Abstract: Pacer mediated tachycardia (PMT) is detected while the pacemaker is in the host and automatically suppressed and at the same time an indication that tachycardia has occurred and been suppressed is produced so that corrective action can be taken. The pacemaker, operating in the DDD mode, is monitored during operation. On the detection of PMT, the post ventricular atrial refractory period (PVARP) is automatically set and maintained at a magnitude, of 500 or 550 ms, substantially greater than the time of retrograde conduction from the ventricle to the atrium on the occurrence of a pulse in the ventricle. At the same time, the operation of the pacemaker is transferred from the DDD mode to the DDT mode. This transition provides an indication the PMT has occurred so that the physician can correct the operation of the pacemaker. Where PMT has occurred and been suppressed by lengthening the PVARP, the PVARP is reset to start timing out on the occurrence of a ventricular event.

Abstract: A dual chamber pacing lead requiring but a single transvenous pass for implantation. The ventricular electrode has tines for sustaining acute and chronic fixation. The ventricular electrode is coupled to a first conductor which is space wound having an insulation sheath. The proximal end of the first space wound coil protrudes slideably from a first connector pin of a bifurcated connector assembly. An optional stylet may be inserted into the first space wound coil to assist in ventricular placement. A second space wound coil is slideably located over the first space wound coil. The second space wound coil serves as a support means rather than a conductor. The proximal end of the second space wound coil is fixedly attached to the connector assembly. The first space wound coil protrudes near the distal end of the second space wound coil.

Abstract: A heart pacer to be implanted between the pectoralis major muscle and the skin a short distance below the clavicle having an outer container in the shape of an ovaloid. Such a heart pacer adapts itself positionally, cosmetically and with a minimum of discomfort to implantation.

Abstract: A transvenous lead including a conductor encased in an insulating material which is generally inert in body fluids and tissues, the conductor being connected to an exposed, electrically conductive electrode at, or adjacent to, the lead terminus. At least one tine extends from the casing adjacent the lead terminus for engaging the inner wall or trabeculae of an internal body organ or chamber to urge the electrode in a given generally transverse direction, all of such tines extending from the casing in directions which fall within an 180.degree. arc around its periphery with no tine extending in a direction less than 90.degree. from the given direction. In one preferred embodiment, the electrode forms a conductive lead tip and includes a portion skewed toward the given direction.

Abstract: A heart pacer to be implanted between the pectoralis major muscle and the skin a short distance below the clavicle having an outer container in the shape of an ovaloid.[...]. .Iadd.being, except where the heart lead is connected, curved in all dimensions and free of corners and shape ends. .Iaddend.Such a heart pacer adapts itself positionally, cosmetically and with a minimum of discomfort to implantation.