Effect of imaging view and sample volume location on evaluation of mitral flow velocity by pulsed Doppler echocardiography

Abstract

Pulsed Doppler mitral flow velocity measurements have been used to evaluate left ventricular diastolic filling. In normal persons these measurements are affected by age and respiration, but not by gender, body surface area or normal blood pressure. Additional factors that may influence these measurements include the imaging view and sample volume location. In this study, the effects of imaging view and sample volume location were evaluated in 52 normal subjects, aged 21 to 78 years. Pulsed Doppler recordings were obtained from the apical 4-chamber and apical 2-chamber views with the sample volume located both in the left atrium and at the level of the mitral valve leaflet tips. Doppler measurements were slightly, but not significantly, higher (4% on average) for recordings obtained from the apical 4-chamber than from the 2-chamber view for peak flow velocity in both early and late diastole. However, apical 4-chamber recordings from a sample volume in the left atrium resulted in measurements significantly lower (p < 0.05) for both early and late diastolic mitral peak flow velocity than those obtained near the mitral leaflet tips (peak flow velocity in early diastole = 43 ± 12 vs 57 ± 12 cm/s and peak flow velocity in late diastole = 36 ± 7 vs 46 db 11 cm/s, respectively). The higher mitral peak flow velocity values recorded in early and late diastole near the mitral leaflet tips may be related to the smaller flow area at the mitral valve orifice compared with the left atrium. Neither imaging view nor sample volume location resulted in significant differences in the ratio of late-to-early diastolic peak flow velocity. Pulsed Doppler mitral flow velocity measurements must be standardized for sample volume location when evaluating ventricular diastolic filling.