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Query: UMLS:C0018801 (heart failure)
 72,216 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The prevalence of reported sleep disturbances in a general population is high. Many of the complaints are the result of sleep-related breathing disorders, due mainly to the occurrence of obstructive and central apnoeas. Obstructive sleep apnoea is a fully described and well-recognized entity. Central sleep apnoea (CSA) however, has been poorly studied. There is accumulating evidence that central sleep apnoea should be considered as the end of a spectrum. Instability in the breathing pattern is the main underlying mechanism and is due to the interaction of many factors. Breathing during sleep is dependent on metabolic control and the activity of the respiratory muscles. Decreased chemical drive and/or failing respiratory muscle function are associated with CSA and usually also with ongoing hypoventilation during wakefulness, characterized by chronic daytime hypercapnia. Central respiratory drive can also be inhibited by upper airway reflexes. Mostly, however, CSA occurs as the hallmark of unstable breathing during sleep brought about by an overall increase in loop gain (especially in light sleep stages) and the unmasking of a CO2 threshold. Arousal following central apnoeas acts as an amplification of the instability. Micro electroencephographic (EEG) arousals are often observed as a consequence of CSA. They are responsible for sleep fragmentation and hypersomnolence during the day. The daytime hypersomnolence and complaints of awakenings during sleep in patients with CSA can be striking. CSA can occur in specific pathologies, such as chronic heart failure and (post-traumatic) brain lesions, that are associated with irregular breathing. Treatment strategies are remarkably few in number. Use of nasal ventilation and the inhalation of CO2 are mainly of theoretical interest, since patients do not often tolerate these more invasive therapies. Drug treatment, especially with acetazolamide, is easier to perform. Stimulation of upper airway reflexes, by less invasive methods, seems to be promising for the near future.
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PMID:Central sleep apnoea, pathogenesis and treatment: an overview and perspective. 748 5

This study was designed to determine the impact of central sleep apnea with or without Cheyne-Stokes respiration (CSR) on morbidity and mortality. Central sleep apnea was found in 77 male general medical ward in-patients. Cheyne-Stokes respiration was found in 49 of the 77 men; in 15 men, CSR was severe, ie, > or = 25 percent of the night spent in CSR, in 34 men CSR was mild (1 to 25 percent CSR). Twenty-eight men had central sleep apnea but no CSR. An additional 31 patients had no sleep apnea and no CSR. The patients with severe CSR had more central apneas, more, but shorter desaturations, more awakenings and more wake time during the night, but spent more time in bed than those with no CSR or no apnea. Radiographic evidence was consistent with an association of CSR and heart failure. In addition, patients with severe CSR were at almost twice the risk of dying compared with those with no apnea and had a shorter survival time. Nevertheless, we could not confirm that CSR was an independent predictor of elevated mortality risk, implying that some other factors specific to severe CSR predispose these patients to shorter survival time.
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PMID:Comparison of patients with central sleep apnea. With and without Cheyne-Stokes respiration. 808 59

Central sleep apnea with Cheyne-Stokes respiration (CSR) during sleep affects about 40 % of patients with chronic heart failure (CHF). During CSR simultaneous periodic fluctuations in wakefulness and respiration with accompanying changes in blood pressure and heart rate are observed. CSR can be described as an oscillation of the ventilatory feedback loop controlling respiration. The major synergistically acting mechanisms causing this oscillation include reduced body stores of oxygen and carbon dioxide, hyperventilation with concomitant hypocapnia, prolonged circulation time, and a relatively high hypercapnic ventilatory response. The repetitive desaturations and arousals following CSR cause daytime symptoms and an increase in sympathetic activity. In CHF chronically increased sympathetic activity has negative effects on left ventricular function and is associated with reduced exercise tolerance and poor prognosis. Therefore CSR is expected to have an unfavorable influence on the course of CHF. Whether successful treatment of nocturnal CSR has any impact on the high mortality of CHF needs to be resolved in controlled studies with sufficient sample size.
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PMID:Central sleep apnea and chronic heart failure. 1089 7

To define fundamental mechanisms for sympathoexcitation could provide a therapeutic opportunity to interrupt the specific site linking sympathetic activation with heart failure. Central sleep apnea is characterized by apnea, hypoxia, sleep fragmentation, and increased sympathetic nerve activity. Since this sympathoexcitation is directly related to the frequency of arousals from sleep and the degree of apnea-related hypoxia, but not to left ventricular ejection fraction, it is therefore not simply a compensatory response to hemodynamic derangement but is excessive and pathologic sympathoexcitation with aftereffects that persist into wakefulness. Thus, central sleep apnea could participate in a vicious pathophysiologic cycle involving the cardiovascular, respiratory, and autonomic nervous system.
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PMID:[Autonomic function and circulatory failure]. 1094 19

Ageing is often associated with a decrease in the quality of sleep. In older subjects, sleep-related breathing disorders (SRBD) are increasingly recognized as being responsible for alterations in the quality of sleep. The prevalence of obstructive sleep apnea (OSA) increases with ageing; despite sometimes major disturbances in sleep structure, clinical symptoms are often subtle in this age group. Central apnea and periodic breathing, also more frequent in older subjects, most often occur in patients suffering either from neurological problems (such as tumors, brain infarcts, sequelae of infection, diffuse encephalopathies) or moderate to severe heart failure. In fact, patients suffering from cerebro-vascular diseases (such as brain infarcts or transient ischemic attacks) have a higher prevalence of SRBD than a control age-matched population. In these patients, SRBD are associated with a poorer prognosis in terms of functional recovery and survival. The clinical impact of SRBD on cognitive function appears to be modest in patients without dementia, albeit for a slight increase in daytime somnolence. However, in patients suffering from Alzheimer's disease, SRBD occur more frequently than in non-demented subjects, and indexes of severity of SRBD have been correlated with the importance of cognitive impairment. The hypothesis of a causal relationship between SRBD and the degree neuropsychological impairment in either Alzheimer's disease or multi-infarct dementia remains a matter of controversy. SRBD should be considered as a possible cause of "reversible dementia" and sought for in the presence of daytime somnolence, delirium, or unexplained right-sided heart failure in older patients.
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PMID:[Respiratory sleep disorders in the elderly]. 1114 Mar 5

Central sleep apnoea is often recognized in patients with heart failure. Although the medical treatment to improve cardiac function is effective for sleep apnoea, direct evidence that improved cardiac function ameliorates sleep apnoea has not been reported due to the fact that a particular drug may affect a multitude of organs. We present a chronic heart failure patient with central sleep apnoea whose nocturnal desaturation was improved by percutaneous coronary intervention that resulted in improved cardiac function. This is the first case where percutaneous coronary intervention improved sleep apnoea, suggesting that the improved cardiac function led to amelioration of sleep apnoea.
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PMID:Percutaneous coronary intervention for central sleep apnoea with ischaemic cardiomyopathy. 1503 Jan 36

Sleep apnea encompasses 2 forms of sleep disordered breathing, namely obstructive and central sleep apnea. Both these conditions are prevalent in patients with congestive heart failure (CHF) despite quite different etiology and pathogenesis. The last 15 years have seen the development of a large database of mechanistic data implicating both these conditions in the progression of cardiac dysfunction in patients with heart failure. Epidemiological data have also revealed that obstructive sleep apnea may be an independent risk factor for the development of cardiac diseases. Central sleep apnea, conversely, is more likely to emerge as a consequence of severe cardiac dysfunction, but through an elaborate vicious cycle could potentially lead to augmentation of sympathetic activity and contribute to further cardiac decline. In recent years a number of randomized controlled trials suggests secondary endpoints such as symptoms, sympatho-excitation and left ventricular function can be improved with the effective therapies available for both central and obstructive sleep apnea in patients in which these conditions co-exist. Mortality data is emerging also, and the first of a large scale mortality trial assessing the effect of attenuating central sleep apnea with continuous positive airway pressure in patients with moderate to severe CHF, is well underway. This review summarizes the important mechanistic, epidemiological and interventional studies in relation to sleep apnea and congestive heart failure with some commentary on the future direction of this rapidly growing field.
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PMID:Sleep apnea and congestive heart failure. 1533 41

Heart failure is a highly prevalent disorder, with significant economic impact, and is associated with excess morbidity and mortality. One factor that may contribute to the progressively declining course of heart failure is the occurrence of recurrent episodes of apnea and hypopnea. There are two major kinds of sleep-related breathing disorders: obstructive and central sleep apnea. In patients with heart failure, in contrast to the general population, central sleep apnea is the most common form of sleep-related breathing disorder. Episodes of apnea, hypopnea, and the subsequent hyperpnea cause sleep disruption, arousals, hypoxemia-reoxygenation, hypercapnia/hypocapnia, and changes in intrathoracic pressure. These pathophysiologic consequences of sleep-related breathing disorders have deleterious effects on the cardiovascular system, and may be even more pronounced in the setting of established heart failure and coronary artery disease. Therefore, sleep apnea in heart failure should be treated. Central sleep apnea may be treated with nocturnal supplemental nasal oxygen, theophylline, or nasal-positive pressure devices, such as nasal continuous positive airway pressure (CPAP). The treatment of choice for obstructive sleep apnea is nasal CPAP. Although long-term controlled trials of the effect of treatment of sleep apnea on mortality in patients with heart failure are still pending, treatment of sleep apnea, both obstructive and central, does result in a decrease in sympathetic activity and an improvement in systolic function, which are known surrogates of mortality. Therefore, diagnosis and treatment of sleep-related breathing disorders may increase survival of patients with heart failure.
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PMID:Prevalence and treatment of breathing disorders during sleep in patients with heart failure. 1600 60

Heart failure due to left ventricular systolic dysfunction is a prevalent syndrome and associated with morbidity, mortality, and huge economic cost. According to reports from several laboratories, a large number of patients with heart failure have central sleep apnea. Central sleep apnea causes arousals and sleep disruption, alters blood gases, and increases sympathetic activity. The pathophysiological consequences of central sleep apnea could adversely affect left ventricular structure and functions and worsen prognosis of heart failure. Several treatment options, including use of nocturnal supplemental oxygen, positive airway pressure devices, and theophylline have been systematically studied and have been shown to improve central sleep apnea. Long-term studies, however, are necessary to determine the impact of therapy on natural history of left ventricular systolic dysfunction.
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PMID:Central sleep apnea in congestive heart failure: prevalence, mechanisms, impact, and therapeutic options. 1605 17

Sleep-disordered breathing is very common and is associated with an increased risk of cardiovascular disease, cardiac arrhythmia and stroke. There are two types of sleep apnea: obstructive and central. The objective of this review is to provide a broad perspective of the pathophysiological and clinical aspects of the two types of apnea and to discuss their cardiovascular adverse effects. The diagnosis of sleep apnea syndrome is based on polysomnography, and severity is measured with an apnea-hypopnea index that counts the total number of apneas per hour of sleep. Recent large epidemiologic studies have shown that sleep apnea affects about 16% of men and 5% of women between 30 and 65 years of age. Obstructive sleep apnea is characterized by abnormal collapse of the pharyngeal airway during sleep, snoring, vigorous inspiratory efforts causing frequent arousal, and excessive daytime drowsiness. Central sleep apnea with Cheyne-Stokes respiration is a form of periodic breathing with frequent periods of hyperventilation, and carries a poor prognosis in patients with heart failure. Obstructive apnea can also have substantial health consequences. Although the exact mechanism linking sleep apnea with cardiovascular disease is unknown, there is evidence that obstructive apnea is associated with a group of proinflammatory and prothrombic factors that are also important in the development of atherosclerosis. Nocturnal and daytime sympathetic activity is elevated after sleep apnea. Autonomic abnormalities include an increased resting heart rate, decreased cardiac rhythm activity, and increased blood pressure variability. Obstructive apnea is associated with endothelial dysfunction, increased C-reactive protein and cytokine expression, elevated fibrinogen levels and decreased fibrinolytic activity. Enhanced platelet activity and aggregation, leukocyte adhesion and accumulation of endothelial cells are common in both obstructive apnea and atherosclerosis. Surges in sympathetic activity, blood pressure, ventricular wall tension and afterload adversely affect ventricular function. Many studies have shown that patients with obstructive apnea have an increased incidence of daytime hypertension, and this syndrome is recognized as an independent risk factor for hypertension. Obstructive apnea is associated with myocardial ischemia (silent or symptomatic), acute coronary events, stroke and transient ischemic attacks, cardiac arrhythmia, pulmonary hypertension and heart failure. Central sleep apnea is frequent in severe heart failure. Most heart failure patients with pulmonary congestion chronically hyperventilate because of stimulation of vagal irritant receptors and central and peripheral chemosensitivity. When PaCO2 falls below the threshold required to stimulate breathing, the central drive to respiratory muscles and air inflow ceases and central apnea ensues. Apnea, hypoxia, CO2 retention and arousals provoke elevated sympathetic activity, increased afterload and elevated left ventricular transmural pressure, and promote the progression of heart failure. Tentative relationships have been identified between central apnea and markers of inflammation, oxidative stress and endothelial dysfunction. Recent mid-terms trials showed that nocturnal use of positive airway pressure in patients with the two types of apnea alleviates symptoms, reduces sympathetic activity, improves ventricular function and quality of life, and reduces daytime drowsiness. More studies are needed to understand the mechanisms underlying the relationship between sleep apnea and cardiovascular disease, but clinicians should be aware of this link and should attempt to identify patients with these syndromes.
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PMID:[Sleep apnea syndromes and cardiovascular disease]. 1614 10


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