A method for measuring the mean pressure gradient across prosthetic heart valves under in vitro pulsatile flow...

A method is described for measuring the mean pressure gradient that occurs across a prosthetic heart valve over the forward flow phase in a simulated cardiac pumping cycle. The procedure is to simultaneously gate both the pressure signal and a manually controlled reference voltage of opposite polarity. The gated pressure signal is used to charge up a capacitor, while at the same time the gated reference signal is used to remove charge from the capacitor. The reference voltage is equal to the mean value of the pressure gradient voltage when there is zero net voltage on the capacitor. The gating procedure is simple and straightforward. Sample results for the system, which has been used extensively to study valve performance in vitro, are given.