Abstract: A chronic myocardial pacing lead for the delivery of stimulation energy to and the sensing of electrical signals from the myocardium of a human heart. In one embodiment the lead is bipolar, having a sleeve electrode implanted into the myocardium and a pad electrode positioned on the epicardium. The lead includes a drug for delivery through the sleeve electrode to the myocardium. The disclosed lead is highly flexible to minimize tissue reaction, this permits the lead to offer relatively low pacing thresholds, high impedance, and excellent sensing in a configuration which is relatively easy to implant.

Abstract: An implantable lead for establishing electrical contact between a medical device and body tissue, in which an active fixation mechanism secures the lead in place while allowing a distal electrode on the lead to mechanically "float" with respect to the body tissue. In one embodiment, the active fixation mechanism comprises a curved hook disposed on the lead at a point spaced proximally back from the distal end of the lead. The curved hook defines a helix around at least a portion of the lead's circumference. A hollow introducer needle is slidably disposed on the lead. The hollow needle provided with a longitudinal slit in a distal section of is length, such that the distal section of the needle can be advanced over the distal end of the lead, past the fixation hook, which is received in the longitudinal slit. With the needle slid over the distal end of the lead, the needle is stabbed tangentially into an implant site, bringing the fixation hook proximal to the surface of the body tissue.

Abstract: An epicardial lead having an electrode extending from the bottom thereof in combination with an anchoring system adapted to secure the lead to the heart without the use of complex procedures or tools. In a preferred embodiment the epicardial lead comprises an electrode body having two oppositely disposed arms, each arm fixed for rotation, each arm having an arcuate anchor mounted to the bottom surface, each arcuate anchor having as the center of the arcuate shape the axis of rotation of the respective arm. Rotating the arms causes each arcuate anchor to move in a circular fashion such that when each arm is moved from an open position to a closed position the respective anchor is moved to engage and move through the cardiac tissue and thereby secure the lead to the heart.

Abstract: A myocardial pacing lead includes two sets of at least two tines placed to oppose each other. The lead is pressed against the epicardium and is rotated until a rough porous tip abrades the epicardium and allows the tip and the first row of tines to penetrate the myocardium. Excessive penetration and lead migration is prevented by the second row of tines which is mounted backward and just proximal from the first row of tines. The first row of tines anchor on the inside surface of the epicardium which prevents dislodgment. Dacron pads on the second row of tines assures chronic fixation by adhering to the outer surface of the patient's epicardium.

Abstract: Colorimetric, fiber optic sensors for measuring pH, PCO.sub.2 and/or other chemical parameters of the blood. The sensors are fabricated using a single optical fiber, which is provided with a chamber at its distal end containing a pH sensitive dye. Located distal to the chamber is a white reflective surface located within 0.04" from the end of the optical fiber, which enhances the performance of the sensor.

Abstract: A threaded pacing electrode assembly for use in implantable electrical leads. The electrode is provided with an exposed portion adapted to make electrical contact with body tissue and with a cylindrical portion proximal to the exposed portion provided with a helical screw thread. A conductor coil which has an inner diameter smaller than the outer diameter of the cylindrical portion is mounted to the exterior of the cylindrical portion, coiled within the screw thread. A transparent insulating sleeve covers the cylindrical portion, is frictionally retained by the thread, and assists in maintaining the conductor coils in contact with the cylindrical portion.