• Color Doppler flow across the distal right ventricular outflow tract and main pulmonary artery.
• Normal laminar flow across the pulmonary valve
• Trivial pulmonary regurgitation (denoted by the narrow red jet at the point of valve coaptation).

Estimating pulmonary artery pressures from pulmonary regurgitation

• End diastolic PA pressure = Pulmonary regurgitation end diastolic peak gradient + right atrial pressure
• Mean PA pressure = Peak diastolic pulmonary regurgitation gradient + right atrial pressure

This continuous wave spectral Doppler clip across the RVOT and pulmonary valve.  The Doppler envelope at the far left of the screen (above the baseline) demonstrates pulmonary regurgitation.  The peak diastolic velocity (denoted by the symbol PV) and end diastolic velocity (denoted by the symbol E) can be measured and used to estimate the end diastolic PA pressure and Mean PA pressure (see example below).

• Pulmonary valve peak velocity (PV) = 2.0 meters/sec 
• Pulmonary valve end diastolic velocity (E) = 1.5 meters/sec 

Using Bernoulli equation (P = 4V²) the peak gradient can be obtained:

End diastolic PA pressure = 4(1.5)² = 9 mmHg + right atrial pressure

Mean PA pressure = 4 (2.0)² = 16 mmHg + right atrial pressure