TY - JOUR

T1 - Mitral inertance in humans

T2 - Critical factor in Doppler estimation of transvalvular pressure gradients

AU - Nakatani, Satoshi

AU - Firstenberg, Michael S.

AU - Greenberg, Neil L.

AU - Vandervoort, Pieter M.

AU - Smedira, Nicholas G.

AU - McCarthy, Patrick M.

AU - Thomas, James D.

PY - 2001

Y1 - 2001

N2 - The pressure-velocity relationship across the normal mitral valve is approximated by the Bernoulli equation ΔP = 1/2 ρΔν2 + M · dv/dt, where ΔP is the atrioventricular pressure difference, ρ is blood density, ν is transmitral flow velocity, and M is mitral inertance. Although M is indispensable in assessing transvalvular pressure differences from transmitral flow, this term is poorly understood. We measured intraoperative high-fidelity left atrial and ventricular pressures and simultaneous transmitral flow velocities by using transesophageal echocardiography in 100 beats (8 patients). We computed mean mitral inertance (M̄) by M̄ = ∫(ΔP - 1/2 ·ρν2) dt/∫(dv/dt)dt and we assessed the effect of the inertial term on the transmitral pressure-flow relation. M̄ ranged from 1.03 to 5.96 g/cm2 (mean = 3.82 ± 1.22 g/cm2). ΔP calculated from the simplified Bernoulli equation (ΔP = 1/2·ρν2) lagged behind (44 ± 11 ms) and underestimated the actual peak pressures (2.3 ± 1.1 mmHg). M̄ correlated with left ventricular systolic pressure (r = -0.68, P < 0.0001) and transmitral pressure gradients (r = 0.65, P < 0.0001). Because mitral inertance causes the velocity to lag significantly behind the actual pressure gradient, it needs to be considered when assessing diastolic filling and the pressure difference across normal mitral valves.

AB - The pressure-velocity relationship across the normal mitral valve is approximated by the Bernoulli equation ΔP = 1/2 ρΔν2 + M · dv/dt, where ΔP is the atrioventricular pressure difference, ρ is blood density, ν is transmitral flow velocity, and M is mitral inertance. Although M is indispensable in assessing transvalvular pressure differences from transmitral flow, this term is poorly understood. We measured intraoperative high-fidelity left atrial and ventricular pressures and simultaneous transmitral flow velocities by using transesophageal echocardiography in 100 beats (8 patients). We computed mean mitral inertance (M̄) by M̄ = ∫(ΔP - 1/2 ·ρν2) dt/∫(dv/dt)dt and we assessed the effect of the inertial term on the transmitral pressure-flow relation. M̄ ranged from 1.03 to 5.96 g/cm2 (mean = 3.82 ± 1.22 g/cm2). ΔP calculated from the simplified Bernoulli equation (ΔP = 1/2·ρν2) lagged behind (44 ± 11 ms) and underestimated the actual peak pressures (2.3 ± 1.1 mmHg). M̄ correlated with left ventricular systolic pressure (r = -0.68, P < 0.0001) and transmitral pressure gradients (r = 0.65, P < 0.0001). Because mitral inertance causes the velocity to lag significantly behind the actual pressure gradient, it needs to be considered when assessing diastolic filling and the pressure difference across normal mitral valves.

KW - Doppler echocardiography

KW - Mitral valve

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U2 - 10.1152/ajpheart.2001.280.3.h1340

DO - 10.1152/ajpheart.2001.280.3.h1340

M3 - Article

C2 - 11179082

AN - SCOPUS:0034967046

VL - 280

SP - H1340-H1345

JO - American Journal of Physiology

JF - American Journal of Physiology

SN - 0363-6135

IS - 3 49-3

ER -