Abstract: In the cardiac pacer lead construction disclosed herein, long life and fatigue resistance is obtained by utilizing as a conductive element a thread of conductive carbon filaments in a resin matrix. The thread is helically wound between a stimulation electrode structure at the distal end of the lead and a terminal at the proximal end, the terminal being adapted for connection to a stimulation pulse generating circuit.

Abstract: The dual pressure valve assembly disclosed herein is adapted for use in a ventricular shunt system and comprises a housing enclosing a pair of one-way, pressure biased valves. One of the valves is fixed in place and the second valve is adapted for shifting between an on-line position, in which the valves are in series and their bias pressures combined, and an off-line position in which the second valve is bypassed.

Abstract: In the implantable pressure sensor disclosed herein, a radio-opaque liquid is contained within a resiliently compressible vessel of a silicone rubber, the volume of liquid actually contained within the vessel being then variable as a function of the pressure or force applied to the vessel. The silicone rubber is rendered impervious to the radio-opaque liquid by a treatment which involves expandng and saturating the cured silicone rubber with a mixture of a hydrocarbon solvent such as heptane containing a dissolved wax such as beeswax. The solvent expands and saturates the silicone rubber, carrying beeswax into the silicone rubber. When the solvent evaporates, the beeswax is then trapped within the interstices of the silicone rubber, under tension.