Abstract 11492: Active Driving Force in Fontan Circulation: Assessment of Respiratory and Ventricular Functions in Single Ventricular Patients Using Wave Intensity
Background: In Fontan circulation, in addition to continuous blood flow dependent on cardiac output, active driving forces with respiration, ventricular diastole, and muscle pump of lower extremities are thought to be relevant. However, these driving forces have not been proven and their effects on Fontan circulation are unclear. In this study, we measured wave intensity (WI), which reflects energy transmission force, and divides WI into respiratory and heartbeat components based on frequency analysis, and detected wave propagating forces in Fontan circulation.
Methods: We performed catheter examinations and measured pressure and velocity simultaneously in bilateral pulmonary arteries of 10 Fontan patients (mean age 28.8 ± 5.3 months) 1 year after operation. We calculated respiratory and cardiac WI by discrete Fourier analysis, and assessed their relation with respiratory and cardiac functions.
Results: Respiratory WI formed two negative peaks during the inspiratory phase, the first backward expansion wave and the second backward compression wave, indicating that inspiration acts as a sucking driving force. In one phrenic nerve palsy case, one pulmonary artery stenosis case, and one systemic-to-pulmonary shunt case, respiratory WI showed a disturbed pattern. On the contrary, cardiac WI showed two negative peaks during the diastolic phase, the first backward compression and the second backward expansion waves. This result suggested that during diastole, venous return would be dammed up by a force such as pulmonary venule collapse or a reflection wave from the ventricle.
Conclusions: Theoretical approach based on wave propagation lead a novel finding that respiratory pump was proven to be a driving force in Fontan circulation, whereas sucking force by ventricular diastole was not detected. Complications, such as phrenic nerve palsy, pulmonary artery stenosis, and systemic-to-pulmonary shunt, could compromise the efficiency in Fontan circulation.
- © 2012 by American Heart Association, Inc.