Mechanical Damping of the Manometric System Used in the Pressure Gradient Technique

A simple method for introducing mechanical damping in catheter-manometer systems so that a flat frequency response throughout 30 Hz can be realized easily is described. This allows reliable computation of instantaneous blood velocity by the pressure gradient technique, since the bandwidth available, dc to 22 Hz, allows accurate recording of the pressure gradient, even when long catheters are used. Similarly, the first time derivative of the intraventricular pressure pulse can be obtained without difficulty.