A micromanometer for chronic implantation

Abstract

A micromanometer has been developed for implantation into the ventricles of dogs to obtain high-fidelity recordings of the ventricular-pressure pulse wave. The device consists of a cylindrical epoxy-resin body to which is bonded a thin glass diaphragm, and which contains a linear variable differential transformer excited at 100 kHz. The overall diameter is 3·8 mm and the length is approximately 8·9 mm. A 2·5 mm-diameter p.v.c. tube is attached and carries the excitation and signal wires. A 100 kHz carrier amplifier is used with the device. The damped natural frequency of the manometer is typically 1·5 kHz, with a damping ratio of less than 0·1. The net response of the system is determined by..