Right ventricular function during left ventricular assistance evaluated by two-dimensional echocardiography

Summary

Right ventricular (RV) function during left heart bypass (LHB) using centrifugal blood pumps was studied in 20 mongrel dogs, which were divided into normal and failing heart groups. RV function was evaluated hemodynamically and by a 2D echocardiography method. Incremental changes in LHB flow ratio from control, 25%, 50%, 75% to the maximum of 85%–100% resulted in decrements of the interventricular septum (IVS) segmental shortening fraction (SSF) from 54%±12%, 43%±5%,42% ±2%, 35%±7% to 1%, respectively. When the LHB ratio was increased from 75% to the maximum level, significant reduction in the RV ejection fraction and a completely depressed left ventricle (LV) were observed. The cross-sectional echo image also revealed profoundly depressed SSF of the IVS and of the nearby RV wall. The LV decompression with the maximum LHB seemed to decrease the contraction capability of the LV wall, including the IVS subsequently causing reduction of the RV wall. This finding was more pronounced in the failing heart group. The excessive LHB for a prolonged duration not only reduces the RV wall contraction capability but may lead to right heart failure.

Our result, therefore, suggests that the LHB ratio of about 75% is optimum for maintenance of normal cardiac function, particularly that of the right heart.