TY - JOUR
T1 - Noninvasive estimation of transmitral pressure drop across the normal mitral valve in humans
T2 - Importance of convective and inertial forces during left ventricular filling
AU - Firstenberg, Michael S.
AU - Vandervoort, Pieter M.
AU - Greenberg, Neil L.
AU - Smedira, Nicholas G.
AU - McCarthy, Patrick M.
AU - Garcia, Mario J.
AU - Thomas, James D.
N1 - Funding Information:
Supported in part by Grant 93-13880 from the American Heart Association, Greenfield, Texas (JT), a Grant-in-Aid from the American Heart Association Northeast Ohio Affiliate (PV), Grant 1R01HL56688, National Heart Lung and Blood Institute, Bethesda, Maryland (JT), and Grant NCC9-60, National Aeronautics and Space Administration, Houston, Texas (JT).
PY - 2000/11/15
Y1 - 2000/11/15
N2 - OBJECTIVES: We hypothesized that color M-mode (CMM) images could be used to solve the Euler equation, yielding regional pressure gradients along the scanline, which could then be integrated to yield the unsteady Bernoulli equation and estimate noninvasively both the convective and inertial components of the transmitral pressure difference. BACKGROUND: Pulsed and continuous wave Doppler velocity measurements are routinely used clinically to assess severity of stenotic and regurgitant valves. However, only the convective component of the pressure gradient is measured, thereby neglecting the contribution of inertial forces, which may be significant, particularly for nonstenotic valves. Color M-mode provides a spatiotemporal representation of flow across the mitral valve. METHODS: In eight patients undergoing coronary artery bypass grafting, high-fidelity left atrial and ventricular pressure measurements were obtained synchronously with transmitral CMM digital recordings. The instantaneous diastolic transmitral pressure difference was computed from the M-mode spatiotemporal velocity distribution using the unsteady flow form of the Bernoulli equation and was compared to the catheter measurements. RESULTS: From 56 beats in 16 hemodynamic stages, inclusion of the inertial term ([Δp(I)](max) = 1.78 ± 1.30 mm Hg) in the noninvasive pressure difference calculation significantly increased the temporal correlation with catheter-based measurement (r = 0.35 ± 0.24 vs. 0.81 ± 0.15, p < 0.0001). It also allowed an accurate approximation of the peak pressure difference ([Δp(C+I)](max), = 0.95 [Δp(cath)](max) + 0.24, r = 0.96, p < 0.001, error = 0.08 ± 0.54 mm Hg). CONCLUSIONS: Inertial forces are significant components of the maximal pressure drop across the normal mitral valve. These can be accurately estimated noninvasively using CMM recordings of transmittal flow, which should improve the understanding of diastolic filling and function of the heart. (C) 2000 by the American College of Cardiology.
AB - OBJECTIVES: We hypothesized that color M-mode (CMM) images could be used to solve the Euler equation, yielding regional pressure gradients along the scanline, which could then be integrated to yield the unsteady Bernoulli equation and estimate noninvasively both the convective and inertial components of the transmitral pressure difference. BACKGROUND: Pulsed and continuous wave Doppler velocity measurements are routinely used clinically to assess severity of stenotic and regurgitant valves. However, only the convective component of the pressure gradient is measured, thereby neglecting the contribution of inertial forces, which may be significant, particularly for nonstenotic valves. Color M-mode provides a spatiotemporal representation of flow across the mitral valve. METHODS: In eight patients undergoing coronary artery bypass grafting, high-fidelity left atrial and ventricular pressure measurements were obtained synchronously with transmitral CMM digital recordings. The instantaneous diastolic transmitral pressure difference was computed from the M-mode spatiotemporal velocity distribution using the unsteady flow form of the Bernoulli equation and was compared to the catheter measurements. RESULTS: From 56 beats in 16 hemodynamic stages, inclusion of the inertial term ([Δp(I)](max) = 1.78 ± 1.30 mm Hg) in the noninvasive pressure difference calculation significantly increased the temporal correlation with catheter-based measurement (r = 0.35 ± 0.24 vs. 0.81 ± 0.15, p < 0.0001). It also allowed an accurate approximation of the peak pressure difference ([Δp(C+I)](max), = 0.95 [Δp(cath)](max) + 0.24, r = 0.96, p < 0.001, error = 0.08 ± 0.54 mm Hg). CONCLUSIONS: Inertial forces are significant components of the maximal pressure drop across the normal mitral valve. These can be accurately estimated noninvasively using CMM recordings of transmittal flow, which should improve the understanding of diastolic filling and function of the heart. (C) 2000 by the American College of Cardiology.
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U2 - 10.1016/S0735-1097(00)00963-3
DO - 10.1016/S0735-1097(00)00963-3
M3 - Article
C2 - 11092668
AN - SCOPUS:0034669430
SN - 0735-1097
VL - 36
SP - 1942
EP - 1949
JO - Journal of the American College of Cardiology
JF - Journal of the American College of Cardiology
IS - 6
ER -