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Blood pressure, heart rate, sympathetic nerve activity, and polysomnography were recorded during wakefulness and sleep in 10 patients with obstructive sleep apnea. Measurements were also obtained after treatment with continuous positive airway pressure (CPAP) in four patients. Awake sympathetic activity was also measured in 10 age- and sex-matched control(More)
CONTEXT Obstructive sleep apnea (OSA) has been increasingly implicated in the initiation and progression of cardiovascular diseases. OBJECTIVE To systematically review the interactions of OSA with cardiovascular pathophysiology and diseases. DATA SOURCES AND STUDY SELECTION The MEDLINE database from January 1966 to March 2003 was searched using the(More)
BACKGROUND Sympathetic and parasympathetic systems are considered the principal rapidly reacting systems that control heart rate. METHODS AND RESULTS We propose a symbolic analysis series to quantify the prevalence of sympathetic or parasympathetic cardiac modulation. This analysis decomposes the heart rate variability series in patterns lasting 3 beats(More)
BACKGROUND We tested the hypothesis that patients with untreated obstructive sleep apnea (OSA) would be at increased risk for recurrence of atrial fibrillation (AF) after cardioversion. METHODS AND RESULTS We prospectively obtained data on history, echocardiogram, ECG, body mass index, hypertension, diabetes, NYHA functional class, ejection fraction, left(More)
BACKGROUND C-reactive protein (CRP) is synthesized from the liver and is regulated by cytokines, especially interleukin-6. Leptin, the adipocyte-derived protein product of the ob gene, is related to amount of body fat. The long form of the leptin receptor resembles cytokine receptors, which include the interleukin-6 receptor. Both leptin and CRP may be(More)
BACKGROUND Studies of the association between obesity, and total mortality and cardiovascular events in patients with coronary artery disease (CAD) have shown contradictory results. We undertook a systematic review to determine the extent and nature of this association. METHODS We selected cohort studies that provided risk estimates for total mortality,(More)
A unifying general approach to measure regularity, synchronisation and co-ordination is proposed. This approach is based on conditional entropy and is specifically designed to deal with a small amount of data (a few hundred samples). Quantitative and reliable indexes of regularity, synchronisation and co-ordination (ranging from 0 to 1) are derived in a(More)
REPORTS OF A RELATIONSHIP between altitude and circulating levels of leptin suggest a possible role of hypoxia in leptin regulation. However, studies on the changes in plasma leptin levels at altitude are controversial, with some showing an increase and others suggesting no change or a fall in these levels. Exposure to hypoxia has been shown to stimulate(More)
The arterial baroreflex contributes importantly to the short-term regulation of blood pressure and cardiovascular variability. A number of factors (including reflex, humoral, behavioral, and environmental) may influence gain and effectiveness of the baroreflex, as well as cardiovascular variability. Many central neural structures are also involved in the(More)
Sleep is a natural periodic suspension of consciousness during which processes of rest and restoration occur. The cognitive, reparative and regenerative accompaniments of sleep appear to be essential for maintenance of health and homeostasis. This brief overview will examine the cardiovascular responses to normal and disordered sleep, and their physiologic(More)