Sleep-disordered breathing in a general heart failure population: relationships to neurohumoral activation and subjective symptoms

Pathophysiological Mechanisms to Review Association of Atrial Fibrillation in Heart Failure With Obstructive Sleep Apnea

Sleep-disordered breathing (SDB) comprising obstructive sleep apnea (OSA) is found in more than half of patients with heart failure (HF) and may have negative impacts on cardiovascular function. Increased atherosclerotic cardiovascular disease and the development of coronary events and congestive heart failure are associated with OSA. It is associated with a substandard quality of life, increased hospitalizations, and a poor prognosis. Despite its association with severe cardiovascular morbidity and mortality, the condition is frequently underdiagnosed. The substantial clinical evidence has established OSA as an independent risk factor for bradyarrhythmias and tachyarrhythmias in the last decade. The mechanisms which lead to such arrhythmias are uncertain. In short, OSA patients have a significantly elevated risk of HF and atrial fibrillation (AF). The direct correlation between HF, SDB, and cardiac arrhythmias has been poorly understood. The purpose of this study is to get a better understanding of the relation between AF, OSA, and HF by focusing on the pathophysiological mechanisms underlying these conditions. Therefore, we searched for articles to support our association in PubMed and Google Scholar databases.

Daytime sleepiness and napping in nursing-home eligible community dwelling older adults: A mixed methods study

Objectives

To describe perceptions and beliefs about daytime sleepiness and napping along with subjective and objective daytime sleep characteristics in nursing-home eligible community dwelling older adults.

Methods

A mixed methods study; we conducted semi-structured interviews and measured sleep variables via Actigraphy, sleep diary, and Epworth Sleepiness Scale (ESS). Napping was defined as >10 minutes; anything less was considered dozing.

Results

Final sample (n = 40) was primarily female (85%), Black (100%), with a mean age of 72 ± 9.5 years. Few (25%) reported daytime sleepiness (ESS >10). However, average duration of napping per day was 33.1 ± 11.5 minutes with a nap frequency of 2.5 ± 1.5 naps.

Conclusion

Our sample napped frequently throughout the day, yet the majority reported no daytime sleepiness. These older adults did not always recognize napping or how much they napped.

Mechanisms of reduced sleepiness symptoms in heart failure and obstructive sleep apnea

Patients with both heart failure and obstructive sleep apnea often have poor, repeatedly disrupted sleep, and yet they frequently do not complain of excessive daytime sleepiness. Understanding this lack of perceived sleepiness is crucial for the case identification and treatment of obstructive sleep apnea in the heart failure population at high risk of this disease, especially given the association between untreated obstructive sleep apnea and mortality among patients with heart failure. In this review, we present epidemiologic evidence concerning the lack of sleepiness symptoms in heart failure and obstructive sleep apnea, explore possible mechanistic explanations for this relationship, assess the benefits of treatment in this population, discuss implications for clinical practice and explore directions for future research.

A Patient with Heart Failure and Sleep-disordered Breathing Who Presented with Marked Reverse Remodeling by Continuous Positive Airway Pressure Therapy

A 49-year-old Japanese man with worsening dyspnea was admitted with the diagnosis of new-onset heart failure (HF). His HF symptoms improved with standard treatment, but his left ventricular ejection fraction (LVEF) 21% remained unchanged. After he was discharged, he was diagnosed with severe sleep-disordered breathing (SDB). Continuous positive airway pressure (CPAP) therapy was introduced. Seven months later, his cardiac function had greatly improved (LVEF 50%). We report this case of a HF patient with SDB whose cardiac function greatly improved by CPAP therapy, and we discuss the pathophysiologic mechanisms of successful cardiac "reverse remodeling" in this case.

Biomarkers in Sleep Apnea and Heart Failure

PURPOSE OF REVIEW

Sleep-disordered breathing (SDB) is highly prevalent in heart failure (HF) and may confer significant stress to the cardiovascular system and increases the risk for future cardiovascular events. The present review will provide updates on the current understanding of the relationship of SDB and common HF biomarkers and the effect of positive airway pressure therapy on these biomarkers, with particular emphasis in patients with coexisting SDB and HF.

RECENT FINDINGS

Prior studies have examined the relationship between HF biomarkers and SDB, and the effect of SDB treatment on these biomarkers, with less data available in the context of coexisting SDB and HF. Overall, however, the association of SDB and circulating biomarkers has been inconsistent. Further research is needed to elucidate the relationship between biomarkers and SDB in HF, to evaluate the clinical utility of biomarkers over standard methods in large, prospective studies and also to assess the impact of treatment of SDB on these biomarkers in HF via interventional studies.

Associations of Subjective Sleep Quality and Daytime Sleepiness With Cognitive Impairment in Adults and Elders With Heart Failure

This study examined the association of subjective nighttime sleep quality and daytime sleepiness with cognitive impairment in 105 adults (< 60 years old) and 167 elders (≥ 60 years old) with heart failure. Nighttime sleep quality and daytime sleepiness were measured by the Pittsburgh Sleep Quality Index and the Epworth Sleepiness Scale. Cognitive impairment was assessed using a neuropsychological battery measuring attention, memory, and processing speed. Multivariate logistic regression was used. In adults, daytime sleepiness was associated with cognitive impairment, whereas poor nighttime sleep quality was associated with cognitive impairment in elders. Age may play an important role in how sleep impacts cognition in persons with heart failure. Improving nighttime sleep quality and daytime sleepiness in this population may improve cognition.

Sleepiness and activity in heart failure patients with reduced ejection fraction and central sleep-disordered breathing

OBJECTIVE

Patients with heart failure (HF) and sleep disordered breathing (SDB) are typically not sleepy, unlike patients without heart failure. Previous work in HF patients with obstructive SDB suggested that sleepiness was associated with a reduction in daytime activity. The consequences of predominately central SDB on sleepiness in HF are less well understood. The aim of this study was to test the hypothesis that subjective sleepiness is associated with reduced daytime activity in HF patients with central SDB, compared to those without SDB.

METHODS

The Epworth Sleepiness Scale (ESS), nocturnal polysomnography, and 14 days of wrist watch actigraphy were used to assess subjective daytime sleepiness, nocturnal sleep and breathing, and 24-h activity levels, respectively.

RESULTS

A total of 54 patients with HF were studied, nine had obstructive SDB and were removed from further analysis. Of the patients, 23 had HF with predominantly central SDB (HF-CSA; apnea-hypopnea index (AHI) median 20.6 (IQR 12.9-40.2)/h), and 22 had noSDB (HF-noSDB; AHI 3.7 (2.5-5.9)/h). The median patient age was 68 years (range 59-73 years). There were no significant differences either in ESS score (HF-CSA; 8 [4-10] vs. HF-noSDB; 8 (6-12); p = 0.49) or in duration of daytime activity (HF-CSA 14.5 (14.1-15.2) and HF-noSDB 15.1 (14.4-15.3) hours; p = 0.10) between the groups.

CONCLUSION

HF patients with predominately central SDB are not subjectively sleepy compared to those without SDB, despite reduced sleep quality. We speculate that the lack of sleepiness (based on ESS score) may be due to increased sympathetic nerve activity, although further studies are needed due to the small number (n = 5) of sleepy HF-CSA patients. Daytime activity was not different between HF-noSDB and HF-CSA patients.

Determinants of Behavioral Alertness in Adults with Heart Failure

STUDY OBJECTIVES

The primary objective of this study was to describe characteristics of sleep across the three domains of sleep quality, daytime sleepiness, and behavioral alertness in community-dwelling adults with heart failure. The secondary objective was to identify modifiable factors associated with behavioral alertness.

METHODS

A sample of 280 adults with chronic heart failure was enrolled. Widely used, validated, and sensitive measures of sleep quality (Pittsburgh Sleep Quality Index), daytime sleepiness (Epworth Sleepiness Scale, Stanford Sleepiness Scale), and behavioral alertness (Psychomotor Vigilance Test [PVT]) were collected at baseline, 3 and 6 months. Sociodemographic and clinical characteristics, including exercise, were measured at baseline.

RESULTS

Participants were primarily male and functionally compromised with a mean left ventricular ejection fraction of 35 percent. The majority of the sample (73%) reported poor sleep quality. The mean (± SD) Epworth Sleepiness Scale score was low (7.0 ± 4.6), indicating they did not perceive daytime sleepiness. In contrast, behavioral alertness was relatively poor as evidenced by a slow PVT mean response time (3.09 ± 0.76). Participants who reported exercising at least one hour in the past week were more alert and had faster response times than those reporting no exercise.

CONCLUSIONS

Although sleep quality was poor and behavioral alertness was compromised, these heart failure patients did not feel sleepy. Exercise may help to promote behavioral alertness and reduce daytime sleepiness in adults with heart failure.

Sleep-disordered Breathing in Heart Failure - Current State of the Art

Sleep-disordered breathing (SDB), either obstructive sleep apnoea (OSA) or central sleep apnoea (CSA)/Cheyne-Stokes respiration (CSR) and often a combination of the two, is highly prevalent in patients with heart failure (HF), is associated with reduced functional capacity and quality of life, and has a negative prognostic impact. European HF guidelines identify that sleep apnoea is of concern in patients with HF. Continuous positive airway pressure is the treatment of choice for OSA, and adaptive servoventilation (ASV) appears to be the most consistently effective therapy for CSA/CSR while also being able to treat concomitant obstructive events. There is a growing body of evidence that treating SDB in patients with HF, particularly using ASV for CSA/CSR, improves functional outcomes such as HF symptoms, cardiac function, cardiac disease markers, exercise tolerance and quality of life. However, conflicting results have been reported on 'hard' outcomes such as mortality and healthcare utilisation, and the influence of effectively treating SDB, including CSA/CSR, remains to be determined in randomised clinical trials. Two such trials (SERVE-HF and ADVENT-HF) in chronic stable HF and another in post-acute decompensated HF (CAT-HF) are currently underway.

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.

Cardiac arrhythmias and sleep-disordered breathing in patients with heart failure

The relationship between heart failure (HF), sleep-disordered breathing and cardiac arrhythmias is complex and poorly understood. Whereas the frequency of predominantly obstructive sleep apnea in HF patients is low and similar or moderately higher to that observed in the general population, central sleep apnea (CSA) has been observed in approximately 50% of HF patients, depending on the methods used to detect CSA and patient selection. Despite this high prevalence, it is still unclear whether CSA is merely a marker or an independent risk factor for an adverse prognosis in HF patients and whether CSA is associated with an increased risk for supraventricular as well as ventricular arrhythmias in HF patients. The current review focuses on the relationship between CSA and atrial fibrillation as the most common atrial arrhythmia in HF patients, and on the relationship between CSA and ventricular tachycardia and ventricular fibrillation as the most frequent cause of sudden cardiac death in HF patients.

Severe central sleep apnea is associated with atrial fibrillation in patients with left ventricular systolic dysfunction

BACKGROUND

The results of previous studies investigating the association between atrial fibrillation (AF) and central sleep apnea (CSA) in patients with left ventricular (LV) systolic dysfunction are contradictory.

METHODS

We prospectively enrolled 267 patients in this cross-sectional study with LV ejection fractions ≤50%, who were screened for sleep disordered breathing using cardiorespiratory polysomnography after patients with predominantly obstructive sleep apnea or insufficient sleep studies had been excluded.

RESULTS

AF at study entry was found in 70 of 267 patients (26%). CSA with an apnea/hypopnea index (AHI) ≥15/hour was present in 116 patients (43%) and 67 patients (25%) had severe CSA with an AHI > 30/hour. Univariate analysis revealed a significant association between AF and severe CSA, age, male gender, arterial hypertension, left atrial diameter, brain natriuretic peptide, chronic kidney disease, New York Heart Association class, digitalis, and the lack of angiotensin-converting enzyme inhibitors or angiotensin receptor blockers. Multivariate analysis revealed a significant association between AF and severe CSA (odds ratio [OR]: 5.21; 95% confidence interval [CI]: 1.67-16.27, P = 0.01), age (OR: 1.22 per 5-year increase; 95% CI: 1.05-1.40, P = 0.01), left atrial diameter (OR 1.61 per 5-mm increase; 95% CI: 1.22-2.01, P < 0.01), and digitalis (OR: 2.7; 95% CI: 1.26-5.79, P = 0.01).

CONCLUSIONS

AF is associated with severe CSA but not with moderate CSA in addition to age, use of digitalis, and left atrial size in patients with LV systolic dysfunction. Future studies evaluating the potential benefit of adaptive servo-ventilation therapy to prevent AF or to decrease the AF burden in heart failure patients should therefore focus on patients with severe central sleep apnea.

Clinical predictors of sleep apnoea in heart failure outpatients

BACKGROUND

Sleep-disordered breathing (SDB) is common in heart failure patients. Many of them still remain undiagnosed. The aim of this study was to detect clinical predictors of sleep apnoea which may help to identify patients with SDB at a heart failure clinic.

METHODS

We performed an in-home sleep study on 115 consecutive patients from our heart failure clinic. Clinical characteristics, blood samples, daytime sleepiness and quality of life were registered.

RESULTS

Among 115 patients, 52% had moderate to severe SDB. Body Mass Index (BMI) ≥ 30 kg/m² was the only independent predictor of moderate to severe SDB [Odds ratio (OR) = 3.62, 95% Confidence interval (CI) 1.40-9.36, p = 0.008]. Quality of life and level of sleepiness were not significantly associated with SDB. Patients with mild to moderate chronic obstructive pulmonary disease (COPD) were unlikely to have SDB compared with patients without COPD (OR = 0.10, 95% CI 0.02-0.43, p = 0.002). Hypertension was a predictor of having obstructive sleep apnoea (OR = 2.78, 95% CI 1.15-6.75, p = 0.02), while haemoglobin ≥ 15 g/dl was associated with central sleep apnoea (OR = 6.71, 95% CI 1.96-22.99, p = 0.002).

CONCLUSION

BMI ≥ 30 kg/m(2) is associated with moderate to severe SDB, both obstructive and central sleep apnoea. Thus, BMI may be used as one of the selection criteria for referral of heart failure patients to a sleep specialist.

The Relationship between Nocturnal Hypoxemia and Left Ventricular Ejection Fraction in Congestive Heart Failure Patients

Congestive heart failure (CHF) is a major cause of mortality and morbidity. Among patients with heart failure, sleep disordered breathing (SDB) is a common problem. Current evidence suggests that SDB, particularly central SDB, is more prevalent in patients with CHF than in the general population, but it is underdiagnosed as SDB symptoms that are less prevalent in CHF. The main aims of this study were to determine the relationship between nocturnal hypoxemia and left ventricular ejection fraction in patients with chronic heart failure. By means of echocardiography, 108 patients with left ventricular ejection fraction ≤45% were divided into mild, moderate, and severe CHF. Hypoxemia was recorded overnight in the hospital and was measured by portable pulse oximetry. In the 108 patients with CHF, 44 (40.7%) were severe, 17 (15.7%) moderate, and 47 (43.6%) mild CHF. 95 (88%) of patients with CHF had abnormal patterns of nocturnal hypoxemia suggestive of Cheyne-Stokes respiration. Ejection fraction correlated negatively with dip frequency. There was no correlation between nocturnal hypoxemia with BMI and snoring. This study confirms strong associations between sleep apnea and heart disease in patients with CHF. Overnight oximetry is a useful screening test for Cheyne-Stokes respiration in patients with known heart failure.

The contribution of hypoxia to the association between sleep apnoea, insomnia, and cardiovascular mortality in community-dwelling elderly with and without cardiovascular disease

AIMS

This study explores if nightly hypoxia (i.e. percentage of sleep time with oxygen saturation lower than 90% (SaO2<90%)) contributed to the association between sleep-disordered breathing (SDB) and insomnia in community-dwelling elderly with and without cardiovascular disease (CVD). A second aim was to explore a potential cut-off score for hypoxia to predict insomnia and the association of the cut-off with clinical characteristics and cardiovascular mortality.

METHOD

A total of 331 community-dwelling elderly aged 71-87 years underwent one-night polygraphic recordings. The presence of insomnia was recorded by a self-report questionnaire. The presence of CVD was objectively established and mortality data were collected after three and six years.

RESULTS

In both patients with CVD (n=119) or without CVD (n=212) SDB was associated with hypoxia (p<0.005). Only in the patients with CVD was hypoxia associated with insomnia (p<0.001) which mediated an indirect effect (p<0.05) between SDB and insomnia. Hypoxia of more than 1.5% of sleep time with SaO2<90% was found to be a critical level for causing insomnia. According to this criterion 32% (n=39) and 26% (n=55) of those with and without CVD had hypoxia, respectively. These groups did not differ with respect to age, gender, body mass index, diabetes, hypertension, respiratory disease or levels of SDB. However, in the CVD group, hypoxia was associated with cardiovascular mortality at the three-year follow-up (p=0.008) and higher levels of insomnia (p=0.002).

CONCLUSION

In the elderly with CVD, SDB mediated by hypoxia can be associated with more insomnia and a worse prognosis.

Carotid body denervation improves autonomic and cardiac function and attenuates disordered breathing in congestive heart failure

In congestive heart failure (CHF), carotid body (CB) chemoreceptor activity is enhanced and is associated with oscillatory (Cheyne-Stokes) breathing patterns, increased sympathetic nerve activity (SNA) and increased arrhythmia incidence. We hypothesized that denervation of the CB (CBD) chemoreceptors would reduce SNA, reduce apnoea and arrhythmia incidence and improve ventricular function in pacing-induced CHF rabbits. Resting breathing, renal SNA (RSNA) and arrhythmia incidence were measured in three groups of animals: (1) sham CHF/sham-CBD (sham-sham); (2) CHF/sham-CBD (CHF-sham); and (3) CHF/CBD (CHF-CBD). Chemoreflex sensitivity was measured as the RSNA and minute ventilatory (VE) responses to hypoxia and hypercapnia. Respiratory pattern was measured by plethysmography and quantified by an apnoea-hypopnoea index, respiratory rate variability index and the coefficient of variation of tidal volume. Sympatho-respiratory coupling (SRC) was assessed using power spectral analysis and the magnitude of the peak coherence function between tidal volume and RSNA frequency spectra. Arrhythmia incidence and low frequency/high frequency ratio of heart rate variability were assessed using ECG and blood pressure waveforms, respectively. RSNA and VE responses to hypoxia were augmented in CHF-sham and abolished in CHF-CBD animals. Resting RSNA was greater in CHF-sham compared to sham-sham animals (43 ± 5% max vs. 23 ± 2% max, P < 0.05), and this increase was not found in CHF-CBD animals (25 ± 1% max, P < 0.05 vs. CHF-sham). Low frequency/high frequency heart rate variability ratio was similarly increased in CHF and reduced by CBD (P < 0.05). Respiratory rate variability index, coefficient of variation of tidal volume and apnoea-hypopnoea index were increased in CHF-sham animals and reduced in CHF-CBD animals (P < 0.05). SRC (peak coherence) was increased in CHF-sham animals (sham-sham 0.49 ± 0.05; CHF-sham 0.79 ± 0.06), and was attenuated in CHF-CBD animals (0.59 ± 0.05) (P < 0.05 for all comparisons). Arrhythmia incidence was increased in CHF-sham and reduced in CHF-CBD animals (213 ± 58 events h(-1) CHF, 108 ± 48 events h(-1) CHF-CBD, P < 0.05). Furthermore, ventricular systolic (3.8 ± 0.7 vs. 6.3 ± 0.5 ml, P < 0.05) and diastolic (6.3 ± 1.0 vs. 9.1 ± 0.5 ml, P < 0.05) volumes were reduced, and ejection fraction preserved (41 ± 5% vs. 54 ± 2% reduction from pre-pace, P < 0.05) in CHF-CBD compared to CHF-sham rabbits. Similar patterns of changes were observed longitudinally within the CHF-CBD group before and after CBD. In conclusion, CBD is effective in reducing RSNA, SRC and arrhythmia incidence, while improving breathing stability and cardiac function in pacing-induced CHF rabbits.

Sleep apnea and atrial fibrillation; 2012 update

Atrial fibrillation (AF) and obstructive sleep apnea (OSA) are very prevalent diseases in modern society. Recent years have seen the emergence of a wide body of literature suggesting an important association between these two diseases. This review will provide a summary of this evidence as it currently exists. First, it will review the literature suggesting an association between AF and OSA by highlighting the prevalence of AF in OSA, the correlation of AF prevalence with OSA severity and the trend towards increased AF recurrence in patients with OSA after treatment for AF. Second, it will identify the possible pathophysiologic mechanisms for this association. In doing so, it will discuss the investigated effects of intrathoracic pressure changes, autonomic instability and atrial remodeling. Finally, it will review the evidence of the effect of treatment of OSA on AF, highlighting the role of continuous positive airway pressure (CPAP) in the treatment of OSA and its impact on AF prevalence and recurrence.

Inverse relationship of subjective daytime sleepiness to sympathetic activity in patients with heart failure and obstructive sleep apnea

BACKGROUND

Patients with heart failure (HF) and obstructive sleep apnea (OSA) are less sleepy than patients with OSA but without HF. Furthermore, unlike the non-HF population, in the HF population, the degree of daytime sleepiness is not related to the apnea-hypopnea index (AHI). The sympathetic nervous system plays a critical role in alertness. HF and OSA both increase sympathetic nervous system activity (SNA) during wakefulness. We hypothesized that in patients with HF and OSA, the degree of subjective daytime sleepiness would be inversely related to SNA.

METHODS

Daytime muscle SNA (MSNA) was recorded in patients with HF and OSA. Subjective daytime sleepiness was assessed by the Epworth Sleepiness Scale (ESS).

RESULTS

We studied 27 patients with HF and OSA and divided them into two groups based on the median ESS score: a less sleepy group, with an ESS score < 6 (n = 13), and a sleepier group, with an ESS score ≥ 6 (n = 14). The less sleepy group had higher MSNA than did the sleepier group (82.5 ± 9.9 bursts/100 cardiac cycles vs 69.3 ± 18.6 bursts/100 cardiac cycles; P = .037) and a longer sleep-onset latency (33 ± 29 min vs 14 ± 13 min; P = .039). The ESS score was inversely related to MSNA (r = -0.63; P < .001) but not to the AHI, arousal index, or indices of oxygen desaturation.

CONCLUSIONS

In patients with HF and OSA, the degree of subjective daytime sleepiness is inversely related to MSNA. This relationship is likely mediated via central adrenergic alerting mechanisms. These findings help to explain the previously reported lack of daytime hypersomnolence in patients with HF and OSA.

What is the best measure of daytime sleepiness in adults with heart failure?

PURPOSE

To identify the best screening measure of daytime sleepiness in adults with heart failure (HF).

DATA SOURCES

A total of 280 adults with HF completed the Epworth Sleepiness Scale, the Stanford Sleepiness Scale, and a single Likert item measuring daytime sleepiness. The sensitivity and specificity of these self-report measures were assessed in relation to a measure of daytime dysfunction from poor sleep quality.

CONCLUSIONS

Only 16% of the sample reported significant daytime dysfunction because of poor sleep quality. Those reporting daytime dysfunction were likely to be younger (p < .001), to be unmarried (p = .002), to have New York Heart Association (NYHA) functional class IV HF (p = .015), and to report low income (p = .006) and fewer hours of sleep (p = .015). The measure of daytime sleepiness that was most sensitive to daytime dysfunction was a single Likert item measured on a 10-point (1-10) scale. Patients with a score ≥4 were 2.4 times more likely to have daytime dysfunction than those with a score <4.

IMPLICATIONS FOR PRACTICE

Complaints of daytime dysfunction because of poor sleep are not common in adults with HF. Routine use of a single question about daytime sleepiness can help nurse practitioners to identify those HF patients with significant sleep issues that may require further screening.

Symptoms of sleep apnoea in chronic heart failure--results from a prospective cohort study in 1,500 patients

BACKGROUND

In patients with chronic heart failure, sleep-disordered breathing (SDB) is a common co-morbidity worsening prognosis. The aim of this study was to investigate whether assessment of specific symptoms can elucidate presence of SDB in these patients.

METHODS

A prospective questionnaire scoring investigation on possible symptoms of sleep apnoea (nocturia, fatigue, daytime sleepiness, snoring, nocturnal sweating, witnessed apnoea's, nap) was conducted in 1,506 consecutive patients with stable chronic heart failure (LVEF ≤45%, NYHA ≥2). Afterwards, polysomnography or polygraphy, capillary blood gas analysis, echocardiography, and cardiopulmonary exercise testing were performed.

RESULTS

Adjusted for all significant covariates, snoring (p < 0.01) was the only symptom independently associated with OSA, while witnessed apnoeas (p = 0.02) and fatigue (p = 0.03) independently predicted for CSR. As additional parameters, higher BMI (threshold 26.6; p < 0.01) and higher pCO(2) (threshold 37.6 mmHg; p < 0.01) were independently associated with OSA and male gender (p < 0.001) and lower pCO(2) (threshold 35.0 mmHg; p < 0.001) with CSA. Cumulative questionnaire score results did not sufficiently (OSA--sensitivity 0.40, specificity 0.74; CSA--sensitivity 0.57, specificity 0.59) predict SDB.

CONCLUSION

Although in chronic heart failure patients with either OSA or CSA specific symptoms are apparent, combining clinical data, demographic data, and capillary blood gas analysis results appears favourable to determine the presence of SDB.

Implications of Cheyne-Stokes breathing in advanced systolic heart failure

BACKGROUND

Cheyne-Stokes breathing (CSB) has been associated with heart failure (HF) patients for many years; however, its true prevalence and its prognostic implications are still obscure.

HYPOTHESIS

The goal of this study was to investigate the prevalence and the possible prognostic implications of nocturnal CSB in advanced heart failure patients.

METHODS

We performed single night full polysomonography ambulatory sleep studies in 71 HF patients. We analyzed the patients' sleep studies, clinical and laboratory data, and 6 month mortality.

RESULTS

A total of 71 chronic systolic HF patients were analyzed, 60 males, 11 females, age 65 +/- 13 years. Mean left ventricular ejection fraction was 27% +/- 11%. Short episodes of CSB (at least 3 min duration) were present in all patients, and mean CSB duration was 1 hour. CSB duration was associated significantly with both high serum levels of N-terminal prohormone brain natriuretic peptide (NT-proBNP) as well as with 6 month mortality. Log CSB time had a significant correlation with log NT-proBNP (r = 0.5, P<.0001). Based on median CSB duration, the Kaplan-Meier survival curve analysis showed significant association with 6 month mortality (P = .03).

CONCLUSIONS

CSB prevalence in advanced HF patients is higher than previously reported and is associated with increased serum levels of NT-proBNP and higher 6 month mortality.

Self-reported health-related quality of life and sleep disturbances in Taiwanese people with heart failure

BACKGROUND AND RESEARCH OBJECTIVE

Health-related quality of life (HRQOL) has been viewed as the most important clinical outcome of heart failure (HF) management. However, information about the predictors of HRQOL in Taiwanese people with HF is limited, especially for the effects of sleep disturbances on HF.

PURPOSE

The purpose of this study was to identify predictors of HRQOL in Taiwanese people with HF, especially focusing on the extent to which sleep variables are related to HRQOL.

METHODS

A cross-sectional, descriptive correlational design was used. A nonprobability sample of 125 participants was recruited from the outpatient departments of 2 hospitals located in southern Taiwan. Participants were face-to-face individually interviewed to complete the Kansas City Cardiomyopathy Questionnaire, Pittsburgh Sleep Quality Index, Epworth Sleepiness Scale, and Charlson Comorbidity Index. Data for concomitant health problems and HF characteristics were collected from the medical records.

RESULTS

The mean Kansas City Cardiomyopathy Questionnaire overall summary score for HRQOL in this sample was 70.50 (SD, 19.63). Health-related quality of life physical symptom had the highest score, and the psychological satisfaction domain had the lowest. Six predictors of the HRQOL were identified by using a 3-step hierarchical multiple regression analysis with forward method. The predictors were education (R² = 0.09), New York Heart Association functional class (R² = 0.398), Charlson Comorbidity Index number (R² = 2.6), subjective sleep quality (R² = 0.037), sleep disturbances (R² = 0.015), and sleep latency (R² = 0.018), and together they accounted for a total of 58.5% of the variance in HRQOL.

CONCLUSIONS

Nurses should use a holistic perspective to help patients understand and manage the impact of HF on their daily lives. Effective interventions for improving HRQOL should be designed based on patients' needs and lifestyles. The study findings could serve as a baseline for further longitudinal studies to explore the long-term effects of correlates and causal relationships among the variables in this Taiwanese population with HF.

Insomnia symptoms and daytime function in stable heart failure

OBJECTIVES

To evaluate insomnia symptoms and the extent to which they are associated with clinical and demographic patient characteristics, daytime symptoms, and functional performance in patients with stable heart failure (HF).

DESIGN

Cross-sectional, observational.

SETTING

Five structured HF disease management programs in the Northeastern U.S.

PARTICIPANTS

173 stable chronic HF patients

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Full polysomnography was obtained for one night in participants' homes. Participants completed the six-minute walk test, Medical Outcomes Study SF-36, Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index, Multi-Dimensional Assessment of Fatigue Scale, Centers for the Epidemiological Studies of Depression Scale, and questionnaire items eliciting insomnia symptoms (self-reported difficulty initiating and maintaining sleep and waking too early in the morning). Over half of HF patients reported insomnia symptoms. These were associated with increased daytime symptoms (depression, fatigue), excessive daytime sleepiness, and functional performance in models that statistically controlled for clinical and demographic covariates. These relationships were not explained by sleep disordered breathing.

CONCLUSIONS

Insomnia symptoms are common in patients with stable heart failure and are associated with daytime symptoms and decrements in functional performance.

Sleep disordered breathing, daytime symptoms, and functional performance in stable heart failure

STUDY OBJECTIVES

To evaluate characteristics of sleep disordered breathing (SDB); clinical and demographic correlates of SDB; and the extent to which SDB explains functional performance and symptoms in stable heart failure patients receiving care in structured HF disease management programs.

DESIGN

Cross-sectional, observational study.

SETTING

Structured heart failure disease management programs.

PARTICIPANTS

170 stable chronic heart failure patients (mean age = 60.3 +/- 16.8 years; n = 60 [35%] female; n = 50 [29%] African American; left ventricular ejection fraction mean = 32 +/- 14.6).

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Full polysomnography was obtained for one night on participants in their homes. Participants completed the 6-minute walk, 3 days of actigraphy, MOS-SF 36, Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index, Multi-Dimensional Assessment of Fatigue Scale, and the Centers for the Epidemiological Studies of Depression Scale. Fifty-one percent had significant SDB; Sixteen (9%) of the total sample had central sleep apnea. Severe SDB was associated with a 4-fold increase in the likelihood of poor self-reported physical function (OR = 4.15, 95%CI = 1.19-14.57) and CSA was associated with low levels of daytime mobility (OR = 4.09, 95%CI = 1.23-13.62) after controlling for clinical and demographic variables. There were no statistically significant relationships between SDB and daytime symptoms or self-reported sleep, despite poorer objective sleep quality in patients with SDB.

CONCLUSIONS

Severe SDB is associated with poor physical function in patients with stable HF but not with daytime symptoms or self-reported sleep, despite poorer objective sleep quality in patients with SDB.

Sleep disordered breathing, insomnia, and health related quality of life -- a comparison between age and gender matched elderly with heart failure or without cardiovascular disease

AIMS

The aims of this study are (I) to compare the prevalence of sleep disordered breathing (SDB) and insomnia between elderly with heart failure (HF) and age and gender matched elderly without cardiovascular disease (CVD), and (II) to examine the association between HF, SDB and insomnia, as well as their impact on health related quality of life (Hr-QoL).

METHODS

Three hundred and thirty-one elderly (71-87 years) community-living individuals underwent sleep recordings and echocardiography. Questionnaires assessed insomnia and Hr-QoL. Comparisons were made between age and gender matched individuals with HF (n=36) and without CVD (n=36).

RESULTS

The HF group had higher mean apnoea-hypopnoea index (17.6 vs. 6.3, p<0.001). Moderate/severe SDB was found in 42% of those with HF vs. 8% in those without CVD (p=0.001). Those with HF had more difficulties maintaining sleep (DMS) (72% vs. 50%, p=0.05) and excessive daytime sleepiness (EDS) (25% vs. 8%, p=0.05) and scored worse Hr-QoL in five of eight SF-36 domains. In regression analysis SDB had no association to Hr-QoL. DMS associated to the physical-, and non restorative sleep to the mental domain of Hr-QoL. SDB had no correlations to insomnia or EDS.

CONCLUSIONS

SDB, DMS and EDS are more common in elderly with HF. SDB is not an obvious cause for sleep complaints or poor Hr-QoL in elderly.

Sleep-disordered breathing and heart failure: focus on obstructive sleep apnea and treatment with continuous positive airway pressure

BACKGROUND

Among patients with heart failure, sleep-disordered breathing is a common problem, with a prevalence ranging from 24% to 76%. Encompassed within the general category of sleep-disordered breathing are 2 types of sleep apnea: obstructive sleep apnea (OSA) occurs when the oropharyngeal musculature relaxes, causing a collapse of the upper airway, and central sleep apnea occurs when the brain stem fails to stimulate breathing.

METHODS AND RESULTS

This article focuses on the relationship between heart failure and OSA, the treatment of OSA with continuous positive airway pressure (CPAP), and the role of CPAP in improving such effects of heart failure as ejection fraction, blood pressure, sympathetic activity, sleepiness, heart rate, and mortality.

CONCLUSIONS

It is important to distinguish the type of sleep-disordered breathing a patient may have. Further studies are needed to elucidate the effects of CPAP and other therapies.

Prevalence of sleep-disordered breathing in a 316-patient French cohort of stable congestive heart failure

BACKGROUND

Heart failure with systolic dysfunction occurs frequently. Studies in North America and Germany have shown a high prevalence of sleep-disordered breathing in patients with heart failure.

AIMS

To assess the prevalence of sleep-disordered breathing and its associated risk factors in French patients with heart failure.

METHODS

A total of 316patients with stable heart failure and a left ventricular ejection fraction less or equal to 45% underwent polygraphy prospectively to diagnose sleep apnoea syndrome, defined as an apnoea-hypopnoea index greater or equal to 10events/h.

RESULTS

Mean age, left ventricular ejection fraction, and body mass index were 59+/-13years, 30+/-11% and 28+/-6kg/m(2), respectively. The prevalence of sleep breathing disorder was 81% (n=256); 30% of syndromes were classified as central and 70% as obstructive. The mean apnoea-hypopnoea index was high (30+/-3events/h) and a large proportion (41%) of syndromes had an apnoea-hypopnoea index greater or equal to 30events/h. A central sleep apnoea syndrome pattern was associated with more severe heart failure and a more elevated apnoea-hypopnoea index than an obstructive pattern. The prevalence of sleep-disordered breathing was lower in women than in men (64% versus 85%; chi(2)=0.0003) as was its severity (mean apnoea-hypopnoea index 15+/-13events/h versus 27+/-19events/h, p=0.0001).

CONCLUSION

The prevalence of sleep-disordered breathing was high in a French heart failure population, with most syndromes having an obstructive pattern. Prevalence and severity were higher in men than in women.

Sleep-disordered breathing in heart failure and the effect of cardiac resynchronization therapy

Respiratory disturbances during sleep are common in patients with heart failure (HF) and can trigger the occurrence of sleep apnoea or deteriorate pre-existing breathing disorder. This in turn may lead to worsening of the HF itself. Optimal treatment for HF has been found to reduce respiratory disturbances during sleep significantly, whereas cardiac resynchronization therapy (CRT), achieved by biventricular pacing, appears to cause a further reduction in episodes of central type apnoea, although it may also have an effect on episodes of obstructive type. The beneficial effect of CRT is due to the patients' haemodynamic improvement and in the HF amelioration, and not due to some other effect resulting from the electrical stimulation of the heart. However, this therapeutic intervention by itself is insufficient for the effective treatment of respiratory disturbances during sleep and should be considered as an adjunctive treatment in addition to other established therapies.

Sleep disturbance in people with heart failure: implications for self-care

Heart failure (HF) is associated with high levels of sleep disturbance and sleep disorders, including insomnia, periodic limb movements during sleep, and sleep disordered breathing. Recent studies underscore the importance of disturbances in sleep, a multidimensional biobehavioral phenomenon, to the pathophysiological processes associated with the development of HF, excess morbidity and mortality, and decrements in quality of life and functional performance. Managing disturbed sleep requires specific self-care strategies that must be incorporated into other self-care tasks associated with HF. Decrements in functioning associated with disturbed sleep may also have a negative impact on the self-care capacity and self-care behaviors of people with HF. The purposes of this article are to evaluate the state of the science relative to the nature of sleep disturbance experienced by people with HF and to discuss the implications of sleep, sleep disorders, and sleep-promoting interventions for self-care of people with HF.

High impact of depression in heart failure: Early diagnosis and treatment options

Depressive syndromes in chronic heart failure (CHF) are common and are associated with a poorer prognosis, particularly with increased morbidity and mortality. CHF as a severe physical disorder may increase the risk of developing depressive syndromes or vice-versa as an interaction of possible common psycho-organic etiological aspects. Depression in CHF is associated with impaired NYHA status and daily activities, resulting in enhanced hospitalisation rates and medical costs with a great impact on long-term health. Only a fraction of comorbid patients receives antidepressants. Therefore, identification of risk factors and prevention by optimizing cardiological and psychiatric therapeutic strategies appear essential for these patients. Early diagnosis and treatment of both CHF and depression may prevent further pathophysiological effects on the heart and brain. This review gives a comprehensive overview of the occurrence, risk factors and shared pathophysiology of depression in CHF, and focuses on improving insufficient diagnosis and therapy of depression. Special attention is given on the cardiac effects of psychopharmacological and alternate non-pharmacological antidepressant therapy in CHF. Recommendations are made for treating depression in CHF patients for a better prevention of this disabling physical and psychosocial condition.

Metabolic complications of obstructive sleep apnea syndrome

Obstructive sleep apnea syndrome is a widely prevalent disorder, hallmarked by partial or total upper airway obstruction during sleep. These events fracture sleep integrity resulting in chronic partial sleep deprivation with destructive metabolic sequelae, the focus of this review.

Sleep Disturbances in People Living With Heart Failure

Approximately 10% to 70% of people living with chronic heart failure (HF) experience significant sleep disturbances, which have been shown to impair their health-related quality of life and overall functional performance. Research findings, however, report inconsistent conclusions about sleep disturbances and their adverse effects on HF. The purpose of this article is to review several research studies addressing sleep disturbances in patients with HF and to highlight contradictory and inconsistent findings. Further nursing research about the phenomena related to sleep disturbances in people with HF is warranted so that evidence-based assessments and interventions can be tested in the future.

Overnight Change in Brain Natriuretic Peptide Levels in Children With Sleep-Disordered Breathing

STUDY OBJECTIVES

Obstructive sleep-disordered breathing is accompanied by episodic increases in left ventricle afterload due to large negative swings in intrathoracic pressure and repetitive surges in arterial pressure. Brain natriuretic peptide (BNP) is released by ventricular myocytes in response to pressure and volume overload. It was hypothesized that in children with snoring, overnight change in BNP levels is correlated with severity of disturbance in respiration.

DESIGN

Evening and morning plasma levels of BNP were measured in children with snoring referred for polysomnography.

SETTING

A sleep disorders laboratory in a university hospital.

PARTICIPANTS

Twenty-two children with apnea-hypopnea index (AHI) > or = 5/h (mean +/- SD age, 6.4 +/- 2.5 years), 60 children with AHI < 5/h (mean age, 7 +/- 2.9 years), and 27 control subjects without snoring (mean age, 7.8 +/- 3.7 years) were recruited.

MEASUREMENTS AND RESULTS

Overnight change in BNP (log-transformed ratio of morning-to-evening levels) was larger in children with AHI > or = 5/h, compared to those with AHI < 5/h or to control subjects (0.1 +/- 0.19 vs 0.01 +/- 0.14 vs - 0.06 +/- 0.18; p < 0.05). Children with AHI > or = 5/h had an odds ratio of 4.33 (95% confidence interval, 1.34 to 14) for change in peptide levels > 0.15 relatively to subjects with AHI < 5/h. AHI and oxygen saturation of hemoglobin nadir were significant predictors of overnight change in peptide levels.

CONCLUSIONS

In children with snoring, overnight increase in BNP levels is correlated with severity of disturbance in respiration during sleep, which may indicate presence of nocturnal cardiac strain.