RV Inflow
Description
The tricuspid valve can be used to assess the presence of tricuspid valve regurgitation. By utilizing Doppler ultrasound it is possible to reliably estimate PASP in the presence of a tricuspid regurgitation (TR). According to this equation the pressure gradient across an obstruction (like a valve) is directly related to the peak velocity of flow across. The peak velocity of tricuspid regurgitation jet can be measured by CW Doppler interrogation of the tricuspid valve from the apical four chamber and/or parasternal long axis views. Colour Doppler is used to identify the presence of a TR jet as illustrated from this view (it can also be obtained from the apical view). The blue jet occurring in systole seen across the valve is TR.Doppler
Diagram
Modified Bernoulli's equation can then be applied to the velocity of the TR jet obtained by CW Doppler as: PASP = RVSP = RAP + (4 x V2max) Where RVSP is right ventricle systolic pressure, RAP is right atrial pressure (usually taken as 5-7 mmHg) and Vmax is peak velocity of TR jet. To ensure accuracy the angle between the TR jet and line of interrogation should be minimal. This can be achieved by visualization of flow by simultaneous use of colour flow Doppler. PASP will be underestimated in presence of right ventricle systolic dysfunction.