Abstract: An implantable lead includes a defibrillation electrode and a sensor coupled thereto. The electrode and sensor are positioned along a body of the lead such that, when a fixation element couples the lead to an endocardial surface of a right ventricle, the sensor is located in a high flow region and a portion of the defibrillation electrode is located in proximity to a right ventricular apex.

Abstract: A medical electrical lead includes a first low voltage electrode adapted for intimate contact with tissue at an implant site, in order to provide pacing stimulation, and a second low voltage electrode positioned in proximity to the first electrode, isolated from the first electrode and adapted to function in conjunction with the first electrode to provide bipolar sensing of near-field signals. A porous layer is formed over the second electrode; the porous layer allows conduction therethrough while preventing contact between the second electrode and tissue in proximity to the implant site.

Abstract: An implantable electrical medical system comprises a low voltage cathode electrode assembly, including a cathode surface adapted for intimate contact with electrically active tissue, and a low voltage anode electrode assembly, including an anode surface and a porous layer extending over the anode surface. The cathode surface and the anode surface function as a bipolar pair for pacing and the porous layer extending over the anode surface allows conduction therethrough and prevents the anode surface from contacting the electrically active tissue in order to prevent anodal stimulation.

Abstract: In general, an apparatus including a lead body and at least two electrodes. The lead body is so shaped that the lead body brings the first electrode against cardiac tissue yet keeps the second electrode away from contact with the cardiac tissue. These electrodes may be separated by a very small distance. When the lead is implanted in the superior vena cava, each electrode generates a distinct voltage signal as a function of sensed electrical activity. Although each electrode may sense a far-field R-wave in addition to a P-wave, the difference between the signals from the electrodes preserves the P-wave but includes a reduced far-field R-wave.