PULMONARY BLOOD-FLOW PROFILES WITH REDUCED RIGHT-VENTRICULAR FUNCTIONIN LAMBS

The determinants of right ventricular (RV) performance with damaged RV free wall, such as occurs with RV infarction, are still unclear. Usin g 20-MHz Doppler ultrasound equipment, we investigated the changes in pulmonary blood flow velocity profiles before and after ligation of th e right coronary artery. RV dp/dt, stroke volume, RV stroke work, aort ic pressure and cardiac output decreased and central venous pressure r ose after the ligation. The RV stroke work - end-diastolic pressure. r elationship indicated impaired RV function following ligation. We obse rved 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 inte rrupted earlier after ligation than before ligation. These alterations in flow are thought to be a consequence of the altered movement of th e RV free wall and ventricular septum induced by RV infarction.