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 considerable amount of information regarding the diastolic filling characteristics of the left ventricle. Patients with congestive heart failure usually complain of increasing dyspnea in left lateral decubitis (LLD) position, compared with the right lateral decubitus (RLD) position which is called trepopnea. In this study, the effects of LLD and RLD positions on mitral flow velocities in patients with systolic or diastolic dysfunction were examined. Sixteen patients with systolic dysfunction (Group I), 16 patients with diastolic 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 integral of mitral total flow during diastole (VTI), transmitral mean gradient during diastole (MGR) were calculated in each decubitis position. In group 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 group 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) and 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 turning 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 pattern is significantly altered by a postural change from the LLD to RLD positions in patients with systolic dysfunction. This may help to explain the trepopnea in these patients
