This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Heart failure is a serious and common disease with significant mortality and morbidity. Breathing disorders during sleep adversely affect outcomes in heart failure patients. These breathing disorders include Cheyne-Stokes Respiration (CSR) and Obstructive Sleep Apnea (OSA). A small study in 1959 found that changing from the sitting to the supine position caused or aggravated CSR in a small number of awake patients with heart failure. We have observed the same phenomena in a sleeping patient in our laboratory. We propose to study a large group of patients with congestive heart failure (CHF) and left ventricular ejection fraction (LVEF) of less than or equal to 35% to see if changing the sleeping position from reclining to supine causes or aggravates CSR. We will also monitor non-invasively their cardiac hemodynamics at these different sleeping postures to document changes in thoracic fluid content and cardiac performance. Our patients will be selected from those referred to Queen s Medical Center for echocardiography with a diagnosis of CHF, and with a LVEF of less than or equal to 35%. If the patient consents, nurses will screen them for exclusion criteria, record demographics, general medical, cardiac and sleep histories. A comprehensive chemistry panel, electrocardiogram and simple spirometry will be obtained. The patient s database will be reviewed and validated and a heart and lung examination will be performed by the Principal Investigator. The patient will then be referred to the Queen s Sleep laboratory. An overnight polysomnogram (PSG) will be performed with non-invasive impedence cardiography monitoring. Standard PSG parameters, transcutaneous pCO2, together with measures of thoracic fluid content and cardiac performance will be recorde
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