Circadian Pattern Of Heart Rate Research Articles

Circadian patterns of heart rate, respiratory rate and skin temperature in hospitalized COVID-19 patients.

Vital signs follow circadian patterns in both healthy volunteers and critically ill patients, which seem to be influenced by disease severity in the latter. In this study we explored the existence of circadian patterns in heart rate, respiratory rate and skin temperature of hospitalized COVID-19 patients, and aimed to explore differences in circadian rhythm amplitude during patient deterioration. We performed a retrospective study of COVID-19 patients admitted to the general ward of a tertiary hospital between April 2020 and March 2021. Patients were continuously monitored using a wireless sensor and fingertip pulse oximeter. Data was divided into three cohorts: patients who recovered, patients who developed respiratory insufficiency and patients who died. For each cohort, a population mean cosinor model was fitted to detect rhythmicity. To assess changes in amplitude, a mixed-effect cosinor model was fitted. A total of 429 patients were monitored. Rhythmicity was observed in heartrate for the recovery cohort (p<0.001), respiratory insufficiency cohort (p<0.001 and mortality cohort (p = 0.002). Respiratory rate showed rhythmicity in the recovery cohort (p<0.001), but not in the other cohorts (p = 0.18 and p = 0.51). Skin temperature also showed rhythmicity in the recovery cohort (p<0.001), but not in the other cohorts (p = 0.22 and p = 0.12). For respiratory insufficiency, only the amplitude of heart rate circadian pattern increased slightly the day before (1.2 (99%CI 0.16-2.2, p = 0.002)). In the mortality cohort, the amplitude of heart rate decreased (-1.5 (99%CI -2.6- -0.42, p<0.001)) and respiratory rate amplitude increased (0.72 (99%CI 0.27-1.3, p = 0.002) the days before death. A circadian rhythm is present in heart rate of COVID-19 patients admitted to the general ward. For respiratory rate and skin temperature, rhythmicity was only found in patients who recover, but not in patients developing respiratory insufficiency or death. We found no consistent changes in circadian rhythm amplitude accompanying patient deterioration.

Secondhand tobacco smoke, arterial stiffness, and altered circadian blood pressure patterns are associated with lung inflammation and oxidative stress in rats

Chronic smoking and secondhand tobacco smoke exposure are major risk factors for cardiovascular disease that are known to adversely alter the structural and mechanical properties of arteries. The objective of this study was to determine the effects of subchronic secondhand tobacco smoke exposure on circadian blood pressure patterns, arterial stiffness, and possible sources of oxidative stress in conscious, unsedated radiotelemetry-implanted rats. Pulse wave change in pressure over time (dP/dt) was used an indicator of arterial stiffness and was compared with both structural (wall thickness) and functional (nitric oxide production and bioactivity and endothelin-1 levels) features of the arterial wall. In addition, histology of lung, heart, and liver was examined as well as pulmonary and hepatic detoxifying enzyme activity (cytochrome P450, specifically CYP1A1). Subchronic secondhand tobacco smoke exposure altered the circadian pattern of heart rate and blood pressure, with a loss in the normal dipping pattern of blood pressure during sleep. Secondhand tobacco smoke exposure also increased pulse wave dP/dt in the absence of any structural modifications in the arterial wall. Furthermore, although nitric oxide production and endothelin-1 levels were not altered by secondhand tobacco smoke, there was increased inactivation of nitric oxide as indicated by peroxynitrite production. Increased lung neutrophils or pulmonary CYP1A1 may be responsible for the increase in oxidative stress in rats exposed to secondhand tobacco smoke. In turn, this may be related to the observed failure of blood pressure to dip during periods of sleep and a possible increase in arterial stiffness.

Circadian Patterns of Heart Rate and Cardiac Pressures in Patients with Heart Failure Using Continuous Hemodynamic Monitoring

Circadian Patterns of Heart Rate and Cardiac Pressures in Patients with Heart Failure Using Continuous Hemodynamic Monitoring

Cardiovascular function and circadian patterns in rats after area postrema lesions or prolonged food restriction

The role of the area postrema (AP) in baseline cardiovascular function was evaluated by radio telemetry in rats with lesions of AP (APX), along with the effect of APX on circadian patterns of cardiovascular function and ingestive behavior. Despite lesion-induced hypophagia and body weight loss, APX did not affect circadian patterns of mean arterial pressure (MAP), heart rate (HR), or ingestion but did cause a substantial decrease (−60 bpm) in resting HR. The bradycardia was not attributable to weight loss, as resting HR in weight-matched controls, though decreased from baseline, was significantly greater than that in rats with APX. In weight-matched controls, HR increased slightly when weight returned to baseline; however, the bradycardia persisted in rats with APX. These results suggest that AP contributes to resting HR, independent of weight loss or changes in circadian patterns of HR or MAP.

Ventricular repolarization is prolonged in nondipper hypertensive patients: role of left ventricular hypertrophy and autonomic dysfunction.

The aim of this study was to investigate the influence of circadian behavior of blood pressure, left ventricular hypertrophy, and autonomic function on QTc interval duration in untreated hypertensive patients. Hypertensive patients underwent simultaneous blood pressure and ECG 24-h ambulatory monitoring. Patients were classified into two groups on the basis of a lack of nocturnal fall in blood pressure, as dippers and nondippers. A group of normotensive healthy subjects was studied as controls. QT and QTc intervals were automatically computed and spectral analysis was applied to RR interval time series from the same electrocardiogram (ECG) recordings. Left ventricular mass index (LVMI) was computed by echocardiogram. No difference among the three groups was found concerning mean values and circadian pattern of heart rate; by contrast, QTc was significantly longer in nondippers compared to dippers or to normotensive subjects, particularly at night-time, whereas all groups exhibited similar circadian variations in heart rate. Compared to dippers, nondippers showed significantly higher LVMI, which positively correlated with QTc, and parasympathetic withdrawal, which negatively correlated with QTc. Nondippers show a prolonged ventricular repolarization throughout the 24-h period, absent either in dippers or normotensives. The association of left ventricular hypertrophy and vagal deactivation may lead to prolongation of QTc, potentially facilitating ventricular arrhythmias in nondipper hypertensive patients.

Altered circadian blood pressure profile in patients with active acromegaly. Relationship with left ventricular mass and hormonal values.

To determine the relationships between the circadian blood pressure profile and left ventricular mass, hormonal pattern and insulin sensitivity indices in patients with active acromegaly, ambulatory 24-h blood pressure monitoring (ABPM) was recorded in 25 subjects (47.0 +/- 15.1 years, range 23-72). Serum growth hormone (GH) and insulin-like growth factor-1, fasting and mean plasma glucose and insulin during oral glucose tolerance test (OGTT), insulinogenic index, the sum of the plasma insulin levels and the homeostasis model insulin resistance index (Homa's index) were determined. Left ventricular mass index (LVMI) was calculated from two-dimensional guided M-mode echocardiogram. The prevalence of hypertension was 56% (n = 14) and 40% (n = 10) according to sphygmomanometric measurements and ABPM, respectively. Non-dipping profile was observed in six of 10 hypertensives and in six of 15 normotensives. Serum growth hormone, fasting glucose, the area under the serum insulin curve and LVMI were higher for acromegalics with non-dipping profile than for dippers (all of them, P < 0.05). In non-dippers daytime heart rate was higher than night time (P < 0.001). In conclusion, the main observations in the present study suggested that both normotensive and hypertensive acromegalics had a highly prevalent non-dipping profile with a preserved circadian pattern of heart rate, that was associated with higher levels of serum GH. The disturbance in nocturnal blood fall in normotensives was associated with a decreased insulin sensitivity. The role of GH in blood pressure circadian rhythm regulation in essential hypertension deserves further studies.

Circadian heart rate changes and light-dependence in the Mediterranean seabream Sparus aurata

Despite the abundant literature on circadian heart rate rhythms in fish, few studies have attempted to elucidate if such pattern is endogenous or if it is modulated by environmental cues. In this study, heart rates were continuously recorded in Sparus aurata acclimated to different light regimes (normal or shifted LD 12:12 cycle and a pulsed 0.75:0.75 LD cycle) to investigate the endogenous nature and the role of light on the circadian pattern of heart rate. Under LD 12:12, the daily pattern of heart rate showed higher values at night and lower rates during the day (average amplitude of the heart rate change of 10.6 ± 5.7 beats min−1). The circadian pattern was maintained in animals under constant light but the amplitude was decreased (2.4 ± 1.1 beats min−1). Light masks the expression of the rhythm because under a pulsed LD cycle, heart rate tracks the pulsed LD phases, increasing during the dark phase and decreasing during the light phase. Besides the ultradian pattern imposed, an underlying circadian rhythm was detected, which indicates that the rhythm is endogenous. However, the strong link between heart rate and light obtained under pulsed LD cycles suggest the timing mechanism to be mostly based on external light reception.

The relationship between psychiatric illness and the circadian pattern of heart rate.

The aim of this study was to investigate the relationship between psychiatric status and the circadian pattern of heart rate. Serial 24-hour recordings of minute average heart rate were obtained from 30 normal volunteers and 200 patients representing a range of DSM-III-R diagnoses. Records were compared in terms of their circadian 'morphology' and grouped into different pattern types. The distribution of patterns in different diagnoses was analysed statistically. It was found that states such as generalised anxiety and depression are strongly associated with a distinctive circadian pattern, whereas others such as somatoform disorder show more variation in this regard. Serial recordings show that the relationship between psychiatric status and circadian pattern is state-dependent; a change in clinical status leads to a change in the circadian pattern. The presented findings together suggest that there is a systematic relationship between psychiatric status and heart rate in which core physiological differences between certain states are reflected in distinctively different circadian patterns of activity. The state-dependent nature of this relationship suggests obvious practical applications, and examples are given of how these adjunct data can provide objective indices of clinical status and change. At a theoretical level, the physiological dimension revealed by these data may help to define more reliable syndromal distinctions between various clinical manifestations and hence contribute to a more robust nosology.

Temporal patterns of heart rate and blood pressure in elders.

Circadian patterns of heart rate, systolic and diastolic blood pressure, and rate-pressure product were compared in elders with heart disease (N = 22, mean age 86 years) and a comparison group (N = 18, mean age 80 years) who did not have a cardiac diagnosis. For 4 consecutive days, automated measures of heart rate, diastolic and systolic blood pressure, and rate-pressure product were taken every 2 hours while subjects were awake. Activity-rest patterns were recorded by an observer, and demographic and medication profiles were obtained. Data were subjected to cosinor analysis, and the groups were compared on rhythmic parameters. Although the cardiac subjects were older, in poorer health, less active, and more prone to daytime napping, they exhibited more rhythms in rate-pressure product than did the comparison subjects. The cardiac group also had more synchronized oscillation of overt heart rate and systolic blood pressure rhythms. These results can be attributed to standardized times of cardiac medication administration. Attention to patterns of heart rate and systolic blood pressure in elders may suggest more appropriate times of day for conducting individual cardiac assessments.

993-45 Atrial Fibrillation: Sotalol's Heart Rate Reductions are Selective for Circadian Hours Where Heart Rate is High

We used 24-hour ambulatory ECG monitoring (AEM) to determine sotalol's circadian heart rate (HR) effects in chronic atrial fibrillation. Sixty subjects on a stable digoxin dosage had AEM after one week of single-blind placebo (PLC) and then again after 2 weeks of double-blind sotalol (80 or 160 mg qd) or continued PLC. Circadian HR patterns (average, high and low) for AEM's with = 18 paired hours (average = 23.2 hrs) were analyzed. Baseline and endpoint HR curves (open and closed symbols) are shown for sotalol and placebo groups. Circadian HR patterns on continued placebo were stable, but sotalol produced reductions in HR which were equal for the 80 and 160 mg doses. The largest HR reductions occurred between 11 am and 7 pm, where sympathetic tone is high - consistent with sotalol's beta blocking activity. Mean reductions in 24 hour high, average and low HR were 18 BPM, 11 bpm and 7 bpm, respectively, with the high and average HR reductions being significant (p &lt; 0.05). Sotalol's HR lowering effects in atrial fibrillation are selective for circadian hours when HR is high, having lesser effects on low HR values. The threshold for beta blocking activity is 80 mg qd, with no further lowering seen at 160 mg qd 2 .

Quality of life and circadian variation of heart rate and heart rate variability in short‐term survivors and nonsurvivors after acute myocardial infarction

The purpose of this study was the simultaneous examination of the quality of life and changes in heart rate (HR) variables of patients immediately following acute myocardial infarction (AMI). Quality of life, estimated on a rating scale assessing the patients' well-being, as well as the circadian rhythm of their HR and HR variability, were determined within the first 3 days and at approximately 3 weeks after admission and the results were related to survival. The quality of life within the first 3 days post AMI was low in both the surviving (n = 42) and the nonsurviving (n = 5) patients but only the scores of the survivors increased significantly over the following three weeks. The HR of the survivors, initially lower than that of the nonsurvivors, decreased significantly at 3 weeks and a normal circadian pattern had developed. The HR variability of the survivors within the first 3 days was significantly higher than that of the nonsurvivors and had developed a clear circadian pattern after 3 weeks. It is concluded that in patients with AMI such diverse clinical aspects as quality of life and circadian patterns of HR and HR variability can be assessed meaningfully immediately post AMI and may find common expression in changes in sympathovagal balance.

Circadian variation of heart rate is affected by environment: a study of continuous electrocardiographic monitoring in members of a symphony orchestra.

Twenty four hour ambulatory ST segment monitoring was performed on 48 members (43 players and five members of the management/technical team) of the British Broadcasting Corporation (BBC) symphony orchestra without a history of cardiac disease. This period included final rehearsals and live performances (for audience and radio) of music by Richard Strauss and Mozart at the Royal Festival Hall (n = 36) and Rachmaninov and Tchaikovsky at the Barbican Arts Centre (n = 21). During the period of monitoring one person (2%) had transient ST segment changes. Mean heart rates were significantly higher during the live performances than during the rehearsals. Mean heart rates during the live performance of Rachmaninov and Tchaikovsky were significantly higher than during Strauss and Mozart in those (n = 6) who were monitored on both occasions. Mean heart rates in the management and technical team were higher than those of the players. The recognised circadian pattern of heart rate, with a peak in the morning waking hours, was altered similarly during both concert days, with a primary peak occurring in the evening hours and a lesser peak in the morning for both musicians and management/technical staff. This study showed that environmental factors are of primary importance in defining the circadian pattern of heart rate. This has important implications when identifying peak periods of cardiovascular stress and tailoring drug treatment for patients with angina pectoris.

Circadian pattern of heart rate is altered by stress: A study of continuous electrocardiographic monitoring during strauss, mozart, rachmaninov and tchaikovsky

Circadian pattern of heart rate is altered by stress: A study of continuous electrocardiographic monitoring during strauss, mozart, rachmaninov and tchaikovsky