Abstract: An in-line, multipolar proximal connector assembly for an implantable stimulation lead is provided which incorporates at least one sensor. Advantageously, the present invention uses straight conductive rods, or wires, to electrically connect the proximal terminals to a multilumen lead body. The straight conductive rods enable the diameter of the lead assembly to remain small. Additional terminals can easily be added by simply decreasing the spacing between terminals and adding additional conductive rods. In one embodiment, insulating spacers are premolded to include protruding portions which interlock with the ring terminals. Recesses within the insulating spacers are dimensioned to self-position the ring terminals a precise distance from the pin terminal according to precise dimensions defined by the VS-1 (or other) standards. In another embodiment, the terminals are injection molded.

Abstract: A physiological sensor forms an integral part of an implantable stimulation/sensing lead used with a medical device, such as a pacemaker. The stimulation/sensing lead includes a tip electrode to which a distal end of a first conductor is connected. The sensor is inserted in series with respective portions of a second conductor. A distal end of the second conductor/sensor is connected to the tip electrode. Operation of the stimulation/sensing lead occurs unipolarly through the first conductor only, with a signal return path being provided through the tip electrode and conductive body fluids. The sensor does not form part of the electrical circuit to the tip electrode, and there are no electrical connections or breaks in the insulation along the entire length of the first conductor.

Abstract: The present invention includes a body implantable lead having a multi-polar proximal connector, at least a first conductor coupled to at least one stimulating electrode, a sensor for sensing at least one physiologic parameter of the body, and a second and a third conductor coupled to the sensor. The sensor is hermetically sealed in a D-shaped housing. Sensor components are mounted onto a microelectronic substrate which is advantageously placed on an inner flat portion of the D-shaped housing. End caps having glass frit sealing rings are used to seal the ends of the shell. A hermetic seal is easily achieved by heating the glass frit such that the glass frit reflows between the end caps and the shell. Advantageously, the sensor terminals are sized to fit snugly within a narrow bore of the end cap which is then welded closed. The D-shaped sensor is placed on a carrier having at least two lumens.

Abstract: An implant tool for use with an endocardial or other implantable lead having an extendable/retractable positive fixation tip includes a hollow cylindrical housing and a custom designed stylet. The cylindrical housing attaches to a proximal end of the implantable lead. The stylet is inserted through the implant tool and into a lumen of the lead. The presence of the stylet, made from a length of relatively stiff wire, helps guide the distal tip of the lead to a desired implant location. The cylindrical housing includes a body portion and an end portion. The end portion is rotatable relative to the body portion. The stylet includes a knob on its proximal end, and also includes a stub pin slightly forward of its proximal end. The stub pin is received within a slot along the side of the cylindrical housing. Two spaced-apart recesses along the length of the slot allow the stub pin to be respectively held therein.

Abstract: A joint assembly which may be used for affixing a helically wound lead conductor coil to an electrode of a pacemaker. The electrode has a longitudinal bore and a coaxial counterbore. One end of the coil is fittingly attached to a reduced diameter end of a press tube. The outer diameter of the extreme outer surface of the coil on the press tube is slightly greater than the inner diameter of the counterbore in the electrode. The reduced diameter end of the press tube with the coil thereon is fittingly inserted into the counterbore. This results in a solid connection between the lead conductor coil and the electrode without causing any visible alteration of the outer surface of the electrode.

Abstract: An implantable medical sensor (42) determines the oxygen content of blood. The sensor includes a miniaturized hybrid circuit (130) that includes light-emitting diode means (32), phototransistor means (34, 36), and a substrate (110) to which the light-emitting diode means and phototransistor means are bonded in a desired circuit configuration. The hybrid circuit is hermetically sealed within a cylindrical body (140) made from a material that is substantially transparent to light, such as glass. Feedthrough terminals (132, 134) provide means for making an electrical connection with the hybrid circuit. The light-emitting diode means is driven with a stair-stepped current pulse. In one embodiment, the sensor is embedded within a bilumen pacemaker lead (60) and positioned near the distal electrode (66) of the lead so that the sensor resides within the heart when the lead is implanted within a patient, thereby allowing the sensed oxygen content (MVO.sub.