Acute sleep deprivation is associated with increased electrocardiographic P-wave dispersion in healthy young men and women

Insomnia and Cardiovascular Health: Exploring the Link Between Sleep Disorders and Cardiac Arrhythmias

Cardiovascular diseases (CVDs), driven by modern lifestyles, have increased, with atrial fibrillation (AF) being a major concern linked to heart failure and stroke. Insomnia affects a large population, especially younger individuals, males, and menopausal women, decreasing the quality of life and potentially causing autonomic disturbances and cardiac arrhythmias. PURPOSE OF REVIEW: This review explores the link between insomnia and cardiac arrhythmias, particularly AF, and its impact on cardiovascular health and emphasizes the need to address insomnia in individuals with cardiac arrhythmias by tailored strategies for sleep management to improve their overall well-being. RECENT FINDINGS: Recent findings emphasize maintaining a regular sleep schedule to lower AF and bradyarrhythmia risks. Better sleep scores correlate with reduced AF and bradyarrhythmia risks, while insomnia increases AF risk, particularly in those under 40 years of age. Studies underscore the potential impact of sleep management in reducing cardiovascular risks and highlight the importance of addressing sleep issues to improve cardiovascular health outcomes. Our review presents compelling evidence connecting insomnia and AF. Improving sleep patterns and addressing sleep issues can reduce AF risk, benefiting cardiovascular health. A comprehensive approach for managing at-risk individuals with cardiac arrhythmias, considering co-existing conditions, can decrease long-term disease burden and expenses. Incorporating sleep assessments and interventions into cardiovascular risk management, especially for those with insomnia, is recommended. Further research is needed to fully comprehend the complex relationship between insomnia and cardiac arrhythmias.

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.

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.

Relationship between Sleep Duration and Risk Factors for Stroke

Stroke is a leading cause of death and disability worldwide. While various risk factors have been identified, sleep has only been considered a risk factor more recently. Various epidemiologic studies have associated stroke with sleep such as sleep duration, and laboratory and clinical studies have proposed various underlying mechanisms. The pathophysiology is multifactorial, especially considering sleep affects many common risk factors for stroke. This review aims to provide an outline of the effect of sleep duration on common stroke risk factors. Appropriate sleep duration, especially in patients who have stroke risk factors, and increasing awareness and screening for sleep quality may contribute to primary prevention of stroke.

Long Sleep Duration Is an Independent Risk Factor for Incident Atrial Fibrillation in a Chinese Population: A Prospective Cohort Study

There is limited information on the relation between sleep duration and incident atrial fibrillation. We aimed to investigate this association in a Chinese population using cohort data from a study in Kailuan. The analysis included 87,693 participants (age range, 18–98 years) free of atrial fibrillation at the baseline survey. Participants were divided into three categories according to self-reported sleep duration: ≤6.0 hours, 7 hours (ref), ≥8.0 hours. Atrial fibrillation diagnosis was made on a standard 12-lead electrocardiogram and via self-reported history. Cox proportional hazards models were used to calculate hazard ratio (HR) and confidence interval (CI) for atrial fibrillation, according to sleep duration. During median follow-up of 7.89 (range, 6.36–8.57) years, 322 cases of atrial fibrillation had occurred. Using 7 hours of sleep as the reference group, multivariable adjusted HRs (95% CI) for atrial fibrillation were 1.07 (0.75–1.53), 1.0 (ref), and 1.50 (1.07–2.10), from lowest to highest category of sleep duration. Secondary analysis showed no evidence of interactions between sleep duration and sex and snoring on the risk of incident atrial fibrillation (p = 0.75/0.25). We conclude long sleep duration may be a potential predictor/marker for incident atrial fibrillation.

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.

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.

P-wave duration changes and dispersion in preeclampsia

OBJECTIVE

The purpose of this research was to study P wave parameters to determine the association between preeclampsia and future cardiovascular risk and to study the possible correlation between P waves and severity of preeclampsia.

STUDY DESIGN

In this case-control study 58 pregnant women with preeclampsia and 30 normal pregnant women were compared by measuring maximum and minimum P-wave durations and P-wave dispersion (Pd) in the late third trimester.

RESULTS

Minimum P wave values were lower and Pd values were higher, both significantly, in the preeclampsia groups than in the control group. In addition, the Pd values of the severe preeclampsia group were higher compared to that of the mild preeclampsia group.

CONCLUSION

Preeclampsia predisposes the patient to future cardiovascular complications including atrial or ventricular arrhythmias, but validated tools to assess the risks are yet not available. P-wave duration and Pd constitute a recent contribution to the field of noninvasive electrocardiology. Our data clearly demonstrated that minimum P wave and Pd values were significantly altered in preeclamptic pregnant women when compared to the controls. This important association can be used to screen women for increased risk in order to better target counseling regardinglifestyle modifications and to follow up and manage women with a history of preeclampsia more closely.

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.

[P wave dispersion increased in childhood depending on blood pressure, weight, height, and cardiac structure and function]

INTRODUCTION

Increased P wave dispersion are identified as a predictor of atrial fibrillation. There are associations between hypertension, P wave dispersion, constitutional and echocardiographic variables. These relationships have been scarcely studied in pediatrics.

OBJECTIVE

The aim of this study was to determine the relationship between P wave dispersion, blood pressure, echocardiographic and constitutional variables, and determine the most influential variables on P wave dispersion increases in pediatrics.

METHOD

In the frame of the PROCDEC II project, children from 8 to 11 years old, without known heart conditions were studied. Arterial blood pressure was measured in all the children; a 12-lead surface electrocardiogram and an echocardiogram were done as well.

RESULTS

Left ventricular mass index mean values for normotensive (25.91±5.96g/m(2.7)) and hypertensive (30.34±8.48g/m(2.7)) showed significant differences P=.000. When we add prehypertensive and hypertensive there are 50.38% with normal left ventricular mass index and P wave dispersion was increased versus 13.36% of normotensive. Multiple regression demonstrated that the mean blood pressure, duration of A wave of mitral inflow, weight and height have a value of r=0.88 as related to P wave dispersion.

CONCLUSIONS

P wave dispersion is increased in pre- and hypertensive children compared to normotensive. There are pre- and hypertensive patients with normal left ventricular mass index and increased P wave dispersion. Mean arterial pressure, duration of the A wave of mitral inflow, weight and height are the variables with the highest influence on increased P wave dispersion.

Effects of lying position on P-wave dispersion in patients with heart failure

OBJECTIVE

It was the aim of this study to investigate the effects of the right lateral decubitus, left lateral decubitus and supine lying position on P-wave dispersion (PWD) in patients with heart failure (HF).

SUBJECTS AND METHODS

Seventeen patients with HF whose ejection fraction was <35% were included in the study. Right lateral decubitus, left lateral decubitus and supine electrocardiogram (ECG) recordings were obtained. The recordings for each of the three positions were taken after the patients had maintained each position for 30 min to ensure a stabilized hemodynamic position. For the baseline recording, in supine position, there was no 30-min waiting period before the ECG.

RESULTS

After the right lateral decubitus position, there was a statistically significant reduction in the longest P-wave duration (100.0 ± 14.5 and 84.7 ± 16.2 ms; p = 0.001) and a significant decrease in PWD (41.7 ± 8.0 and 24.1 ± 7.1 ms; p < 0.0001). After the left lateral decubitus position, there was no significant change between the baseline PWD values (41.7 ± 8.0 and 40.2 ± 9.7 ms; p = 0.606). After the supine position, there was no significant change between the baseline PWD values (41.7 ± 8.0 and 39.7 ± 9.4 ms; p = 0.427).

CONCLUSION

Our study revealed that patients' PWDs and maximum P-wave durations were lower in the right lateral decubitus lying position than in other positions. The clinical implication of this study needs to be further explored.

One night on-call: sleep deprivation affects cardiac autonomic control and inflammation in physicians

BACKGROUND

Sleep loss is associated with increased cardiovascular morbidity and mortality. It is known that chronic sleep restriction affects autonomic cardiovascular control and inflammatory response. However, scanty data are available on the effects of acute sleep deprivation (ASD) due to night shifts on the cardiovascular system and its capability to respond to stressor stimuli. The aim of our study was to investigate whether a real life model of ASD, such as "one night on-call", might alter the autonomic dynamic response to orthostatic challenge and modify the immune response in young physicians.

METHODS

Fifteen healthy residents in Internal Medicine were studied before and after one night on-call at Rest and during a gravitational stimulus (head up-tilt test, HUT). Heart rate variability (HRV), blood pressure variability (BPV) and baroreflex sensitivity (BRS) were analyzed during Rest and HUT before and after ASD. Plasmatic hormones (epinephrine, norepinephrine, cortisol, renin, aldosterone, ACTH) and tissue inflammatory cytokines were measured at baseline and after ASD.

RESULT

HRV analysis revealed a predominant sympathetic modulation and a parasympathetic withdrawal after ASD. During HUT, the sympathovagal balance shifted towards a sympathetic predominance before and after ASD. However, the magnitude of the autonomic response was lower after ASD. BPV and BRS remained unchanged before and after ASD as the hormone levels, while IFN-γ increased after ASD compared to baseline.

CONCLUSION

In summary, one night of sleep deprivation, at least in this real-life model, seems to affect cardiovascular autonomic response and immune modulation, independently by the activation of the hypothalamic-pituitary axis.

How valuable is P-wave dispersion in the determination of carboxyhemoglobin levels?

Objective:

To determine whether or not wave/interval dispersions in electrocardiography (ECG) are increased, and to define whether wave and interval dispersions are correlated with carboxyhemoglobin (COHb) levels.

Methods:

ECG, complete blood count, and biochemical parameters were taken from 87 patients with carbon monoxide (CO) poisoning as well as 90 control patients with similar age, gender, and body mass index distribution. COHb levels were recorded in CO-poisoning patients. The COHb levels and the relationships with ECG parameters were studied.

Results:

Pmax, Pmin, Pd, PRmax, PRmin, PRd, QTmax, QTmin, QTd, cQTmax, cQTmin, cQTd, Tmax, Tmin, and Td in ECG were higher in intoxicated patients than the control group ( p < 0.05 for all). Pearson’s correlation analyses showed moderately significant positive correlations between COHb level and Pmax ( r = 0.224; p = 0.037) and Pd ( r = 0.222; p = 0.039). The receiver–operator characteristic (ROC) curve showed that a Pd value of 38 ms determined by ECG separates patients with a COHb ≥ 20% with area under the ROC curve of 0.78 (95%CI = 0.71–0.83), a sensitivity of 67.9% (95%CI = 59.4–75.6), a specificity of 95% (95%CI = 83.0–99.2], a positive predictive value of 97.9% (95%CI = 92.5–99.7), and a negative predictive value of 46.3% (95%CI = 35.3–57.7.)

Conclusion:

A significant increase in wave/interval dispersions in the ECG of CO-poisoning patients compared with controls may show that not only a part is affected but both atrium and the ventricles as a whole are affected by hypoxic ischemia. When COHb levels of the patients are unavailable, P dispersion on ECG may show CO poisoning level of the patient.

Sleep duration and risk of atrial fibrillation (from the Physicians' Health Study)

Although sleep quality and duration have been related to cardiovascular end points, little is known about the association between sleep duration and incident atrial fibrillation (AF). Hence, we prospectively examined the association between sleep duration and incident AF in a cohort of 18,755 United States male physicians. Self-reported sleep duration was ascertained during a 2002 annual follow-up questionnaire. Incident AF was ascertained through annual follow-up questionnaires. Cox regression analysis was used to estimate the relative risks of AF. The average age at baseline was 67.7 ± 8.6 years. During a mean follow-up of 6.9 ± 2.1 years, 1,468 cases of AF occurred. Using 7 hours of sleep as the reference group, the multivariate adjusted hazard ratio for AF was 1.06 (95% confidence interval 0.92 to 1.22), 1.0 (reference), and 1.13 (95% confidence interval 1.00 to 1.27) from the lowest to greatest category of sleep duration (p for trend = 0.26), respectively. In a secondary analysis, no evidence was seen of effect modification by adiposity (p for interaction = 0.69); however, prevalent sleep apnea modified the relation of sleep duration with AF (p for interaction = 0.01). From the greatest to the lowest category of sleep duration, the multivariate-adjusted hazard ratio for AF was 2.26 (95% confidence interval 1.26 to 4.05), 1.0 (reference), and 1.34 (95% confidence interval 0.73 to 2.46) for those with prevalent sleep apnea and 1.01 (95% confidence interval 0.87 to 1.16), 1.0 (reference), and 1.12 (95% confidence interval 0.99 to 1.27) for those without sleep apnea, respectively. Our data showed a modestly elevated risk of AF with long sleep duration among United States male physicians. Furthermore, a shorter sleep duration was associated with a greater risk of AF in those with prevalent sleep apnea.

Meta-analysis of p-wave dispersion values in healthy individuals: the influence of clinical characteristics

BACKGROUND

P-wave dispersion (Pd) is an appealing marker for predicting the risk of developing atrial fibrillation. At present, no definitive cutoff value has been determined as to the diagnosis of high-risk patients. Our aims were to evaluate P-wave parameters of healthy subjects published in the literature, determine normal range and weighted means of Pd and P-wave parameters, and investigate the influences of gender, age, and BMI on the weighted results.

METHODS

A systematic search of studies published in PubMed was conducted. Only studies which included control groups of healthy individuals were included.

RESULTS

Of the 657 studies initially identified, 80 were eligible for inclusion. The total number of participants was 6,827. The highest reported Pd values were 58.56 ± 16.24 ms; the lowest were 7 ± 2.7 ms. The weighted mean was 33.46 ± 9.65 ms; weighted median was 32.2 ms. Gender and age were not found to be associated with significant influences on P-wave parameter values. High-normal BMI was not found to be associated with increased P-wave parameter values.

CONCLUSIONS

Pd, Pmax, and Pmin span a wide range of values in healthy individuals. Seemingly, abnormal values were often reported in healthy adults. The high variability of P-wave parameters in healthy individuals, and overlapping of the results with those reported for patients with increased risk for atrial fibrillation, might suggest that this technique has limited sensitivity and specificity. The variability between studies may stem from methodological issues and, therefore, there is a definite need for methodological standardization of Pd measurements.

Acute sleep deprivation is associated with increased atrial electromechanical delay in healthy young adults

BACKGROUND

Sleep deprivation (SD) is known to be associated with an increased incidence of adverse cardiovascular outcome. Atrial electromechanical delay (AEMD) calculated from tissue Doppler imaging has been shown to detect atrial impairment in paroxysmal atrial fibrillation. The aim of the study was to investigate whether AEMD would increase in otherwise healthy young adults with acute SD.

METHODS

Twenty-seven healthy volunteers were included into the study (mean age: 26 ± 3 years). The participants underwent an echocardiographic examination after a night with SD. AEMD defined as the interval from the onset of P wave to the onset of late diastolic Am wave (PA) was calculated from the lateral and septal mitral annulus, and lateral tricuspid annulus (PA lateral, PA septum, and PA tricuspid, respectively).

RESULTS

Subjects had similar values of PA tricuspid duration in milliseconds after the night of sleep debt when compared after regular sleep, whereas they had significantly higher values of PA lateral and PA septal durations (69.05 ± 10.64 ms vs 51.31 ± 11.32 ms, P < 0.001 and 51.75 ± 7.15 ms vs 41.37 ± 8.52 ms, P < 0.001; respectively). Moreover, participants had higher inter-AEMD and intra-AEMD values after the night of sleep debt when compared after regular sleep [30.19 ± 9.84 ms vs 14.72 ± 6.81 ms, P < 0.001 and 12.82 ± 7.09 ms vs 4.41 ± 3.60 ms, P < 0.001; respectively]. Pearson's correlation analyses suggest that inter-AEMD and intra-AEMD were inversely correlated with sleep time (r =-0.628, r =-0.499, r =-0.696, and r =-0.572, respectively [all P < 0.001]).

CONCLUSION

In conclusion, in this cross-sectional study, we clearly found that even one night of SD is associated with higher values of inter-AEMD and intra-AEMD in healthy young adults.

Biological Consequences of Disturbed Sleep: Important Mediators of Health?

There is an extensive literature regarding the immunological and endocrinological consequences of illness, stress, and psychopathology. Yet only a modest literature is available regarding the potential unfavorable effects of chronic sleep loss/disruption on immune and endocrine pathways or on various aspects of health. Given that humans spend approximately 1/3 of their lives asleep, it seems pertinent to evaluate this necessary yet understudied behavior. The evidence overwhelmingly indicates that "excessive" sleep disruption or poor sleep quality/continuity may subsequently increase risk for adverse health outcomes, as well as mortality. This is thought to occur through dysregulation of biological pathways. While our information addressing the immunological or endocrinological consequences of poor sleep is mounting, the majority of evidence stems from epidemiologic and cross-sectional studies. The immune and endocrine systems are dynamic and constantly in flux. Thus, the methodologies and study designs used to understand how sleep affects these systems needs to be as dynamic. Experimental manipulations and longitudinal evaluations are needed to effectively understand sleep as a risk factor for health. Thus, this paper is a primer in which to highlight the immunological and endocrinological consequences of disrupted or disturbed sleep as well as describe how these relationships may impact overall health. It is also meant to spark an interest for future evaluations of how the behavior of sleep is relevant to health.

Assessment of atrial conduction time in patients with familial Mediterranean fever

BACKGROUND

Increased inflammatory activity is known to be a pathophysiologic characteristic of atrial fibrillation. Familial Mediterranean fever (FMF) is a disease characterized by recurrent and sustained increased inflammatory activity. Atrial conduction abnormalities in these patients have not been investigated in terms of P-wave duration, P-wave dispersion (Pd), and atrial electromechanical delay measured by tissue Doppler echocardiography (TDE). We aimed to assess atrial conduction time in patients with FMF.

METHODS

A total of 33 patients with FMF (13 males/20 females, 28.4 +/- 12.5 years), and 33 controls (13 males/20 females, 28.5 +/- 12.1 years) were included. Atrial electromechanical coupling (PA) and intra- and interatrial electromechanical delay were measured with TDE. From the 12-lead electrocardiogram Pd was calculated.

RESULTS

Atrial electromechanical coupling at the left lateral mitral annulus (PA lateral) was significantly higher in FMF patients (58.0 +/- 9.0 vs 51.0 +/- 5.8, P < 0.001). Interatrial (PA lateral-PA tricuspid) and intraatrial electromechanical delay (PA septum-PA tricuspid) were significantly longer in FMF patients (21.3 +/- 7.4 vs 12.9 +/- 4.6, P < 0.001 and 4.7 +/- 5.5 vs 2.1 +/- 1.7, P = 0.01, respectively). Also, Pd and maximum P-wave duration were significantly higher in FMF patients (42.8 +/- 7.9 vs 35.3 +/- 6.1, P < 0.001 and 98.6 +/- 9.0 vs 93.1 +/- 8.5, P = 0.01, respectively). A positive correlation was detected between interatrial electromechanical delay and Pd (r = 0.622, P < 0.001). Plasma level of C-reactive protein (CRP) correlated with interatrial electromechanical delay and Pd (r = 0.733, P < 0.001; and r = 0.427, P < 0.001, respectively).

CONCLUSION

This study shows that atrial electromechanical delay and Pd are prolonged in FMF patients. Atrial electromechanical delay is closely associated with Pd and plasma level of CRP.

Mechanisms of endothelial dysfunction in obstructive sleep apnea

Endothelial activation and inflammation are important mediators of accelerated atherogenesis and consequent increased cardiovascular morbidity in obstructive sleep apnea (OSA). Repetitive episodes of hypoxia/reoxygenation associated with transient cessation of breathing during sleep in OSA resemble ischemia/reperfusion injury and may be the main culprit underlying endothelial dysfunction in OSA. Additional factors such as repetitive arousals resulting in sleep fragmentation and deprivation and individual genetic suseptibility to vascular manifestations of OSA contribute to impaired endothelial function in OSA. The present review focuses on possible mechanisms that underlie endothelial activation and inflammation in OSA.