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: A method and apparatus for accessing a nonvolatile electrically erasable programmable read only memory (EEPROM) following hermetic closure of a device containing the EEPROM. The EEPROM is accessed by a direct connection to a feedthrough pin extending through the hermetic enclosure. Following hermetic sealing, the memory is still accessible for programming.In the implantable medical device field, the invention may be utilized to program in the device serial number or similar data which may be telemetered out of the device on command of an external programmer/transciever in order to identify the device. In a specific application, a rate responsive pacemaker, an activity sensor mounted within the hermetically sealed enclosure is electrically connected to the EEPROM and other operating circuitry.

Abstract: A method and apparatus are disclose for transdermal iontophoretic delivery of ionic species, such as a drug in ionic form, in which therapeutic, electrical pulses having controlled, distinctive, dual-segment waveform characteristics are applied which facilitate more efficient drug administration throughout each pulse. The therapeutic pulses are generated at a predetermined frequency and have a predetermined pulse width. A first pulse segment and a second pulse segment comprise each dual-segment, therapeutic pulse. The electrical attributes of each pulse segment, including amplitude and duration, are controlled to produce the desired, pulsed output waveform.

Abstract: Pacer lead current is assessed by monitoring the current through one of a plurality of output stage transistors.