In vivo guided numerical modeling of pulmonary venous waveforms: a paradigm for applied physiology research

The determination of pulmonary venous velocities from pulsed Doppler echocardiography is valuable for the assessment of left ventricular diastolic dysfunction, yet little is known regarding the relationship between actual pressure gradients and measured velocities. Combining results of in vivo experiments and numerical modeling, a linear relationship was observed between actual pulmonary venous-left atrial pressure gradients and measured velocities (convective forces) measured using pulsed Doppler echocardiography. Strong model correlations were observed for the systolic (y=0.20x-0.13, r=0.97) and diastolic (y=0.25x-0.34, r=0.99) phases of the pulmonary venous waveform. In vivo results were similar for the systolic (y=0.234x+0.01x, r=0.82) and diastolic (y=0.22x+0.09, r=0.81) phases. Modeling, combined with in vivo experiments can complement each other in understanding complex physiology.