Abstract: An electrosurgical dispersive electrode is disclosed that is useful in conjunction with an electrosurgical unit to establish capacitive-coupling with the skin of a patient receiving therapeutic signals from the electrosurgical unit. The electrode includes a metallic plate electrically connectable with the electrosurgical unit to establish a return current path thereto, an insulator engaging the inner (patient) side of the metallic plate to prevent ohmic contact by the plate with the skin of the patient, and a conductive adhesive gel at the outer (patient) side of the insulator so as to be positioned between the insulator and the skin of a patient to bring the skin uniformly in contact with the gel conductor and thereby reduce the impedance, normally associated with capacitively-coupled dispersive electrodes, while retaining uniform temperature distribution.

Abstract: Method of and apparatus for automatic defibrillation of the cardiac ventricles of a heart wherein both the mechanical and electrical activities of the ventricles are sensed and used as operating inputs to the controls. Electrical activity is detected and measured with a pair of electrodes, and the waves of an electrocardiogram (ECG) are analyzed. When such electrical analysis indicates that ventricular fibrillation is present and persists, an electrical circuit is actuated for detecting mechanical pumping activity of the heart. Mechanical pumping activity is measured by the change in impedance between the pair of electrodes in one of the ventricles. The change of ventricular impedance is caused by the varying volume of blood contained within the ventricle and depends upon whether the ventricle is in a contracted or a relaxed state. The defibrillator is actuated only when both the mechanical and electrical activity of the ventricle indicates a need for defibrillation.

Abstract: A demultiplexing method and system is disclosed utilizing a differential duration technique. Data that have been conventionally encoded utilizing a technique wherein variations in time contain the essential information, such as can be accomplished by systems wherein data are encoded by modulating either the spacing between pulses or the width of the pulses, is decoded by differential duration demultiplexing to reduce errors caused by time distortion introduced prior to recovery of the data. Time distortion errors are reduced by sensing both the pulses and intervals following the pulses in the data train and deriving decoded data from the difference therebetween.