Abstract: An implantable defibrillation/cardioversion system and method comprising an electrode having a plurality of discrete electrically conductive segments. The conductive segments are electrically isolated from each other and electrically connected to a defibrillation/cardioversion unit. An electrical pulse block is generated and chopped into a plurality of discrete pulse segments by the defibrillation/cardioversion unit and applied to the electrode so that each conductive segment receives a particular electrical pulse assigned from the series of pulses. In this way, the concentration of gas generated from ionic current produced by a high energy defibrillation pulse is reduces and more energy is delivered to the heart, thus reducing the required energy input to the electrode. The electrode may be planar or in a catheter electrode configuration.

Abstract: An externally controlled implantable electronic device for delivering a cardioverting pulse of energy to an ailing heart. A defibrillator produces a first signal when its storage device is fully charged and ready to be discharged, and a second signal when a predetermined characteristic of an ECG signal is detected. An actuator is provided for determining the presence of both of these signals. If during a predetermined time period, there is a simultaneous occurrence of the first and second signals, then the defibrillator will be activated to deliver the cardioverting shock to the heart. In the absence of either of the two signals, the defibrillator will not deliver a shock.

Abstract: An implantable heart stimulator and related method calls for the determination of a given heart condition from among a plurality of conditions, the selection of at least one mode of operation for treating the determined condition, and the execution of the mode of operation selected, so as to treat the determined condition. In one embodiment of the invention, wherein a plurality of modes of operation for treating the various conditions are provided, the implantable heart stimulator includes processors, each processor being designed to efficiently execute a respective group of modes of operation. A further embodiment of the present invention calls for the implantable heart stimulator to be implemented by at least one programmable microprocessor. A still further embodiment calls for the provision of a data input/output channel, by means of which data can be provided to and retrieved from the implantable heart stimulator.

Abstract: An externally controlled implantable electronic device for delivering a cardioverting pulse of energy to the atrium of an ailing heart. In one embodiment, the device is particularly suited for use when the patient visits the office of his physician, and contemplates the transmission of both information and powering energy through the skin of the patient. In another embodiment, the device can be readily operated at home, by the patient, and without the intervention of the physician. Here, the source of energy is permanently implanted.

Abstract: Disclosed is a method and an apparatus for monitoring heart activity, for indicating or detecting abnormalities in such activity, and for taking corrective measures to return an arrhythmic heart to normal sinus rhythm. In one embodiment, monitoring and detecting are accomplished by developing a probability density function from ECG signals, or by sampling at least two portions of a probability density function. In another embodiment, a phase lock loop circuit is utilized to indicate fibrillation by the loop's inability to lock onto R--R interval signals. And in still another embodiment, cardiac electrodes are used to sense pulsatile impedance changes, absent in the presence of fibrillation. Also disclosed is a two-stage detector whose second stage is brought out of a stand-by state only after an arrhythmic condition is indicated by the first stage.

Abstract: Disclosed are two embodiments of a circuit for analyzing the ECG signals of a heart and for delivering a cardioverting pulse of energy to the heart if the heart is in an arrhythmic state in need of cardioversion. In the first embodiment, the ECG is filtered by a high pass filter to provide the derivative of the ECG, is reviewed by a window detector to determine the average time that the input ECG spends at high slope, and then the average occurrence of high slope segments is compared with a predetermined reference to determine whether the ECG is normal. Cardioversion is effected if the ECG is abnormal. In the second embodiment, an absolute value circuit and a level comparator is used in place of the window detector. The input ECG is normalized by an automatic gain control where the AGC voltage is derived from the ECG signals after high pass filtration.

Abstract: Disclosed are several embodiments of an electrode system for ventricular defibrillation, and the methods of using and implanting the electrode system. In one embodiment, the electrodes are in a generally base-apex configuration having a split conformal base electrode residing above the base of the ventricles (a transecting plane separating the atria from the ventricles) in the region of the atria and a conformal apex electrode in the form of a rotated conic section residing at the apex of the heart. In another embodiment, defibrillation is accomplished by the apex electrode acting against a catheter electrode situated high in the heart or in the superior vena cava.The electrodes themselves are in the form of planar metallic mesh elements adapted to lie in contact with body tissue on an active surface, insulated on the opposite surface. In another embodiment, the conductive portions of the respective electrodes are developed from metallic plates, exposed on one surface and insulated on the other.

Abstract: An externally controlled implantable electronic device for delivering a cardioverting pulse of energy to the atrium of an ailing heart. In one embodiment, the device is particularly suited for use when the patient visits the office of his physician, and contemplates the transmission of both information and powering energy through the skin of the patient. In another embodiment, the device can be readily operated at home, by the patient, and without the intervention of the physician. Here, the source of energy is permanently implanted.

Abstract: Apparatus and method for either manually or automatically initiating the cardioversion of a malfunctioning heart. The apparatus includes a single intravascular catheter electrode system which allows for a much more compact cardioverting system capable of being completely implanted within the patient. The heart function is continuously monitored, and when the function becomes abnormal, the malfunctioning heart is shocked by a voltage of sufficient amplitude to restore the heart to normalcy. If the heart does not return to its normal functions after a given interval, then it is again shocked. Normal heart activity ensures that the shocking mechanism remains inert.

Abstract: Pulse generating apparatus which provides electrical heart-stimulating pulses only in the absence of normal heart activity. If the patient's heart has developed a life threatening arrhythmic condition the inventive apparatus automatically applies an electrical shock to the heart having sufficient magnitude to restore normal heart activity. The inventive apparatus features a redundant heartbeat sensing system which monitors two dynamic characteristics of heart function, for example, heart contraction and EKG. An electrical heart stimulating pulse is delivered to the patient's heart following the elapse of a specified period of time since the sensing of a dynamic characteristic indicative of a normal functional heart. Sensing control is automatically regained following successful heart stimulation, thereby inhibiting the application of further electrical pulses.