Abstract: A defibrillator patient circuit including a capacitor having a two terminals; a first relay having a common terminal, and two contact terminals, where the first relay's common terminal is connected to the capacitor's first terminal; a charger circuit having two terminals, where the charger circuit's first terminal is connected to the first relay's first contact terminal and where the charger circuit's second terminal is connected to the capacitor's second terminal; a second relay having a common terminal, and two contact terminals, where the relay's second contact terminal is connected to the capacitor's second terminal; a first defibrillation contact connected to the second relay's common terminal; a second defibrillation contact connected to the first relay's second switch contact; and an inductor connected in series with the capacitor, the two relays, and the two defibrillation contacts.

Abstract: A multiple sensor cardiac pacemaker blends the outputs from a fast-reacting Activity sensor and a slower-reacting Minute Ventilation sensor to achieve an optimally desirable pacing rate. The pacemaker conserves battery energy by forcing the Minute Ventilation sensor output to be at its minimum value by disabling the Minute Ventilation algorithm for a predetermined time period when the Activity sensor is at its minimum observed value. Power is conserved because the Minute Ventilation sensor and associated algorithms which normally consume power to operate the circuitry, and to measure impedance are disabled temporarily only during selected periods where the Activity sensor is at its minimum observed value, thereby maintaining optimal blending of the pacemaker sensor outputs in achieving the desired pacing rates.

Abstract: An ambulatory (in the home) patient health monitoring system is disclosed wherein the patient is monitored by a health care worker at a central station, while the patient is at a remote location. The patient may be a person having a specific medical condition monitored or may be an elderly person desiring general medical surveillance in the home environment. Cameras are provided at the patient's remote location and at the central station such that the patient and the health care worker are in interactive visual and audio communication. A communications network such as an interactive cable television is used for this purpose. Various medical condition sensing and monitoring equipment are placed in the patient's home, depending on the particular medical needs of the patient. The patient's medical condition is measured or sensed in the home and the resulting data is transmitted to the central station for analysis and display.

Abstract: The present invention provides a system and method for characterizing cardiac fibrillation using wavelet transforms. By characterizing the seriousness of a fibrillation episode, a defibrillation shock may be delivered to the heart with less excess energy than conventional ICDs. A wavelet transform is performed on a digitized ECG using a second derivative weight function and the results are analyzed for missing "peaks" in the data. The more serious the fibrillation, the more peaks will be missing from the data. This information may then used to modify the voltage of the defibrillation shocks as a function of the seriousness of the fibrillation.

Abstract: A practical and effective prophylactic implantable cardioverter defibrillator (ICD) that has the potential to benefit a large number of patients with less severe cardiac conditions who now lack the opportunity to be served in a practical way by existing ICD systems. Unlike existing ICD systems, the prophylactic ICD is designed to deliver between about 100 to 200 shocks, with each shock having a maximum delivered energy value of only about 25 joules. As a result, the initial stored energy requirements of the prophylactic ICD system are less than about 12,000 joules, and both the battery and the capacitor systems can be significantly smaller than existing ICD system. The smaller battery and capacitor systems produce in an implantable device having a physical size small enough to permit implantation of the device in the pectoral region.

Abstract: An implantable defibrillator has a charging circuit which charges a capacitance, electrodes for delivering energy from the capacitance to a heart, and a switching stage for discharging the capacitance through the electrodes and across heart tissue to defibrillate the heart, as needed. A non-inductive current limiter is connected in vivo in the discharge path for limiting the current supplied to the heart tissue to predetermined maximum value.

Abstract: A group of muscles, particularly the glutei, is stimulated electrically by the application of at least one pair of electrodes (18, 19; 20, 21) to the group and the supply of a symmetrically alternating voltage through the electrodes for equal periods of time (A) separated by intervals (B) of predetermined equal duration. In each period of time (A), the alternating voltage has a periodic behaviour with pulses of equal duration (PD) and alternating polarity symmetrical in adjacent half periods and separated by intervals (I) of equal duration. Each period (A) in which the alternating voltage is applied has a duration of between 0.5 and 1.5 s, and the intervals between the periods (A) are between 0.8 and 2 s long. The frequency of the alternating voltage is between 100 and 200 Hz, preferably 150 Hz. Each half period (T/2) in which the voltage is applied includes a pulse having a duration (PD) of between 40 and 60% of the half period.

Abstract: An implantable cardioverter/defibrillator has an electrode system including two electrodes, at least one of the two electrodes being adapted for placement in a peripheral vein of the heart, the peripheral veins constituting the venous side of the coronary vessels running between the base of the heart and the apex of the heart.

Abstract: For detecting tachyarrhythmia of the heart, the partial pressure of gases physically dissolved in the blood is measured, preferably the partial oxygen pressure pO.sub.2, and a fast variation and/or a variation of the measured partial pressure pO.sub.2 that exceeds a prescribed degree is utilized as a criterion for the detection of a tachyarrhythmia. An apparatus for treating tachyarrhythmia of the heart operating according to the above method includes a sensor for identifying the partial pressure of gases dissolved in the blood, an evaluation unit supplied with the sensor output for recognizing rapid changes of the partial pressure or changes of the partial pressure that exceed a prescribed degree, the output of the evaluation unit being connected to circuitry for triggering the tachyarrhythmia treatment.

Abstract: A bio-operated implant system for implantation inside a human body. A piezoelectric generator in the form of a flexible sheet of poled polyvinylidene fluoride structurally that is attached in surface-to-surface contiguity with a skeletal number, which flexes with negligible elongation of its surface, is connected in circuit with a power consuming device such as a pacemaker, to a rectifier, and to a power storage device such as a condenser or battery. The generator generates in alternating voltage, which is rectified to direct current, which is supplied to the power consuming device on demand.

Abstract: A method and apparatus for testing the integrity of biphasic and monophasic defibrillator switches in an implantable defibrillator without delivering a shock to the patient. The test circuitry is integrated with and implantable with the defibrillator and provides for the testing of the defibrillator switches without shocking the patient by charging the capacitive defibrillation voltage source to a predetermined level and discharging it through a resistive network and shunting one of the switches to provide an alternate current path to ground, while isolating the test circuitry from the patient. Switch conditions are capable of ascertainment by measuring residual charge, i.e., voltage, on the capacitive voltage source at selected measurement times.

Abstract: A lead, for use in combination with an implanted pulse generator which may be a pacemaker or defibrillator or combination thereof. The lead can deliver an electrical charge to pace, cardiovert or defibrillate the heart, and can sense cardiac activity in the heart. The lead may include additional sensor electrodes capable of sensing electrical or physical activity in the atrial cavity. The lead allows cardioversion and/or defibrillation stimuli to be provided by a large surface area electrode which is passively implanted in the ventricle, to allow the pulse generator to provide appropriately synchronized atrial-ventricular pacing, cardioversion or defibrillation.

Abstract: An implantable cardiac defibrillator system, comprising:a) a charge storage element,b) a switching element connected to the charge storage element,c) a processor capable of detecting a defibrillation event in a patient,d) patient connection electrodes connected to the switching element and to the processor,e) a cardiac impedance monitoring section connected to the patient connection electrodes, andf) a charge storage element discharge section communicatively connected to the switching element.

Abstract: An implantable heart defibrillator is equipped with at least one intracardiac defibrillation electrode. A post-therapy apparatus is arranged to emit, after a defibrillation pulse, at least one stimulation pulse through the defibrillation electrode, the stimulation pulse having energy far higher than the energy in a normal heart stimulation pulse for cardiac pacing, but less energy than a normal defibrillation pulse.

Abstract: A rotatable pin, screw-in pacemaker lead assembly has a conductor coil enclosed within a silicone insulating tube. The conductor coil has a distal end secured to a helix electrode and a proximal end including a rotatable connector pin. The outer surface area of the conductor coil is coated with a super thin film of biocompatible Teflon. The Teflon coating substantially reduces the friction between the conductor coil and the inner wall of the insulating tube during lead fixation, thereby substantially reducing the number of turns of the connector pin required to effect fixation of the helix electrode.

Abstract: Systems for ablating tissue control radiofrequency power to an ablation electrode by relying upon actual phase sensitive power measurements, unaffected by phase shifts between radiofrequency voltage and current. The systems also detect these phase differences, if they develop, and integrate this factor in making their control decisions.

Abstract: A programmable offset is added to an automatically generated baseline reference value to provide a Threshold value used by the rate-responsive sensor processing circuits of an implantable rate-responsive pacemaker to determine the significance of a sensor input signal. The rate-responsive pacemaker provides stimulation pulses on demand at a pacing rate determined by a sensed physiological parameter. The physiological parameter is sensed by a physiological sensor included within, or coupled to, the rate-responsive pacemaker. The physiological sensor generates a sensor input signal having a magnitude that varies as a function of the sensed physiological parameter. The invention provides a way for the rate-responsive pacemaker, when operating in an autothreshold mode, to automatically determine when the magnitude of the sensor input signal is sufficiently large to justify an increase in the pacing rate.

Abstract: An electrosurgical control for a trocar has a trocar with a cannula with a stylet coaxially fit therein. The stylet is movable relative to the cannula along a common axis. The trocar is shaped for insertion in a direction generally along the axis through tissue in a puncture procedure with its stylet. A distal end and a proximal end on the elongate cannula so the distal end enters the tissue while the proximal end remains outside. A tip on the stylet end, near the distal end of the cannula, normally extends therebeyond in position to puncture the tissue. The stylet has an energy supply passing from the tip to its opposite end and moves reciprocally relative to the cannula so the tip extends or is fully within the cannula. An electrosurgical generator provides energy to the opposite end of the stylet and an electrosurgically active device is a part of the tip and connects to the energy supply.

Abstract: A cardiac pacemaker having an automatic pulse rate response gain factor responsive to at least one cardiac-related physiological characteristic of a patient. The pacemaker includes a rate controller that comprises a detector for detecting a plurality of individual measurements of at least one physiological characteristic over each of a plurality of pre-determined time periods, with each of the individual measurements being an average of values detected over each of a respective multiple number of incremental time periods occurring within each of the pre-determined time periods. The pacemaker saves the highest measurement from one incremental time period of each of several consecutive pre-determined time periods, and these highest measurements are averaged. Thereafter, the rate controller adjusts the rate response gain factor or slope of the pulse rate in relation to the physiological characteristic measurement and a pre-determined target pulse rate.

Abstract: A medical electrical lead of the type which includes an electrode at a distal end of the lead a connector at a proximal end of the lead and an elongated electrical conductor extending between the electrode and the connector. The conductor is comprised of a wire wound in a coil configuration with the wire comprised of a duplex titanium alloy. Materials of such composition have been found to have suitable conductivity for use with implantable pulse generators and suitable fatigue strength when used in endocardial lead placement. Moreover, such materials have been found to pass tests intended to detect metal ion oxidation (MIO) in susceptible polymeric materials.