(738) The Effect of Acute Alterations in Left Atrial Pressure on Rc Time in the Pulmonary Circulation

PurposeThe product of pulmonary vascular resistance (PVR) and artery compliance (PAC) describes the time constant (RC time) circulation. RC integrates parameters which describe steady pulsatile afterload right ventricle. This study investigated effects acute changes in left atrial pressure (LAP) on RC-time using hi-fidelity (PA) waveform analysis.MethodsPatients with ventricular assist devices (LVADs) were recruited during heart catheterization (RHC) clinical ramp was performed to assess change PAC. Pulmonary arterial recorded at highest lowest LVAD speeds Mikrocath catheter sample 1000Hz. Phase plane analysis then 10 consecutive diastolic decay waveforms each speed calculate RC-time.Results5 patients underwent studies simultaneous RHC. Mean wedge (mPAWP) altered acutely by a mean 5mmHg (range 4-6). (mPAP) changed 3 mmHg 0-5) 0.02 WU -1.3-2.0). derived from deviated significantly estimated PVR volume (SV)/pulse (PP) product. Consequently, PAC also SV/PP. Acute increase PAWP resulted shortening RC-time.ConclusionMeasuring direct produces different results PVR*SV/PP. reliably shortens elevations PAWP, suggesting that can augment RV without intrinsic remodelling. Further are needed investigate whether analyses PA provides more meaningful assessment load. The analysis. Patients RC-time. 5 Measuring