Acute Sleep Deprivation is Associated with Increased QT Dispersion in Healthy Young Adults

Sex difference in cardiac performance in individuals with irregular shift work

Background: sex differences existed in animal behavioral adaption and activity rhythms when exposed to chronic disruption of the circadian rhythm. Whether these differences extend to cardiac performance has not been fully investigated by cardiac imaging technology.

Methods

One hundred and thirty patients enrolled in this study. Patients were divided into the day shift (DS) group and the irregular shift (IRS) group based on whether involved in the night shift and the frequency of the night shift. Comparisons of clinical data and cardiac imaging parameters were performed to identify the sex difference in cardiac function in the participants with day shift work or irregular shifts.

Results

The absolute value of GLS was significantly lower in male IRS group than in male DS group. In females, no significant difference was tested in left ventricular function between the two groups. In male participants, Weekly work hours (WWH) was positively correlated with HR (r = 0.51, p = 0.02) and QTc duration (r = 0.68, p < 0.00), and weakly negatively correlated with the GLS (r = -0.38, p = 0.05). Amongst patients, there was a 2.67-fold higher relative risk (RR) for impaired GLS in males than in females, with a 95 % confidence interval (CI) of 1.20-5.61. Moreover, there was an increased risk in the male IRS group compared to the female IRS group to develop impaired GLS (RR:3.14, 95 % CI 1.20-7.84).

Conclusions

The present study suggests that chronic circadian disruption brings cardiac dysfunction in people with night-shift work. Gender differences exist in the impact of circadian rhythmicity on cardiac function and may help to guide the work schedule and breaks in shift workers and bring forward prevention strategies in response to chronic circadian disruption.

Sudden gamer death: non-violent death cases linked to playing video games

BACKGROUND AND AIMS

Internet gaming disorder (IGD) is an emerging problem. Rarely, media reports about people, who have died during playing video games, but thus far no systematic, scientific study is available about the topic. We investigated such cases, looking for common characteristics, connection between gaming and death, and the possible reasons leading to death.

METHODS

Cases were collected through internet search with general keywords, with ones specific to identified cases, and by working along cross references.

RESULTS

24 cases were found: one from 1982, the others between 2002 and 2021. Twenty-three of the victims were male, age ranged from 11 to 40 years. More than half of the cases originated from Southeast Asia, and 12 deaths happened in internet cafes. Gamers played action-rich multiplayer games. In 18 cases the gaming session before death was extremely long (around a day or even several days) with minimal rest. The cause of death was pulmonary embolism in 5 cases, cerebral hemorrhage in 2 cases, most of the rest was presumably due to fatal cardiac arrhythmia.

DISCUSSION

Long sedentary position and dehydration may precipitate thromboembolism, acute blood pressure elevation during gaming may promote cerebral hemorrhage, and several factors (including acute and chronic sleep deprivation, exhaustion, stress) can lead to acute autonomic dysfunction and fatal arrhythmia.

CONCLUSION

Incidence of non-violent death cases linked to playing video games is presumably very low. It mostly occurs in young males and it is often characterized by extremely long gaming time.

Atrial Fibrillation's Influence on Short Sleep Duration Increases the Risk of Fatness in Management Executives

This study explored whether atrial fibrillation (AF)’s influence on short sleep duration (SD) increases the subsequent risk of fatness in management executives. This study included 25,953 healthy individuals working as management executives with ages ranging from 35 to 65 years (19,100 men and 6853 women) who participated in a qualifying physical filter program from 2006 to 2017 in Taiwan. Men and women who slept < 4 h had a 4.35-fold and 5.26-fold higher risk of developing AF than those who slept 7−8 h normally. Men and women who slept < 4 h had a 6.44-fold and 9.62-fold higher risk of fatness than those who slept 7−8 h. Men and women with AF had a 4.52-fold and 6.25-fold higher risk of fatness than those without AF. It showed that AF induced by short SD increases the risk of fatness. A short SD can predict an increased risk of fatness among management executives in Taiwan.

Sleep duration and atrial fibrillation risk in the context of predictive, preventive, and personalized medicine: the Suita Study and meta-analysis of prospective cohort studies

Background

Short and long sleep durations are common behaviors that could predict several cardiovascular diseases. However, the association between sleep duration and atrial fibrillation (AF) risk is not well-established. AF is preventable, and risk prevention approaches could reduce its occurrence. Investigating whether sleep duration could predict AF incidence for possible preventive interventions and determining the impact of various lifestyle and clinical characteristics on this association to personalize such interventions are essential. Herein, we investigated the association between sleep duration and AF risk using a prospective cohort study and a meta-analysis of epidemiological evidence.

Methods

Data of 6898 people, aged 30-84 years, from the Suita Study, were analyzed. AF was diagnosed during the follow-up by ECG, medical records, checkups, and death certificates, while a baseline questionnaire was used to assess sleep duration. The Cox regression was used to compute the hazard ratios (HRs) and 95% confidence intervals (CIs) of AF risk for daily sleep ≤ 6 (short sleep), ≥ 8 (long sleep), and irregular sleep, including night-shift work compared with 7 h (moderate sleep). Then, we combined our results with those from other eligible prospective cohort studies in two meta-analyses for the short and long sleep.

Results

In the Suita Study, within a median follow-up period of 14.5 years, short and irregular sleep, but not long sleep, were associated with the increased risk of AF in the age- and sex-adjusted models: HRs (95% CIs) = 1.36 (1.03, 1.80) and 1.62 (1.16, 2.26) and the multivariable-adjusted models: HRs (95% CIs) = 1.34 (1.01, 1.77) and 1.63 (1.16, 2.30), respectively. The significant associations between short and irregular sleep and AF risk remained consistent across different ages, sex, smoking, and drinking groups. However, they were attenuated among overweight and hypertensive participants. In the meta-analyses, short and long sleep durations were associated with AF risk: pooled HRs (95% CIs) = 1.21 (1.02, 1.42) and 1.18 (1.03, 1.35). No signs of significant heterogeneity across studies or publication bias were detected.

Conclusion

Short, long, and irregular sleep could be associated with increased AF risk. In the context of predictive, preventive, and personalized medicine, sleep duration should be considered in future AF risk scores to stratify the general population for potential personalized lifestyle modification interventions. Sleep management services should be considered for AF risk prevention, and these services should be individualized according to clinical characteristics and lifestyle factors.

Graphical abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s13167-022-00275-4.

How spaceflight challenges human cardiovascular health

The harsh environmental conditions in space, particularly weightlessness and radiation exposure, can negatively affect cardiovascular function and structure. In the future, preventive cardiology will be crucial in enabling safe space travel. Indeed, future space missions destined to the Moon and from there to Mars will create new challenges to cardiovascular health while limiting medical management. Moreover, commercial spaceflight evolves rapidly such that older persons with cardiovascular risk factors will be exposed to space conditions. This review provides an overview on studies conducted in space and in terrestrial models, particularly head-down bedrest studies. These studies showed that weightlessness elicits a fluid shift towards the head, which likely predisposes to the spaceflight-associated neuro-ocular syndrome, neck vein thrombosis, and orthostatic intolerance after return to Earth. Moreover, cardiovascular unloading produces cardiopulmonary deconditioning which may be associated with cardiac atrophy. In addition to limiting physical performance, the mechanism further worsens orthostatic tolerance after return to Earth. Finally, space conditions may directly affect vascular health, however, the clinical relevance of these findings in terms of morbidity and mortality is unknown. Targeted preventive measures, which are referred to as countermeasures in aerospace medicine, and technologies to identify vascular risks early on will be required to maintain cardiovascular performance and health during future space missions.

Cardiovascular Complications of Sleep Disorders: A Better Night's Sleep for a Healthier Heart / From Bench to Bedside

Sleep is essential to and an integral part of life and when lacking or disrupted, a multitude of mental and physical pathologies ensue, including cardiovascular (CV) disease, which increases health care costs. Several prospective studies and meta-analyses show that insomnia, short (<7h) or long (>9h) sleep and other sleep disorders are associated with an increased risk of hypertension, metabolic syndrome, myocardial infarction, heart failure, arrhythmias, CV disease risk and/or mortality. The mechanisms by which insomnia and other sleep disorders lead to increased CV risk may encompass inflammatory, immunological, neuro-autonomic, endocrinological, genetic and microbiome perturbations. Guidelines are emerging that recommend a target of >7 h of sleep for all adults >18 years for optimal CV health. Treatment of sleep disorders includes cognitive-behavioral therapy considered the mainstay of non-pharmacologic management of chronic insomnia, and drug treatment with benzodiazepine receptor agonists binding to gamma aminobutyric acid type A (benzodiazepine and non-benzodiazepine agents) and some antidepressants. However, observational studies and meta-analyses indicate an increased mortality risk of anxiolytics and hypnotics, although bias may be involved due to confounding and high heterogeneity in these studies. Nevertheless, it seems that the risk incurred by the non-benzodiazepine hypnotic agents (Z drugs) may be relatively less than the risk of anxiolytics, with evidence indicating that at least one of these agents, zolpidem, may even confer a lower risk of mortality in adjusted models. All these issues are herein reviewed.

Effects of Sleep Duration on Cardiovascular Events

PURPOSE OF REVIEW

Sleep is an essential component of human health, and suboptimal sleep duration has been associated with increased cardiovascular morbidity and mortality. This review summarizes physiological and pathological effects of sleep duration on the cardiovascular system.

RECENT FINDINGS

Both decreased and increased duration of sleep lead to increased cardiovascular mortality and has a U-shaped curve. Sleep apnea is an independent risk factor for atherosclerosis and hypertension, and its treatment with continuous positive airway pressure (CPAP) results in increased survival. Estimated sleep duration of 6-8 h is associated with decreased mortality and major cardiovascular events and should be addressed by clinicians during routine visits.

Sleep Duration and Risk of Atrial Fibrillation: a Systematic Review

Background

Little is known about a possible association between sleep duration and the incidence of atrial fibrillation (AF), in healthy people. In this systematic review, we conducted a literature search to examine possible association between sleep duration and the incidence of AF.

Methods

Scientific databases (PubMed, Web of Knowledge and Embase) were searched using relevant Medical Subject Headings and keywords, to retrieve studies written in English and published until November 2017. Only observational studies were included. Since sleep duration categories were not consistent, it was feasible to run a meta-analysis.

Results

Six eligible studies were included. Long sleep duration (≥ 8 hours) was found to be associated with an increased risk of AF (adjusted hazard ratio (aHR) = 1.13; 95% CI: 1.00-1.27 and aHR= 1.5, 95% CI: 1.07-2.10) in two studies. One study reported that sleep duration less than 6 hours was associated with an increased risk of AF (aHR= 1.58, 95% CI: 1.18 -2.13) compared to sleeping for 6-7 hours. In two studies, mean sleep duration was lower in AF groups compared to the non-AF group. Insomnia was associated with an increased risk of AF in another study (aHR= 1.33, 95% CI: 1.25-1.41).

Conclusions

Unhealthy sleep duration, defined as either less than 6 hours or more than 8 hours, may be associated with an increased risk of AF.

Sinoatrial node remodels in chronic sleep-restricted rats

Chronic Sleep Restriction (CSR) is known as a risk factor for cardiovascular diseases. However, the structural changes of Sinoatrial (SA) node cells have received less attention. This study aimed to evaluate the effects of CSR on SA node in an animal model using stereological methods. Adult male Sprague-Dawley rats were randomly divided into CSR, grid-floor, and control groups. The CSR procedure was designed such a way that the animals had a full cycle of sleep (6 hours) per day, while they were unable to have a Rapid Eye Movement (REM) sleep during the remaining 18 hours. This was induced by a multiplatform box containing water. The grid-floor animals were placed in the same multiplatform box with a grid-floor covering to prevent falling in water. After 21 days, the right atria were dissected out. Then, the location of the SA node was determined and evaluated by stereological techniques. The total volume of the SA node, the total volume of the main node cells, the volume of the connective tissue, and mean volume of the node cells were respectively enlarged by 60%, 47%, 68%, and 51% in the CSR animals compared to the grid-floor rats (p < 0.05). However, no significant changes were detected in these parameters in the control and grid-floor animals. The population of the main node cells remained constant in all animal groups. In addition, the three-dimensional reconstruction of the SA node in the CSR group showed a hypertrophied appearance. In conclusion, CSR induced hypertrophic changes in the rats' SA node structures without alteration in the number of main node cells.

Association between insomnia and atrial fibrillation in a Chinese population: A cross-sectional study

BACKGROUND

Insomnia is the most prevalent sleep disorder; however, little research has explored the link between insomnia and atrial fibrillation (AF).

HYPOTHESIS

Insomnia is associated with increased risk of AF in a Chinese population.

METHODS

A total of 8371 Chinese participants (4314 males; mean age, 42.4 ± 13.1 years) were enrolled in this cross-sectional study to investigate the association between insomnia and AF. AF was assessed in a standard supine resting position with a 10-s 12-lead electrocardiograph (ECG) or by self-reported history. Insomnia was assessed using the Athens Insomnia Scale (AIS), and a score of ≥6 was regarded as having insomnia. The association between insomnia and AF was determined by logistic regression analysis.

RESULTS

Among the 8371 subjects, 1074 (12.8%) had different degrees of insomnia, and AF was observed in 50 subjects (0.60%). After adjusting for potential confounders, individuals with insomnia had moderately increased likelihood of suffering from AF compared with those without insomnia (odds ratio [OR]: 1.92, 95% confidence interval [CI]: 1.00-3.70, P = 0.05). After stratifying data by age, a significant positive association was found in those age <40 years (OR: 6.52, 95% CI: 1.64-25.83, P = 0.01), and a similar trend existed in males after stratifying by sex, although this relationship was not statistically significant (OR: 2.11, 95% CI: 0.92-4.83, P = 0.08).

CONCLUSIONS

Individuals with insomnia may have a higher risk of AF in the particular Chinese population assessed in this study. Age (<40 years) is a significant factor in the association between insomnia and AF.

Sleep Disruption is Associated with Increased Ventricular Ectopy and Cardiac Arrest in Hospitalized Adults

STUDY OBJECTIVES

To determine whether sleep disruption increases ventricular ectopy and the risk of cardiac arrest in hospitalized patients.

METHODS

Hospital emergency codes (HEC) trigger multiple hospital-wide overhead announcements. In 2014 an electronic "code white" program was instituted to protect staff from violent patients. This resulted in an increase in nocturnal HEC. Telemetry data was examined between September 14 and October 2, 2014. The frequency of nocturnal announcements was correlated with changes in frequency of premature ventricular complexes per hour (PVC/h). Cardiac arrest data were examined over a 3-y period. All HEC were assumed to have triggered announcements. The relationship between nocturnal HEC and the incidence of subsequent cardiac arrest was examined.

RESULTS

2,603 hours of telemetry were analyzed in 87 patients. During nights with two or fewer announcements, PVC/h decreased 33% and remained 30% lower the next day. On nights with four or more announcements, PVC/h increased 23% (P < 0.001) and further increased 85% the next day (P = 0.001). In 2014, following the introduction of the code white program, the frequency of all HEC increased from 1.1/day to 6.2/day (P < 0.05). The frequency of cardiac arrest/24 h rose from 0.46/day in 2012-2013 to 0.62/day in 2014 (P = 0.001). During daytime hours (06:00-22:00), from 2012 through 2014, the frequency of cardiac arrest following zero, one or at least two nocturnal HEC were 0.331 ± 0.03, 0.396 ± 0.04 and 0.471 ± 0.09 respectively (R(2) = 0.99, P = 0.03).

CONCLUSIONS

Sleep disruption is associated with increased ventricular ectopy and increased frequency of cardiac arrest.

Sleep Duration and Cardiovascular Disease Risk: Epidemiologic and Experimental Evidence

Inadequate sleep is increasingly pervasive, and the impact on health remains to be fully understood. The cardiovascular consequences alone appear to be substantial. This review summarizes epidemiologic evidence regarding the association between extremes of sleep duration and the prevalence and incidence of cardiovascular diseases. The adverse effects of experimental sleep loss on physiological functions are discussed, along with cardiovascular risk factors that may underlie the association with increased morbidity and mortality. Current data support the concept that inadequate sleep duration confers heightened cardiovascular risk. Thus implementation of preventative strategies may reduce the potential disease burden associated with this high-risk behavior.

Obstructive Sleep Apnea in Patients with Congenital Long QT Syndrome: Implications for Increased Risk of Sudden Cardiac Death

BACKGROUND

Congenital long QT syndrome (LQTS) is a familial arrhythmogenic cardiac channelopathy characterized by prolonged ventricular repolarization and increased risk of torsades de pointes-mediated syncope, seizures, and sudden cardiac death (SCD). QT prolongation corrected for heart rate (QTc) is an important diagnostic and prognostic feature in LQTS. Obstructive sleep apnea (OSA) has been increasingly implicated in the pathogenesis of cardiovascular disease, including arrhythmias and SCD. We tested the hypothesis that the presence of concomitant OSA in patients with LQTS is associated with increased QT intervals, both during sleep and while awake.

METHODS AND RESULTS

Polysomnography with simultaneous overnight 12-lead electrocardiography (ECG) was recorded in 54 patients with congenital LQTS and 67 control subjects. OSA was diagnosed as apnea-hypopnea index (AHI) ≥ 5 events/h for adults and AHI > 1 event/h for children. RR and QT intervals were measured from the 12-lead surface ECG. QTc was determined by the Bazett formula. Respiratory disturbance index, AHI, and arousal index were significantly increased in patients with LQTS and with OSA compared to those without OSA and control subjects. QTc during different sleep stages and while awake was also significantly increased in patients with LQTS and OSA compared to those without OSA. Severity of OSA in patients with LQTS was directly associated with the degree of QTc.

CONCLUSIONS

The presence and severity of obstructive sleep apnea (OSA) in patients with congenital long QT syndrome (LQTS) is associated with increased QT prolongation corrected for heart rate, which is an important biomarker of sudden cardiac death (SCD). Treatment of OSA in LQTS patients may reduce QT prolongation, thus reducing the risk of LQT-triggered SCD.

Effect of acute sleep deprivation on left atrial mechanics assessed by three-dimensional echocardiography

BACKGROUND

Although sleep deprivation (SD) affects cardiovascular system in many ways, physio-pathological changes in cardiac chamber volume and function have not been described well. The aim of the present study was to investigate the effect of SD on left atrial (LA) and ventricular function with three-dimensional (3D) echocardiography.

METHODS

Thirty-two healthy individuals (12 females, mean age 33.25 ± 8.18) were evaluated. Echocardiographic examination was performed once after a night of regular sleep and a night of sleep debt. Beside conventional parameters, 3D phasic volumes and function were measured using a commercially available 3D echocardiography system and offline analysis software.

RESULTS

Mean sleep duration of the study group was 8.15 ± 2.19 h in the day of regular sleep and 2.56 ± 2.25 h in the day of sleep deprivation. There was a significant prolongation in deceleration time (180.83 ± 15.34 vs. 166.44 ± 26.12; p = 0.044) and increase in E/e' (6.95 ± 1.26 vs. 6.38 ± 0.85; p = 0.005). Among 3D measurements, the difference in left ventricular ejection fraction (EF), LA EF, LA reservoir function and LA active EF were not significant. Mean LA passive EF of the individuals was significantly lower after night shift (24.10 ± 7.66 vs. 31.49 ± 7.75; p = 0.006).

CONCLUSION

Acute SD is associated with a reduction in LA passive emptying function in healthy adults. 3D-derived indices were sufficient to show subclinical diastolic dysfunction according to impairment in passive phase of LA ejection. Prospective large-scale studies are needed to enlighten this issue.

Effects of sleep deprivation on action potential and transient outward potassium current in ventricular myocytes in rats

BACKGROUND

Sleep deprivation contributes to the development and recurrence of ventricular arrhythmias. However, the electrophysiological changes in ventricular myocytes in sleep deprivation are still unknown.

MATERIAL AND METHODS

Sleep deprivation was induced by modified multiple platform technique. Fifty rats were assigned to control and sleep deprivation 1, 3, 5, and 7 days groups, and single ventricular myocytes were enzymatically dissociated from rat hearts. Action potential duration (APD) and transient outward current (Ito) were recorded using whole-cell patch clamp technique.

RESULTS

Compared with the control group, the phases of APD of ventricular myocytes in 3, 5, and 7 days groups were prolonged and APD at 20% and 50% level of repolarization (APD20 and APD50) was significantly elongated (The APD20 values of control, 1, 3, 5, and 7 days groups: 5.66±0.16 ms, 5.77±0.20 ms, 8.28±0.30 ms, 11.56±0.32 ms, 13.24±0.56 ms. The APD50 values: 50.66±2.16 ms, 52.77±3.20 ms, 65.28±5.30 ms, 83.56±7.32 ms, 89.24±5.56 ms. P<0.01, n=18). The current densities of Ito significantly decreased. The current density-voltage (I-V) curve of Ito was vitally suppressed downward. The steady-state inactivation curve and steady-state activation curve of Ito were shifted to left and right, respectively, in sleep deprivation rats. The inactivation recovery time of Ito was markedly retarded and the time of closed-state inactivation was markedly accelerated in 3, 5, and 7 days groups.

CONCLUSIONS

APD of ventricular myocytes in sleep deprivation rats was significantly prolonged, which could be attributed to decreased activation and accelerated inactivation of Ito.

Negative effects of acute sleep deprivation on left ventricular functions and cardiac repolarization in healthy young adults

BACKGROUND

Sleep deprivation (SD) is associated with an increased incidence of adverse cardiovascular events, we aimed to determine the impact of acute SD on structural and functional alterations of the left ventricle (LV) and on electrocardiogram (ECG) markers including T wave peak-to-end interval (TpTe), QT interval, and TpTe/QT ratio in healthy subjects after a night of SD.

METHODS

The study population consisted of 40 healthy young adults (19 males, 21 females; mean age: 28.2 ± 3.86 years). Echocardiographic images and ECGs were obtained from the participants after a night of regular sleep (RS) and SD. The average sleep time of the subjects was 6.67 ± 1.76 hours during RS and 1.25 ± 0.74 hours during a night of SD.

RESULTS

The myocardial performance index, isovolumic relaxation time, and deceleration time values were significantly higher after SD. In addition, the corrected TpTe interval, corrected QT interval (QTc) max, and TpTe/QT ratio were significantly increased after a night of SD when compared with a night of RS (78.5 ± 6.8 ms vs 70.7 ± 7.6 ms, P < 0.001; 407.5 ± 18.6 ms vs 395.07 ± 21.3 ms, P = 0.001; and 0.189 ± 0.014 ms vs 0. 0.179 ± 0.016 ms, P < 0.001, respectively). However, subjects had similar QTp interval values (defined as beginning of the QRS complex to peak of the T wave) after a night of SD as a night of RS (294.6 ± 19.0 vs 291.9 ± 18.5, P = 233).

CONCLUSION

Our crossover study revealed the presence of subclinical LV diastolic functional changes and increased QT intervals, TpTe intervals, and TpTe/QT ratios in healthy young adults after one night SD. Therefore, the increased QT interval occurred secondary to the increased TpTe interval in this population.

The effects of sleep deprivation on microRNA expression in rats submitted to pilocarpine-induced status epilepticus

Epilepsy is a neurological disorder with significant prevalence and the individuals affected by this disease have a great probability of occurrence of a lethal phenomenon known as Sudden Unexpected Death in Epilepsy (SUDEP). SUDEP occurs mainly during the night and probably during sleep. The pathophysiological mechanisms involved in this lethal phenomenon are still obscure and new evidences that could corroborate in this area are warranted. Thus, the aim of the present study was to evaluate the effect of sleep deprivation in the expression of microRNA (miRNA) in the frontal cortex and heart tissues of adult male rats after 50days of saline (SAL) or pilocarpine-induced status epilepticus (PILO). Initially 389 miRNA expressions were evaluated between SAL and PILO groups by microarray. Subsequently, 3 differentially expressed miRNAs of each tissue were investigated after total sleep deprivation (TSD 6h) and paradoxical sleep deprivation (PSD 24h). Still, it was analyzed that the effects of sleep rebound with equivalent duration of PSD and TSD. There was a significant increase of miR-146a expression, an important inflammatory modulator in the frontal cortex of PILO rats when compared to SAL animals. Animals treated with pilocarpine were affected by TSD (through overexpression of miRNAs related to inflammatory process) and these changes were maintained even after a sleep window of 6h. In contrast, miRNAs associated with heart diseases were down-regulated in PSD rebound, suggesting a possible restoration of homeostasis in cardiovascular system of SAL and PILO groups.