Abstract: An improved electrocardial lead for use with an automatic implantable cardioverter/defibrillator (AICD) comprises an elongated, flexible, plastic tubular catheter body which is preformed so that when unconstrained, it assumes the shape of a tapered spiral or helix. The catheter body supports a defibrillating electrode attached to the exterior wall of the catheter body and is connected by a suitable cable to a proximal connector for mating with the AICD pulse generator. The improved lead also includes a tip electrode for sensing cardiac activity and providing information to the AICD pulse generator for controlling its operation. The lead of the present invention is intended for endocardial emplacement with the electrode structures predominantly in the right ventricle and provides substantially increased electrode surface area in contact with heart tissue as compared to prior art endocardial defibrillating leads and, thus, maximizing the energy delivered to the heart during defibrillation.

Abstract: An implantable defibrillation/cardioversion system and method comprising an electrode having a plurality of discrete electrically conductive segments. The conductive segments are electrically isolated from each other and electrically connected to a defibrillation/cardioversion unit. An electrical pulse block is generated and chopped into a plurality of discrete pulse segments by the defibrillation/cardioversion unit and applied to the electrode so that each conductive segment receives a particular electrical pulse assigned from the series of pulses. In this way, the concentration of gas generated from ionic current produced by a high energy defibrillation pulse is reduces and more energy is delivered to the heart, thus reducing the required energy input to the electrode. The electrode may be planar or in a catheter electrode configuration.

Abstract: An implantable cardiac pacing lead includes a porous, platinum electrode, a flexible electrically conductive coil, and a crimp tube coupling the electrode to the distal end of the coil. A recess in the crimp tube, open to the electrode at the crimp tube distal end, houses a matrix impregnated with a therapeutic drug. The electrode is highly porous and loaded with a therapeutic drug in liquid or solid form. Immediately upon implant of the electrode at a selected myocardial location, the electrode begins dispensing the therapeutic drug. Meanwhile, the matrix begins to elute its drug at a rate more suited to chronic treatment. If desired, the recess can extend through the crimp tube to permit proximal end loading of the drug carrying matrix. A silicone plug, or an additional and proximal crimp tube section, is inserted into the recess after loading of the matrix to provide the required fluid seal.

Abstract: A positive fixation cardiac lead includes an electrode sleeve/crimp tube assembly in which a recess is formed for retaining a drug impregnated matrix. The electrode sleeve and crimp tube threadedly engage, to permit insertion of the matrix prior to their assembly. The distal end section of the crimp tube can be provided with a helical groove corresponding to the shape of a fixation helix, with the sleeve and distal section spaced from one another to permit insertion of an annular drug matrix. The distal portion of the electrode sleeve can have an annular groove formed to receive a length of platinum wire, for increased electrode sensitivity.