ASSESSMENT OF PULMONARY VENOUS AND TRANSMITRAL FLOW IN CLOSED-CHEST DOGS UNDER VARIOUS LOADING CONDITIONS BY TRANSESOPHAGEAL DOPPLER-ECHOCARDIOGRAPHY

Pulmonary venous flow velocity (PVFVe), pulmonary venous dimension (PV D) and transmitral flow (TMF) velocity were examined under various loa ding conditions in 15 anesthetized closed-chest dogs by transesophagea l Doppler echocardiography (TEE). We also compared PVFVe with pulmonar y venous flow volume (PVFVo) simultaneously in open-chest dogs using a n ultrasonic flow probe. PVFVo decreased by more than 50% and PVD also decreased significantly during preload reduction, while there was no change in PVFVe. This discrepancy between PVFVo and PVFVe was apparent ly due to the collapse of pulmonary veins. TMF consisted of both rapid -filling flow velocity and atrial flow velocity components (R and A), while PVF consisted of systolic and diastolic forward flow velocity co mponents (S and D). The peak values of R, A, S and D and the time-velo city integrals of each wave (RI, AI, SI and DI, respectively) were mea sured. There was a significant correlation between the changes in RI a nd SI/DI during preload reduction (r=0.82, p<0.001) and during afterlo ad increase (r=-0.59, p<0.05). These results suggest that changes in R I with different loading conditions might be attributable to changes i n atrial reservoir volume and conduit volume.