Echocardiographic estimation of pulmonary pressures.

Cardiac ultrasound plays a pivotal role in assessing pulmonary artery pressures. Estimation of right atrial pressure can be derived from the dimensions and respiratory variation of the inferior vena cava and Doppler modalities provide an accurate and comprehensive evaluation of right ventricular and pulmonary artery pressures. Peak pulmonary artery pressure can be calculated from continuous wave Doppler sampling of the tricuspid regurgitant jet, while pulsed wave Doppler sampling of the pulmonary regurgitant jet allows evaluation of mean and diastolic pulmonary artery pressures. In patients with tricuspid regurgitation that is either absent or not adequately detectable by Doppler method, Doppler right ventricular outflow tract investigation can be helpful. Recent data indicate that analysis of right ventricular function using myocardial Doppler echocardiography may also provide new insights for the non-invasive estimation of pulmonary artery pressures. In particular, right ventricular isovolumic relaxation time measured by myocardial Doppler echocardiography at the tricuspid annulus may provide an alternative method for estimating pulmonary artery pressure, especially in patients with tricuspid regurgitation not detectable or spectral Doppler not properly interpretable.