Effect of left and right lateral decubitus positions on mitral flow pattern by Doppler echocardiography in patients with systolic or diastolic dysfunction

Doppler echocardiographic asessment of the mitral valve provides a consider able amount of information regarding the diastolic filling characteristics of the left ventricle. Patients with congestive heart failure usually compl ain of increasing dyspnea in left lateral decubitis (LLD) position, compare d with the right lateral decubitus (RLD) position which is called trepopnea . In this study, the effects of LLD and RLD positions on mitral flow veloci ties in patients with systolic or diastolic dysfunction were examined. Sixt een patients with systolic dysfunction (Group I), 16 patients with diastoli c dysfunction (Group 2), and 16 normal subjects (control group) constituted the study group. Peak early diastolic (E) and atrial (A) flow velocities, EIA ratios, deceleration time (DT), flow duration (PD), the velocity time i ntegral of mitral total flow during diastole (VTI), transmitral mean gradie nt during diastole (MGR) were calculated in each decubitis position. In gro up I; DT was shorter, VTI and FD were significantly lower and E/A ratio was significantly higher than normal control subjects in LLD position. In grou p I, RLD position resulted in an increase in DT (124.81 +/- 21.6, 155.6 +/- 23,p = 0.004), increase in VTI (0.13 +/- 0.03, 0.16 +/- 0.09, p = 0.02) an d a decrease in E/A ratio (1.92 +/- 1, 1.62 +/- 0.88, p = 0.006) suggesting a decrease in left ventricular preload on changing position. On the other hand, no significant change on mitral flow pattern was detected after turni ng over the RLD position in patients with diastolic dysfunction. There was also no significant mitral flow change in the control group on RLD position . The results of this study suggest that the Doppler derived mitral flow pa ttern is significantly altered by a postural change from the LLD to RLD pos itions in patients with systolic dysfunction. This may help to explain the trepopnea in these patients.