Abstract: A medical electrical lead, which may be useful in coupling an implantable medical device, is comprised of a first and second lead. The first lead has a first electrode coupled adjacent a distal end portion thereof. The distal end portion of the first lead is anchorable in the coronary sinus of a patient. The second lead is coupled with and moveable along the first lead. The second lead has a second electrode located thereon wherein the position of the first and second electrodes may be varied relative to one another by movement of the second lead along the first lead. A rubber tip holds the relative position of each electrode.

Abstract: A medical electrical lead, which may be useful in coupling an implantable medical device, is comprised of a first and second lead. The first lead has a first electrode coupled adjacent a distal end portion thereof. The distal end portion of the first lead is anchorable in the coronary sinus of a patient. The second lead is coupled with and moveable along the first lead. The second lead has a second electrode located thereon wherein the position of the first and second electrodes may be varied relative to one another by movement of the second lead along the first lead. A rubber tip holds the relative position of each electrode.

Abstract: A medical electrical lead, which may be useful in coupling an implantable medical device, is comprised of a first and second lead. The first lead has a first electrode coupled adjacent a distal end portion thereof. The distal end portion of the first lead is anchorable in the coronary sinus of a patient. The second lead is coupled with and moveable along the first lead. The second lead has a second electrode located thereon wherein the position of the first and second electrodes may be varied relative to one another by movement of the second lead along the first lead. A rubber tip holds the relative position of each electrode.

Abstract: There is provided a system and method for continually monitoring the occurrence of contraction during stimulation of skeletal muscle which is employed in a cardiac assist-type system. During delivery of a periodic burst, or train of stimulus pulses, the impedance of the muscle between the electrodes through which the pulses are delivered is monitored, and evaluated to determine whether or not stimulation has been achieved. In a particular embodiment, the impedance and impedance derivative values are accumulated throughout the burst, and assessed to determine whether the impedance change corresponded to a full muscle contraction. In the event of failure to stimulate the muscle to contraction, the system can automatically adjust the pulse output parameters to achieve reliable contraction.

Abstract: A medical electrical lead having active fixation which readily flexes within the cardiac tissue through a fixation mechanism which is temporarily rigid. In a preferred embodiment, the medical electrical lead features a fixation helix constructed from an absorbable material, such as mannitol. In an alternate embodiment a medical electrical lead is disclosed which features a fixation mechanism having a multi-layer construction. In that embodiment the fixation mechanism is fashioned of a first, rigid and absorbable, material and a second, readily pliable and nonabsorbable, material. Through such a construction the lead may be fixed in the tissue such that over time the first material is absorbed by the body and the second material is left in position to flexibly fix the lead in place. In one embodiment the second material is conductive and is used to achieve an electrical coupling to the body tissue.

Abstract: A technique for monitoring the performance of a skeletal muscle used in a cardiac assist sytem. The skeletal muscle is surgically wrapped about the heart, the descending aorta, or a chamber connected in series with or parallel to the descending aorta to provide direct assistance when electrically stimulated to correspond with naturally or artifically paced heart contractions. An alternate system provides indirect assistance by improving coronary perfusion when the skeletal muscle is electrically stimulated to contract about an artificial chamber during relaxation of the myocardium. In either type or cardiac assist system, the skeletal muscle must be conditioned to perform constant contraction/relaxation within the range of normal heart rates. This conditioning occurs over a length of time which is too long to be directly managed by medical personnel in a sterile environment except experimentally. The present invention provides apparatus and techniques for managing the conditioning process automatically.

Abstract: An intramuscular lead for electrically stimulating muscle tissue particularly configured for a cardiac assist system powered by surgically modified skeletal muscle tissue. Electrical stimulation is supplied via the intramuscular lead to cause contraction of the skeletal muscle in synchrony with the natural or artificially paced heart rate and timed to obtain the desired hemodynamic effect. The improved lead has an electrode which is embedded in the skeletal muscle. The stimulation threshold of the skeletal muscle is held relatively low by the action of a glucocorticosteroid imbedded within the strand of suture material. A spacer coil of biocompatible material is coiled around the strand of suture material, such that the turns of both coils are substantially interleaved. The spacer coil is saturated with a specific agent such as steroid or antibiotic. The compression movement of the muscle tissue and the electrode coil against the spacer coil will cause the drug to be dispensed therefrom.

Abstract: Apparatus and method of controlling a muscle stimulator by varying the duty cycle. The muscle stimulator is particularly adapted to a skeletal muscle powered cardiac assist system. An activity or other sensor is used to determine the requirement for cardiac output. A second electrical sensor is used to determine the cardiac rate. The outputs of these two sensors are employed to select a duty cycle for muscle stimulation of the skeletal muscle. The duty cycle is lowered for reasons of efficiency and safety during periods of very high or very low cardiac rate or body activity. The number of stimulation pulses within a burst is similarly increased when cardiac demand is high to ensure maximum contractile force of the skeletal muscle during each stimulation burst.

Abstract: Apparatus and method for monitoring the performance of skeletal muscle used in a skeletal muscle powered cardiac assist system. The monitoring is performed by an oxygen sensor which determines the adequacy of circulatory support to the skeletal muscle. An adequately supported skeletal msucle can offer the desired cardiac assistance chronically. Insufficient support indicates that the skeletal muscle will easily fatigue until adequate vascularization is achieved. If the circulatory support is chronically insufficient, the risk of ischemia becomes high and additional surgical intervention may be required.

Abstract: An improved lead for electrically stimulating muscle tissue particularly configured for a cardiac assist system powered by surgically modified skeletal muscle tissue. The skeletal muscle is either wrapped about the heart itself, or about an auxiliary pumping chamber attached to the aorta. Electrical stimulation is supplied via the improved lead to cause contraction of the skeletal muscle in synchronism with the natural or artificially paced heart rate and timed to obtain the desired hemodynamic effect. The improved lead has an electrode which is embedded in the skeletal muscle. The stimulation threshold of the skeletal muscle is held relatively low by the action of a glucocorticosteroid imbedded within the suture material. By placing the drug material in this position, it acts as an anti-inflammatory along the entire path of the suture material and treats the specific area of the electrode contact from within the muscle itself.

Abstract: Each segment of a display device, e.g., a seven-segment display comprises at least one shutter normally obturating a cavity in a carrier on a base plate. Each shutter is suspended by two resilient attachments and can turn about a torsion axis established by these attachments under the influence of an electric field applied between a common electrode on a transparent cover plate and an electrode, individual to the shutter at the bottom of its cavity. An optical contrast is provided by light reflection or absorbance caused by a shutter remaining in a rest obturating position or rotating to an open position to allow light absorption in an absorbing layer backing the base plate which is transparent. A selective light transmission (light valve) construction is equally possible. The shutters themselves may be used as one electrode of each pair, with the torsion axis along a shutter edge.