Aortic pressure with asynchronous ventricular assist

The authors have examined the relation between Pao (aortic pressure) and parameters of an asynchronous VAD (ventricular assist device) in a lumped-parameter simulation. While left ventricular volume was greater than a threshold level Vth, the 50 ml VAD chamber filled passively at 100 ml/sec. The VAD emptied at a rate of 400 ml/sec when filled. The ventricular elastance (1/C) followed a half-rectified sine waveform. Over a wide range of heart rates determined by Vth, VAD pumping was entrained synchronous to ventricular pumping by this protocol. With the VAD included, Pao(t) waveform complexity increased, with generally more high-frequency signal energy. This has implications for baroreceptor reflex function in VAD patients