.

Elevated heart rate and cardiovascular risk in hypertension

Epidemiological studies have shown that chronically elevated resting heart rate (HR) is significantly associated with organ damage, morbidity and mortality in a wide range of patients including hypertensive patients. Evidence is also available that an increased HR reflects sympathetic nervous system overdrive which is also known to adversely affect organ structure and function and to increase the risk of unfavourable outcomes in several diseases. The causal relationship between elevated HR, organ damage, and cardiovascular outcomes can thus be explained by its relationship with sympathetic cardiovascular influences although evidence of sympathetically-independent adverse effect of HR increases per se makes it more complex. Interventions that target HR by modulating the sympathetic nervous system have therefore a strong pathophysiological and clinical rationale. As most clinical guidelines now recommend the use of combination therapies in patients with hypertension, it might be desirable to consider as combination components drugs which lower HR, if HR is elevated such as, according to guideliines, when it is above 80 b/min.

Heart rate as a predictor of cardiovascular risk

Heart rate is a parameter that is very easy to measure and is widely used both in clinic and during daily life activities. Its value gained more relevance with the evidence, in prospective studies and meta-analysis, of association between elevated heart rate values and diseases and outcomes.The increased knowledge of physiological mechanisms of heart rate control and the pathophysiological mechanisms responsible for its dysfunction allows to identify the cut-off value of normalcy providing info for non-pharmacological and pharmacological treatments to reduce the cardiovascular risk both in general population and in pathophysiological conditions. This paper overviews the knowledges of the role of resting heart rate as predictor of cardiovascular risk.

Feasible assessment of recovery and cardiovascular health: accuracy of nocturnal HR and HRV assessed via ring PPG in comparison to medical grade ECG

OBJECTIVE

To validate the accuracy of the Oura ring in the quantification of resting heart rate (HR) and heart rate variability (HRV).

BACKGROUND

Wearable devices have become comfortable, lightweight, and technologically advanced for assessing health behavior. As an example, the novel Oura ring integrates daily physical activity and nocturnal cardiovascular measurements. Ring users can follow their autonomic nervous system responses to their daily behavior based on nightly changes in HR and HRV, and adjust their behavior accordingly after self-reflection. As wearable photoplethysmogram (PPG) can be disrupted by several confounding influences, it is crucial to demonstrate the accuracy of ring measurements.

APPROACH

Nocturnal HR and HRV were assessed in 49 adults with simultaneous measurements from the Oura ring and the gold standard ECG measurement. Female and male participants with a wide age range (15-72 years) and physical activity status were included. Regression analysis between ECG and the ring outcomes was performed.

MAIN RESULTS

Very high agreement between the ring and ECG was observed for nightly average HR and HRV (r² = 0.996 and 0.980, respectively) with a mean bias of -0.63 bpm and -1.2 ms. High agreement was also observed across 5 min segments within individual nights in (r² = 0.869 ± 0.098 and 0.765 ± 0.178 in HR and HRV, respectively).

SIGNIFICANCE

Present findings indicate high validity of the Oura ring in the assessment of nocturnal HR and HRV in healthy adults. The results show the utility of this miniaturised device as a lifestyle management tool in long-term settings. High quality PPG signal results prompt future studies utilizing ring PPG towards clinically relevant health outcomes.

High Nighttime Heart Rate is Associated with Increased Risk of All-Cause Mortality in Patients with Heart Failure and Reduced Ejection Fraction

High heart rate (HR) is associated with increased risks of adverse outcomes in patients with heart failure. This study aimed to evaluate which measures of HR were associated with all-cause mortality in patients with heart failure and reduced ejection fraction (HFrEF). This study involved 741 HFrEF patients (age 65.1 ± 14.7 years, 71% male) who underwent 24 hour Holter electrocardiogram and resting electrocardiogram within 7 days between 2011 and 2015. We examined the associations of resting, 24 hour, and nighttime HRs with all-cause mortality. Nighttime and 24 hour HRs were determined as the mean HRs between 11:00 p.m. and 7:00 a.m. and over 24 hours, respectively. Nighty patients (12.1%) died during the 2-year follow-up. Resting, nighttime, and 24 hour HRs were significantly associated with all-cause mortality, also after adjusting for conventional risk factors. Resting HR did not remain as an independent factor when 24 hour HR (hazard ratio 1.10, 95% confidence interval 1.04-1.18) was included in the model. Including nighttime HR (hazard ratio 1.11, 95% confidence interval 1.05-1.17) in the model also eliminated 24 hour HR as an independent variable. Compared with the lowest quartile of nighttime HR (< 65 beats/minute), the highest quartile of nighttime HR (> 87 beats/minute) was significantly associated with a higher risk of all-cause mortality (hazard ratio 2.89, 95% CI 1.49-5.60). In conclusion, 24 hour HR and nighttime HR were significantly associated with an increased risk of mortality in patients with HFrEF. Nighttime HR appeared to be more strongly associated with all-cause mortality compared with 24 hour HR.

Failure to de-arouse during sleep-onset transitions in the heart rates of individuals with sleep-onset insomnia

OBJECTIVE

Increased cardiovascular risk associated with sleep-onset insomnia has been reported, but the patterns of heart rate (HR) transitions during sleep onset in individuals with sleep-onset insomnia remain uncertain. This study explored the HR dynamics during objective and subjective sleep onset transitions among sleep-onset insomnia.

METHODS

Seventeen good sleepers and 17 individuals with sleep-onset insomnia had their night-time HR measured. HR and heart rate variability (HRV) were analyzed within 8-min periods of pre- and post-transition of stage N1, stage N2 and subjective sleep onset.

RESULTS

A significantly higher low-frequency percentage of HRV was observed in pre-N1 period among insomnia group, compared with good sleepers. Decline in HR begins in 160 s prior to N1 onset among good sleepers, whereas the HRs of insomnia group were reduced only after N1 onset in comparison to their HRs at the time of N1 onset. The good sleepers and insomnia group both had their HRs dropped to a level comparable to their HRs at respective stage N2 onset at 220 s and 80 s prior to N2 onset. No differences in HR was found during subjective sleep onset transition in both groups.

CONCLUSION

During the wake-to-sleep transition, a low and stable HR was observed before cortical alternations in good sleepers; however, a consistently high HR until N1 onset was shown among sleep-onset insomnia. This finding suggests a state-dependent and failure to de-arouse from the high arousal level of wakefulness into light sleep is associated with sleep initiation difficulty.

Accuracy of PurePulse photoplethysmography technology of Fitbit Charge 2 for assessment of heart rate during sleep

Elevated asleep heart rate (HR) is a risk factor for cardiovascular disease and other-cause morbidity and mortality. We assessed the accuracy of Fitbit Inc. PurePulse® photoplethysmography with reference to three-lead electrocardiography (ECG) in determining HR during sleep. HR of 35 (17 female) healthy adults 25.1 ± 10.6 years of age (mean ± SD) was continuously recorded throughout a single night of sleep. There was no significant difference in asleep HR mean (0.09 beats per minute [bpm], P = 0.426) between Fitbit photoplethysmography and ECG; plus, there was excellent intraclass correlation (0.998) and narrow Bland-Altman agreement range (2.67 bpm). The regression analysis of Bland-Altman plot of mean asleep HR indicates Fitbit tends to slightly overestimate reference values in the lower range of HR (HR < 50 bpm) by 0.51 bpm and slightly underestimate reference values in the higher range of HR (HR > 80 bpm) by 0.63 bpm. Mixed model analysis of epoch-by-epoch (5-min epochs) asleep HR showed significant "U" shape trend (P < 0.001) in amount of Fitbit error (absolute amount of difference between ECG and Fitbit values regardless of overestimation or underestimation) in regard to HR, i.e. smaller error in the medium range of HR (60-80 bpm) and slightly larger error for lower (<60 bpm) and higher (>80 bpm) ranges of HR. However, effect of age, body mass index, gender, and subjective sleep quality measured by Pittsburgh sleep quality index (good/poor sleepers) on error in estimating HR by the Fitbit method was not significant. It is concluded that Fitbit photoplethysmography suitably tracks HR during sleep in healthy young adults.

Nocturnal pulse rate correlated with ambulatory blood pressure and target organ damage in patients with chronic kidney disease

The relationship between resting pulse rate (PR) and the occurrence of hypertension and cardiovascular (CV) mortality has been described in the general population. Few studies have examined the relationship between ambulatory PR, ambulatory blood pressure (BP), and target organ damage (TOD) in patients with chronic kidney disease (CKD). A total of 1509 patients with CKD were recruited in our hospital. Ambulatory blood pressure monitoring (ABPM) over a 24-hours period was performed and referenced with clinical data in this cross-sectional study. TOD was measured by estimated glomerular filtration rate (eGFR), left ventricular hypertrophy (LVH), and carotid intima-media thickness (cIMT). Univariate and multivariate analyses were used to evaluate the relationship between PR, BP, and TOD. The percentage of male patients was 58.3% with a mean age of 44.6 ± 16.2 years. Nocturnal PR rather than 24-hours PR or daytime PR was an independent risk factor for clinical hypertension, 24-hours hypertension, BP dipper state, poor renal function, and LVH. In addition, the authors found that nighttime PR >74 beats/min (bpm) group was independently associated with clinical hypertension, 24-hours hypertension, day and night hypertension, nondipping BP, lower eGFR, and LVH when compared with nighttime PR <64 bpm group. Furthermore, 1:1 propensity score matching between PR ≤74 bpm group and PR >74 bpm group was performed. Multivariate analyses indicated nighttime PR >74 bpm remained independently associated with clinical hypertension, daytime and nighttime hypertension, and LVH. An increased nocturnal PR is associated with TOD, higher BP, and nondipping BP in patients with CKD.

Blood pressure, heart rate, and double product in a pooled cohort: the Japan Arteriosclerosis Longitudinal Study

OBJECTIVE

To identify the characteristics of blood pressure (BP), heart rate (HR), and double product in a Japanese population sample.

METHODS

We pooled individual records from 1999 to 2005 for 111 007 participants in 25 community-based cohorts and seven worksite-based cohorts. The data were analyzed to provide information on BP, HR, and double product according to age-sex groups and use of antihypertensive medication.

RESULTS

Average BP was 130/77 mmHg among men and women combined. Among untreated individuals, SBP increased with age, whereas DBP reached a ceiling around the age of 60 years. The average SBP of treated participants was around 140 mmHg, irrespective of age, whereas DBP decreased linearly with age, and 56.4% of treated participants had a BP of 140/90 mmHg or over. HR did not differ across age groups or treatment status. The double product, also called the rate-pressure product, calculated by multiplying the SBP and the HR, increased with age among untreated individuals, whereas it first decreased and then increased with age among treated individuals.

CONCLUSION

Based on these collaborative data, insufficient BP control in Japan, where the average life expectancy is the longest in the world, was seen.

Heart rate as a predictor of cardiovascular risk

BACKGROUND

Heart rate (HR) is a predictor of cardiovascular, cerebrovascular and all-cause mortality in the general population, as well as in patients with cardio- and cerebrovascular diseases. We aimed to summarize current knowledge regarding the influence of HR on cardio- and cerebrovascular morbidity and mortality.

MATERIALS AND METHODS

PubMed, MEDLINE, Ovid and EMBASE databases were searched for large follow-up studies or meta-analysis published between January 1990 and September 2017 in the English language using the following keyword "heart rate," "resting heart rate," "mortality," "outcome," "hypertension," "heart failure," "ischaemic heart disease," "coronary heart disease" and "stroke."

RESULTS

The relationship between increased HR and cardio- and cerebrovascular morbidity and mortality has been reported in a large number of studies, and the results regarding this association are concurrent. This connection is generally stronger in men than in women. The increase in HR usually occurs in parallel with elevation of blood pressure and metabolic disturbances (insulin resistance, dyslipidaemia). However, even after adjustment for the most important cardiovascular risk factors, HR remained an independent predictor of adverse events in global population or in patients with cardio- and cerebrovascular diseases.

CONCLUSION

HR has an important negative effect on cardio- and cerebrovascular morbidity and mortality. Future longitudinal investigations should clarify HR significance and optimal HR reduction for primary and secondary prevention in cardio- and cerebrovascular events.

Does resting heart rate measured by the physician reflect the patient's true resting heart rate? White-coat heart rate

OBJECTIVES

In cardiology, resting heart rate (HR) and blood pressure (BP) are key elements and are used to adapt treatment. However HR measured in consultation may not reflect true resting HR. We hypothesize that there may be a "white-coat" effect like with BP and that there may be an association between HR variations and BP variations.

METHODS

This prospective, monocentric, observational, pilot study (January-April 2016) included 57 consecutive ambulatory patients at Poitiers University Hospital, France (58% male, mean age 64 years). Patients' resting HR and BP were recorded with the same automated blood pressure sphygmomanometer in consultation by the physician then with self-measurement at home.

RESULTS

In the overall cohort, we found that HR was significantly higher in consultation (70.5bpm±12.6 vs. 68.1bpm±10.1, p=0.034). HR also correlated with diastolic BP (r=0.45, p=0.001). Patients were divided into three groups to look for associations with BP: masked HR, (higher HR at home, 38.6%), white-coat HR, (lower HR at home 52.6%) and iso HR, (no change between HR at home and consultation, 8.8%). Although there was no difference between groups in diastolic BP measured in consultation, home diastolic BP was lower in the white-coat HR group (74.3mmHg±9.8 vs. 77.9mmHg±7.5, p=0.016).

CONCLUSIONS

Our study brings to light an exciting idea that could have a major therapeutic and maybe prognostic impact in cardiology: resting HR measured by the physician in consultation does not reflect true resting HR. This must be taken into account to adapt treatment.

Association Between Heart Rate and Subclinical Cerebrovascular Disease in the Elderly

BACKGROUND AND PURPOSE

Although increased heart rate (HR) is a predictor of cardiovascular events and mortality, its possible association with subclinical cerebrovascular disease, which is prevalent in the elderly, has not been evaluated. This study aimed to investigate the association of daytime, nighttime, 24-hour HR, and HR variability with subclinical cerebrovascular disease in an elderly cohort without history of stroke.

METHODS

The study cohort consisted of 680 participants (mean age, 73±7 years; 42% men) in sinus rhythm who underwent 24-hour ambulatory blood pressure and HR monitoring, 2-dimensional echocardiography, and brain magnetic resonance imaging as part of the CABL study (Cardiac Abnormalities and Brain Lesion). Subclinical cerebrovascular disease was defined as silent brain infarcts and white matter hyperintensity volume (WMHV). The relationship of HR measures with the presence of silent brain infarct and upper quartile of log WMHV (log WMHV4) was analyzed.

RESULTS

Presence of silent brain infarct was detected in 93 participants (13.7%); mean log WMHV was -0.92±0.93 (median, -1.05; min, -5.88; max, 1.74). Multivariate analysis showed that only nighttime HR (adjusted odds ratio, 1.29 per 10 bpm; 95% confidence interval, 1.03-1.61; P=0.026) was significantly associated with log WMHV4, independent of traditional cardiovascular risk factors, ambulatory systolic blood pressure, and echocardiographic parameters. No similar association was observed for daytime HR and HR variability. There was no significant association between all HR measures and silent brain infarct.

CONCLUSIONS

In a predominantly elderly cohort, elevated nighttime HR was associated with WMHV, suggesting an independent role of HR in subclinical cerebrovascular disease.

Heart Rate and Blood Pressure: "Connecting the Dots" in Epidemiology and Pathophysiology

There is robust evidence from epidemiological and clinical studies showing that elevated heart rate (HR) constitutes a powerful predictor of morbidity and mortality in patients with hypertension, underlining the significance of HR measurement in them. Autonomous nervous system dysfunction and atherosclerosis are important features in the pathogenesis of the untoward events. However, the relationship between HR and blood pressure (BP) is complex and differs depending on the type of BP measurement which is considered. This differentiation implicates complex physiological mechanisms and is of clinical importance regarding the divergent effect of the different types of antihypertensive agents on these parameters. The aim of this review is to summarize the current evidence on the relationship between HR and BP based on epidemiological, clinical, and experimental studies.

Glomerular hyperfiltration is a predictor of adverse cardiovascular outcomes

The association between glomerular hyperfiltration and cardiovascular events is not well known. To investigate whether glomerular hyperfiltration is independently associated with risk of adverse outcome we analyzed 8794 participants, average age 52 years enrolled in 8 prospective studies. Of these, 89% had hypertension. Using the 5th and 95th percentiles of the age- and sex-specific quintiles of CKD-EPI-calculated estimated glomerular filtration rate (eGFR), we identified three participant groups with low, high and normal eGFR. The ambulatory pulse pressure interval was wider and nighttime blood pressure fall was smaller in both the low and high than in the normal eGFR participants. During a mean follow-up of 6.2 years, there were 722 cardiovascular events. Crude event rates were significantly higher for both high (1.8 per 100-person-year) and low eGFR groups (2.1 per 100 person-year) as compared with group with normal eGFR (1.2 per 100 person-year). In multivariable Cox models including age, sex, average 24-hour blood pressure, smoking, diabetes, and cholesterol, both high eGFR (hazard ratio 1.5 (95% confidence interval 1.2-2.1) and low eGFR (2.0 [1.5-2.6]) participants had a significantly higher risk of cardiovascular events as compared to those with normal eGFR. Addition of body mass index to the multivariable survival model did not change the magnitude of hazard estimates. Thus, glomerular hyperfiltration is a strong and independent predictor of cardiovascular events in a large multiethnic population of predominantly hypertensive individuals. Our findings support a U-shaped relationship between eGFR and adverse outcome.

Management of the hypertensive patient with elevated heart rate: Statement of the Second Consensus Conference endorsed by the European Society of Hypertension

In June 2015, a panel of experts gathered in a consensus conference to plan updating recommendations on the management of the hypertensive patient with elevated heart rate (HR), previously released in 2006. The issues examined during that meeting and further discussed by the participants during the following months involved the assessment of HR, the relevance of HR as a cardiovascular risk factor, the definition of tachycardia and the treatment of the hypertensive patient with high HR. For the measurement of resting HR the panel experts recommended that scientific investigations focusing on HR should report information on length of resting period before measurement, information about temperature and environment, method of measurement, duration of measurement, number of readings, time interval between measurements, body position and type of observer. According to the panellists there is convincing evidence that HR is an important risk factor for cardiovascular disease and they suggest to routinely include HR measurement in the assessment of the hypertensive patient. Regarding the definition of tachycardia, the panellists acknowledged that in the absence of convincing data any threshold used to define tachycardia is arbitrary. Similarly, as there are no outcome studies of HR lowering in tachycardia hypertension, the panellists could not make practical therapeutic suggestions for the management of such patients. However, the experts remarked that absence of evidence does not mean evidence against the importance of tachycardia as a risk factor for cardiovascular disease and that long-term exposure to a potentially important risk factor may impair the patient's prognosis. The main aims of the present document are to alert researchers and physicians about the importance of measuring HR in hypertensive patients, and to stimulate research to clarify unresolved issues.

Associations between actigraphy-assessed sleep, inflammatory markers, and insulin resistance in the Midlife Development in the United States (MIDUS) study

BACKGROUND

Disturbed sleep has been associated with increased insulin resistance and elevated inflammation. Although there is growing body of evidence that activation of inflammatory pathways plays a crucial role in the development of insulin resistance, the mediational model whereby sleep disturbances influence inflammation that drives insulin resistance has not been fully assessed in general population studies with objectively measured sleep. This study aimed to examine associations between objectively measured sleep, inflammatory markers, and insulin resistance simultaneously and in a mediational analysis, thereby offering insights into the possible causal model.

METHODS

Cross-sectional data collected from 2004 to 2009 during the Midlife Development in the United States II biomarker project were used. The study population included 374 community-based participants (138 men and 236 women) who completed seven nights of wrist actigraphy. Multiple regressions controlling for age and statistically significant variables in univariate regressions were performed to evaluate the associations between actigraphy-assessed sleep measures, inflammatory cytokines, and insulin resistance.

RESULTS

The regression models showed that in women, higher sleep onset latency (SOL) was associated with higher insulin resistance after controlling for age, smoking, obesity, diabetes, depression, and inflammatory cytokines. Higher SOL was also associated with higher interleukin (IL)-6 and C-reactive protein (CRP) levels in women, but no association was found in men. Using mediation models in women, the association between SOL and insulin resistance was partially explained by the indirect effect of inflammatory cytokines.

CONCLUSION

A combination of inflammation and other unidentified pathways may contribute to the relationship between disturbed sleep and glucose homeostasis.

Association between resting heart rate and coronary artery disease, stroke, sudden death and noncardiovascular diseases: a meta-analysis

BACKGROUND

Resting heart rate is linked to risk of coronary artery disease, stroke, sudden death and noncardiovascular diseases. We conducted a meta-analysis to assess these associations in general populations and in populations of patients with hypertension or diabetes mellitus.

METHODS

We searched PubMed, Embase and MEDLINE from inception to Mar. 5, 2016. We used a random-effects model to combine study-specific relative risks (RRs). We used restricted cubic splines to assess the dose-response relation.

RESULTS

We included 45 nonrandomized prospective cohort studies in the meta-analysis. The multivariable adjusted RR with an increment of 10 beats/min in resting heart rate was 1.12 (95% confidence interval [CI] 1.09-1.14) for coronary artery disease, 1.05 (95% CI 1.01-1.08) for stroke, 1.12 (95% CI 1.02-1.24) for sudden death, 1.16 (95% CI 1.12-1.21) for noncardiovascular diseases, 1.09 (95% CI 1.06-1.12) for all types of cancer and 1.25 (95% CI 1.17-1.34) for noncardiovascular diseases excluding cancer. All of these relations were linear. In an analysis by category of resting heart rate (< 60 [reference], 60-70, 70-80 and > 80 beats/min), the RRs were 0.99 (95% CI 0.93-1.04), 1.08 (95% CI 1.01-1.16) and 1.30 (95% CI 1.19-1.43), respectively, for coronary artery disease; 1.08 (95% CI 0.98-1.19), 1.11 (95% CI 0.98-1.25) and 1.08 (95% CI 0.93-1.25), respectively, for stroke; and 1.17 (95% CI 0.94-1.46), 1.31 (95% CI 1.12-1.54) and 1.57 (95% CI 1.39-1.77), respectively, for noncardiovascular diseases. After excluding studies involving patients with hypertension or diabetes, we obtained similar results for coronary artery disease, stroke and noncardiovascular diseases, but found no association with sudden death.

INTERPRETATION

Resting heart rate was an independent predictor of coronary artery disease, stroke, sudden death and noncardiovascular diseases over all of the studies combined. When the analysis included only studies concerning general populations, resting heart rate was not associated with sudden death.

Comparison of bisoprolol to a metoprolol CR/ZOK tablet for control of heart rate and blood pressure in mild-to-moderate hypertensive patients: the CREATIVE study

This open-label study investigated the long action of bisoprolol compared with metoprolol CR/ZOK for controlling the mean dynamic heart rate (HR) and blood pressure (BP) in patients with mild-to-moderate primary hypertension. Patients from seven centers in China were treated with either bisoprolol 5 mg or metoprolol CR/ZOK 47.5 mg once daily for 12 weeks. The primary end points were the mean dynamic HR reduction and the mean dynamic diastolic BP (DBP) control in the last 4 h of the treatment period. Secondary end points included ambulatory monitoring of the BP and HR, safety and compliance. A total of 186 patients, with 93 patients in each group, were enrolled and analyzed. In the last 4 h of the treatment period, patients receiving bisoprolol demonstrated a significantly greater reduction in the mean dynamic HR compared with patients receiving metoprolol CR/ZOK (least squares means (LSmeans) of difference: -3.79 b.p.m.; 97.5% confidence interval (CI): -7.45, -0.14; P=0.0202). Furthermore, in the last 4 h of the treatment period, bisoprolol demonstrated non-inferiority vs. metoprolol CR/ZOK in lowering the mean dynamic DBP (LSmeans of difference: -1.00; 97.5% CI: -4.79, 2.78; P=0.5495). Bisoprolol further significantly lowered the 24-h mean ambulatory, mean daytime and mean nighttime HR. The overall adverse event rate was similar between the two groups. Noncompliance was reported in 3 (3.53%) and 6 (7.32%) patients in the bisoprolol and metoprolol CR/ZOK groups, respectively. In conclusion, bisoprolol provided superior dynamic HR reduction and non-inferior dynamic BP reduction vs. metoprolol CR/ZOK in patients with mild-to-moderate hypertension. No new safety concerns were found.

Autonomic Dysfunction: How to Identify and When to Treat?

Cardiovascular autonomic dysfunction (AD) is a particular condition that can be detected by means of ambulatory blood pressure monitoring (ABPM). ABPM is helpful to identify some specific characteristics of haemodynamic AD, including non-dipping/reverse-dipping pattern, orthostatic and post-prandial hypotension and elevated blood pressure variability. These characteristics may be misdiagnosed with traditional, clinic blood pressure measurements. AD is relatively common in the real world. By analysing about 1000 recordings in a Cardiology unit, AD was found in 6.8 % of the exams. Several diseases may be the underlying causes of AD. In our sample half of the subjects were diabetic (54.4 %), 17.7 % were patients with alpha-synucleinopathy (Parkinson disease or multiple system atrophy), and 27.9 % had other underlying causes of AD including chronic kidney disease, α-lytic drug assumption and AD from unknown causes. According to the different aetiology, different clinical characteristics can be found, in particular in diabetics these peculiar aspects are less pronounced compared to the other subgroups. These characteristics have been found to be predictors of cardiovascular events, organ damage, and mortality. For these reasons, early identification of these behaviours is important, in order to better define patient's cardiovascular risk profile. As regard treatment of AD, several drugs have been tested, however none of this showed efficacy in all kinds of patients. Another open aspect is "safe" reference values for supine hypertension.

Association of ambulatory heart rate and atherosclerosis risk factors with blood pressure in young non-hypertensive adults

OBJECTIVE

The study objective was to assess the association between 24 h ambulatory heart rate (HR), atherosclerosis risk factors and blood pressure (BP) in young non-hypertensive patients.

METHODS

We recruited 186 participants aged 18-45 years from a large urban academic Family Medicine outpatient practice, serving 40 000 individuals for this observational study. The main analyses were based on multiple linear regression, with mean 24 h BP (systolic BP (SBP) or diastolic BP (DBP)) as the outcomes, mean 24 h HR as the main predictor of interest, and controlling for age, gender, race, insulin sensitivity/resistance and endothelial function measured by strain gauge venous occlusion plethysmography.

RESULTS

HR was independently associated with mean 24 h SBP and DBP (SBP and DBP: p=0.042 and 0.001, respectively). In our analyses, associations were markedly stronger for ambulatory compared with office BP measurements. Endothelial dysfunction was associated with higher SBP (p=0.013); plasminogen activator inhibitor-1 was significantly associated with both SBP and DBP (p=0.041 and 0.015, respectively), while insulin resistance was not associated with either SBP or DBP. Insulin resistance and C reactive protein were significant predictors of HR (p=0.013 and 0.007, respectively).

CONCLUSIONS

These findings suggest that HR may be a potential marker of elevated cardiovascular risk in young asymptomatic individuals, prior to the development of clinical hypertension or cardiovascular disease.

The association between prolonged sleep onset latency and heart rate dynamics among young sleep-onset insomniacs and good sleepers

A blunting of heart rate (HR) reduction during sleep has been reported to be associated with increased all-cause mortality. An increased incident of cardiovascular events has been observed in patients with insomnia but the relationship between nighttime HR and insomnia remains unclear. Here we investigated the HR patterns during the sleep onset period and its association with the length of sleep onset latency (SOL). Nineteen sleep-onset insomniacs (SOI) and 14 good sleepers had their sleep analyzed. Linear regression and nonlinear Hilbert-Huang transform (HHT) of the HR slope were performed in order to analyze HR dynamics during the sleep onset period. A significant depression in HR fluctuation was identified among the SOI group during the sleep onset period when linear regression and HHT analysis were applied. The magnitude of the HR reduction was associated with both polysomnography-defined and subjective SOL; moreover, we found that the linear regression and HHT slopes of the HR showed great sensitivity with respect to sleep quality. Our findings indicate that HR dynamics during the sleep onset period are sensitive to sleep initiation difficulty and respond to the SOL, which indicates that the presence of autonomic dysfunction would seem to affect the progress of falling asleep.

Impact of nocturnal heart rate variability on cerebral small-vessel disease progression: a longitudinal study in community-dwelling elderly Japanese

Recent evidence has shown an effect of ambulatory heart rate (HR) on cardiovascular events and mortality. Our objective was to determine whether ambulatory HR was related to the progression of cerebral small-vessel disease (SVD) or cognitive decline in community-dwelling elderly people. A cohort of 190 community-dwelling elderly people underwent an ambulatory blood pressure monitoring (ABPM), brain magnetic resonance imaging (MRI) and cognitive testing at baseline, with MRI and cognitive tests repeated 4 years later. HR variability in ABPM was quantified by the s.d. (s.d. and the root mean square of successive differences (RMSSD), and the relationship between HR variability and the progression of SVD/cognitive decline was investigated. We also assessed the association of nighttime HR variability and nocturnal HR dipping. The nighttime RMSSD of participants with the progression of SVD was significantly higher than that of those without progression of SVD (P<0.05). Moreover, nighttime RMSSD was independently associated with the progression of SVD (1 b.p.m. increment: odds ratio=1.13, 95% confidence interval=1.04-1.24, P<0.01). We failed to confirm an association between cognitive decline and nighttime HR variability. However, s.d. in the daytime and 24-h HR were independently related to cognitive decline (P<0.05). Nocturnal HR dipping was least in the top quartiles of nighttime HR variability, with a monotonic trend of nocturnal HR dipping that was dependent on the quartiles of nighttime HR variability indices (P<0.01). Increased HR variability during the night is a predictor of the progression of SVD in community-dwelling elderly people.