Aortic Valve

• LVOT diameter CSA measurements^{1 2}
  • Made at the same level as the velocity recording
  • Used to calculate cross-sectional area (CSA)
    • Using inner edge of the septal endocardium and the anterior mitral leaflet in mid-systole
    • Parallel and adjacent to the aortic valve or at the site of velocity measurement
• AV jet velocity measured by VTI
  • Velocity time integral (VTI) traced from the modal velocity
  • Maximum velocity obtained from the peak of dense velocity curve
• Continuity Equation valve area
  • AVA = (\(CSA_{LVOT}\) x \(VTI_{LVOT}\))/\(VTI_{AV}\)
• Velocity Ratio and VTI Ratio, Dimensionless Index (DI)
  • Used to reduce error related to LVOT area measurements (Removes LVOT CSA from Continuity Equation) to check AVA or when there is an prosthetic AV in place
  • Velocity Ratio = \(V_{LVOT}\)/\(V_{AV}\)