HemodynamicsBlood PressureSleep DisordersCardiac OutputVascular ResistanceHeart RateBlood Flow VelocityCerebrovascular CirculationTime FactorsRegional Blood FlowBlood VolumeDogsModels, CardiovascularMagnetic Resonance ImagingHypotensionHeart FailurePulmonary Wedge PressureTreatment OutcomeOxygenCatheterization, Swan-Ganz