Pulmonary blood flow profiles with reduced right ventricular function in lambs.

The determinants of right ventricular (RV) performance with damaged RV free wall, such as occurs with RV infarction, are still unclear. Using 20-MHz Doppler ultrasound equipment, we investigated the changes in pulmonary blood flow velocity profiles before and after ligation of the right coronary artery. RV dp/dt, stroke volume, RV stroke work, aortic pressure and cardiac output decreased and central venous pressure rose after the ligation. The RV stroke work-end-diastolic pressure relationship indicated impaired RV function following ligation. We observed shortened acceleration time (65.0 +/- 15.1 vs 54.4 +/- 6.2 ms, P < 0.05) and reduced maximum velocity of forward flow (59.0 +/- 5.9 vs 52.5 +/- 7.6 cm/s, P < 0.05) after the ligation. Acceleration was interrupted earlier after ligation than before ligation. These alterations in flow are thought to be a consequence of the altered movement of the RV free wall and ventricular septum induced by RV infarction.