The Influence of Gravity on Pulmonary Venous Flow Velocity Patterns : Analysis of the Left and Right Pulmonary Venous Flow Velocities in Both the Left and Right Decubitus Positions

Chisato Izumi, MD、Kanji Iga, MD．Yoshihiro Himura, MD　Ｈiromitsu Gen, MD 、Takashi Konishi, MD

Abstract

Background

The pulmonary venous flow signal measured by transesophageal echocardiography is generally recorded from the left upper pulmonary vein in the left lateral decubitus position, while that by transthoracic echocardiography is from the right upper pulmonary vein in the left semi-lateral decubitus position. The purpose of this study was to evaluate the influence of the postural change on the peak flow velocities of the left and right pulmonary veins and whether each parameter of the pulmonary venous flow can be evaluated interchangeably.

Methods

The study group consisted of 37 patients with normal left ventricular filling pressure in whom the systolic forward flow signals from both pulmonary veins recorded in the left and right lateral decubitus position were clear enough to differentiate as biphasic.

Results

The peak early systolic (peak S1) and diastolic velocities were significantly increased when the pulmonary vein was on the recumbent subject's upper side, while the peak late systolic velocity (peak S2) was significantly increased when it was on the recumbent subject's lower side. The peak S1 was higher than the peak S2 when the pulmonary vein was on the recumbent subject's upper side, while the reverse relationship was seen when the pulmonary vein was on the recumbent subject's lower side.

Conclusions

We should take into consideration the body position and the side on which the pulmonary vein is situated in evaluating the peak flow velocities of the pulmonary veins.