Calculations

Question 1

Continuity

Answer 1

A1 V1 = A2 V2
For aortic valve…
AVA = VTIlvot x CSAlvot / VTIav
CSA = Pi r^2 (or 0.785d^2 of the LVOT)

Question 2

Simplified Bernoulli
Equation
Assumptions
Caveat

Answer 2

Delta P = 4V^2
Viscous losses and acceleration effects are negligible
Mass density of blood is approximated
Ignores proximal velocity if <1
BUT if proximal V is > 1.5 OR transvalvular V is < 3 then it is included to calc max gradient

Question 3

Proximal isovelocity surface area

PISA

Answer 3

PISA = 2 Pi r^2 * alpha angle/180

Uses continuity principle to solve for EROA, an area.
A1 V1 = A2 V2 where A1 is the surface area of the hemisphere and V1 is the alias velocity and V2 is peak MR velocity and A2 is the EROA

Question 4

EROA by PISA

Answer 4

EROA = PISA / Vpeak
= 2 Pi r^2 * Valias / Vpeak MR

EROA = Rvol / VTImr jet

Question 5

Regurgitant volume (RV)

Answer 5

RV = SVmv - SVlvot or SVav

Or

RV = EROA * VTI (of the MV for MR)

Question 6

Regurgitant fraction

Answer 6

RF = RV / SVmv (for MR)

Question 7

Mitral valve area (MVA)

Answer 7

MVA = 220 / PHT or 760 / DT 
MVA = CSAlvot * VTIlvot / VTImv 
MVA = PISA *Valias / Vpeak inflow

Question 8

Stroke Volume

Cardiac output

Answer 8

SV = CSAlvot * VTIlvot  
SV = 0.785d^2 * VTIlvot 
CO= SV * HR