Calculations

Question 1

Simplified Bernoulli.

Answer 1

△P = 4V*2

Question 2

Long-form Bernoulli.

Answer 2

△P = 4 X (V22 - V12)

Question 3

△Pmean can be estimated from △Pmax using the following equation.

Answer 3

△Pmean = (△Pmax/1.45) + 2mmHg

Question 4

What does △Pmean approximate?

Answer 4

2.4V*2

Question 5

EOA(AV)

Answer 5

EOA(AV) = (CSALVOT X VTILVOT)/VTIAV

Question 6

Some versions of the continuity equation use the ratio of what in the LVOT/AOV instead of using VTIs?

Answer 6

Peak Velocities.

Question 7

Zva (valvular-arterial impedance)

Answer 7

Zva = (PGmean + systolic BP)/SVi

Question 8

MVA (continuity equation)

Answer 8

MVA = SVmv/VTImv

Question 9

Stroke Volume

Answer 9

SV = CSA X VTI

Question 10

CSA

Answer 10

CSA = 0.785 X d2 OR CSA = π X r2

Question 11

MVA (pressure half-time equation)

Answer 11

MVA = 220/PHT

Question 12

RVSP

Answer 12

RVSP = 4V*2 + RAP

Question 13

Flow Rate

Answer 13

Flow Rate = Area X Velocity.

Question 14

Regurgitant Volume (MR)

Answer 14

RV = SVmv - SVlvot

Question 15

Regurgitant Fraction (MR)

Answer 15

RF = (RV/SVmv) X 100

Question 16

PISA

Answer 16

PISA = 2πr*2

Question 17

EROA (continuity equation)

Answer 17

EROA = (2πr*2 X Nyquist Limit)/Vmax(mr)

Question 18

EROA (regurgitant volume) - MR

Answer 18

EROA = RV/VTImr

Question 19

Regurgitant Volume (AR)

Answer 19

RV = SVlvot - SVmv

Question 20

Regurgitant Fraction (AR)

Answer 20

RF = (RV/SVlvot) X 100

Question 21

EROA (regurgitant volume) - AR

Answer 21

EROA = RV/VTIar

Question 22

How can Tricuspid valve area be calculated from PHT?

Answer 22

TVA = 190/PHT

Question 23

How is regurgitant flow rate calculated?

Answer 23

Regurgitant flow rate = PISA x Aliasing Velocity.

Question 24

PASP (in the presence of pulmonary stenosis).

Answer 24

PASP = (4Vtr2 + RAP) - 4Vps2

Question 25

How is the HV systolic filling fraction calculated?

Answer 25

HVSFF = S velocity/(S velocity + D velocity) X 100.

Question 26

FAC (fractional area change) of the RV involves manual tracing of the RV endocardial border at end-diastole and end-systole. How has FAC calculated?

Answer 26

FAC = (RVAdiastole - RVAsystole)/RVAdiastole X100.

Question 27

How can PA diastolic pressures be estimated?

Answer 27

``` 4 X (PR end-diastolic velocity)*2 + RA pressure. Same as PASP but by using PR end-diastolic velocity rather than the TR velocity. ```

Question 28

How is LV mass calculated?

Answer 28

LV mass = 0.8 {1.04 X [(LVIDd + LVPWd + IVSd)*3 - (LVIDd)*3]} + 0.6g

Question 29

When calculating LV mass, which should particular care be taken when measuring 2D measurements?

Answer 29

As errors are amplified by cubing.

Question 30

How is relative wall thickness calculated?

Answer 30

RWT = (2 X LVPWd) / LVIDd.