Tissue Doppler of early mitral filling correlates with simulated XXXX in healthy subjects.

@entity1 @entity341 @entity3485 @entity393 @entity65
OBJECTIVES: The accurate noninvasive assessment of preload in @entity341 ( @entity341 ) @entity1 remains elusive. Point-of-care ultrasound (US) imaging, particularly evaluation of the inferior vena cava (IVC), has been shown to be qualitatively helpful. Doppler and tissue Doppler are now routinely available on @entity341 US equipment, but few studies have looked at the correlation of dynamic changes in these parameters in a controlled model of @entity3485 . Our objective was to examine the correlation of Doppler parameters to simulated @entity393 in healthy subjects using a lower-body negative pressure (LBNP) model and to compare these measurements to commonly used IVC measurements of preload. METHODS: Twelve paid volunteers with no known @entity65 between the ages of 23 and 31 years old (mean    SD = 25.5    2.5 years old) were recruited. @entity3485 was simulated using graduated LBNP levels with measurements taken at 0, -30, and -60 mm Hg and lower pressures as tolerated. Vital signs were monitored in all @entity1 . US measurements recorded at each negative pressure level included IVC maximum (IVC(max)) and minimum (IVC(min)) dimensions; early (E) and late (A) transmitral filling velocities using pulsed-wave spectral Doppler; and early (E') and late (A') tissue Doppler velocities at the septal ((sep)) and lateral ((lat)) mitral annulus, using pulsed-wave tissue Doppler. RESULTS: Lower-body negative pressure correlated significantly and positively within subjects for all US parameters except for the A filling wave. E'(lat) and E'(sep) showed the strongest correlation with R   values of 0.749 (95% confidence interval [CI] = 0.577 to 0.854) and 0.738 (95% CI = 0.579 to 0.875) respectively, followed by A'(sep) 0.674 (95% CI = 0.416 to 0.845), IVC(max) 0.638 (95% CI = 0.425 to 0.806), A'(lat) 0.547 (95% CI = 0.280 to 0.802), IVC(min) 0.512 (95% CI = 0.192 to 0.777), and E 0.478 (95% CI = 0.187 to 0.762). Ratios correlated only moderately with LBNP level, including E/ E'(lat) R   of 0.430 (95% CI = 0.131 to 0.706), E/ E'(sep) 0.416 (95% CI = 0.183 to 0.686), and IVC collapsibility index (IVC(CI)) 0.201 (95% CI = 0.003 to 0.681). Vital signs, including heart rate and blood pressure, did not vary significantly with LBNP levels. CONCLUSIONS: In this pilot study of healthy subjects, tissue Doppler assessment of early diastolic filling correlated most strongly with simulated @entity3485 .
