Abstract: A method of determining information concerning the identity of an individual comprising measuring at least one biometric of the individual comprising at least one bio-potential waveform generated by the individual's heart, extracting a plurality of characteristics from the bio-potential waveform comprising any of an approximate location of a point of a P peak, an approximate location of a Q-point of a QRS peak system, an approximate location of an R-point of a QRS peak system, an approximate location of an S-point of a QRS peak system, an approximate location of a point of a T peak, using the characteristics to calculate at least one waveform parameter, comparing at least one calculated waveform parameter with at least one previously-acquired waveform parameter to generate a score, and using the score to determine information concerning the identity of the individual.

Abstract: A single-use battery-powered external defibrillator comprises a sealed defibrillator housing 10 containing a battery-powered defibrillator circuit and a pair of defibrillator electrodes 14 permanently attached by leads 22 to the circuit within the housing.

Abstract: An H-bridge switching circuit for an automated external defibrillator comprises an SCR (D8) in one of the high legs of the circuit and a control means (D1-D7) associated with the SCR which is operative to switch the SCR on automatically in response to a voltage change across the SCR corresponding to the switching device in the diagonally opposite leg of the H-bridge turning on. The control means comprises a capacitor (D1) and the voltage on the capacitor changes when the diagonally opposite switching device turns on, the change in capacitor voltage lagging the change in voltage across the SCR and the SCR being turned on when the difference between the capacitor voltage and the voltage across the SCR exceeds a predetermined threshold.

Abstract: A flexible biomedical surface electrode comprises an insulating substrate (10), a conductive electrode layer (12) screen-printed on the substrate, and an insulating masking layer (14) on the electrode layer. The masking layer is configured to expose selected regions (16) of the electrode layer. An electrically conductive adhesive gel layer (18) on the masking layer makes electrical contact with the exposed regions of the electrode layer.

Abstract: A method of determining whether events in a heart's electrical activity result in corresponding blood flow events comprises simultaneously taking an electrocardiograph (ECG) and an impedance cardiograph (ICG) of the heart. Successive periods of the ECG are examined to detect successive occurrences of at least one periodic waveform feature indicative of electrical activity of the heart (14), and a period of time (search period) is defined following each such detection. The ICG is examined in each search period to detect the occurrence of a waveform feature (16) indicative of blood flow resulting from the detected occurrence in the ECG, and a signal is generated indicative of the degree of concordance (20) of the ICG with the ECG as a function of measurements made in respect of said detected waveform features.

Abstract: A sealed medical electrode package comprises first and second electrodes each comprising a conductive layer (14) disposed on one major surface of a flexible nonconductive backing sheet (10). The electrodes are disposed with their conductive layers (14) face-to-face and their backing sheets separably sealed together around their peripheral edges so that the backing sheets form a substantially gas-impermeable enclosure containing the conductive layers. In an alternative embodiment (FIG. 6) a respective electrical contact extends through each backing sheet into electrical contact with the respective conductive layer, and a substantially gas-impermeable packaging material encloses the electrodes. The packaging material has a respective aperture exposing each electrical contact, the periphery of each aperture being sealed to the backing sheet around the respective contact.

Abstract: A defibrillator connected by catheters (7) to the heart (6) has an external circuit (2, 12) connected to a passive implanted circuit (5) by transdermal induction via voils (3, 4). For atrial defibrillation, pulses of 3–4 J can be transmitted at about 7 MHz without damage, using an implanted coil (4) of 20 mm diameter.

Abstract: A defribrillator comprises first and second electrodes (A, B) for application to a patient, a voltage source (60), and an output circuit for connecting the voltage source across the electrodes upon the occurrence of a control signal (64). The output circuit includes a first current path connecting one side of the voltage source to the first electrode (A) and a second current path connecting the other side of the voltage source to the second electrode (B). Each of the current paths contains at least one solid state switching device USD1 (bo) or IGBT1. The switching device(s) USD1 (bo) in at least one of the current paths has no external control and characteristics similar to a Shockley diode.

Abstract: A system for determining the condition of a patient's heart comprises a plurality of electrodes for producing cardiac signals and means for converting the cardiac signals into digital form. Data processing means is programmed to process the digital cardiac signals to determine a plurality of parameters of the patient's heartbeat and determine the condition of the patient's heart using a binary decision tree algorithm. The algorithm has a plurality of decision nodes each of which makes a decision based upon the value(s) of a subset of the parameters, the decision criterion of at least one of the said decision nodes being modified according to the value of at least one parameter not of the subset. In addition, at at least one node, the respective subset of parameters may be determined according to the value of at least one parameter not of the subset.

Abstract: An apparatus for body surface mapping comprises a plurality of electrodes for attachment to spatially separate locations on a human torso with each electrode capable of detecting the electrical activity associated with a heartbeat and producing a corresponding voltage. The electrodes are sampled at a rate of 1 KHz during a cardiac cycle and sets of sampled values are produced and stored. Positional variations of the maximum and minimum sampled values over time are displayed as a projection of trajectories of the maximum and minimum sampled values in a three dimensional (x, y, t) space onto planes perpendicular to a plane containing the electrodes.

Abstract: An apparatus for coating a substrate with a diamond like coating or other vacuum depositable material comprises a chamber 11 having, or acting as, an anode, means for supporting a substrate 15 in the chamber, means for establishing a low pressure atmosphere containing a hydrocarbon-based gas in the chamber, and a radio frequency source 12 for establishing a gas plasma in the chamber, the substrate 15 acting as a cathode.

Abstract: A method of using body surface mapping to determine the condition of a human heart comprises attaching a plurality of electrodes to spatially separate locations on a human torso, each electrode being capable of detecting the electrical activity associated with a heartbeat and producing a corresponding signal. The signals are processed to calculate and present to the user QRS, ST-T and ST60 map vectors and related cardiac vectors. The condition of the human heart is determined by comparing the cardiac vectors derived from the ST-T and ST60 map vectors with the cardiac vector derived from the QRS map vector.

Abstract: An apparatus for body surface mapping comprises a plurality of electrodes for attachment to spatially separate locations on a human torso with each electrode capable of detecting the electrical activity associated with a heartbeat and producing a corresponding voltage. The electrodes are sampled at a rate of 1 KHz during a cardiac cycle and sets of sampled values are produced and stored. Positional variations of the maximum and minimum sampled values over time are displayed as a projection of trajectories of the maximum and minimum sampled values in a three dimensions (x, y, t) space onto planes perpendicular to a plane containing the electrodes.

Abstract: A system for determining the condition of a patient's heart comprises a plurality of electrodes for producing cardiac signals and means for converting the cardiac signals into digital form. Data processing means is programmed to process the digital cardiac signals to detemine a plurality of parameters of the patient's heartbeat and determine the condition of the patient's heart using a binary decision tree algorithm. The algorithm has a plurality of decision nodes each of which makes a decision based upon the value(s) of a subset of the parameters, the decision criterion of at least one of the said decision nodes being modified according to the value of at least one parameter not of the subset. In addition, at at least one node, the respective subset of parameters may be determined according to the value of at least one parameter not of the subset.

Abstract: An apparatus for coating a substrate with a diamond like coating or other vacuum depositable material comprises a chamber 11 having, or acting as, an anode, means for supporting a substrate 15 in the chamber, means for establishing a low pressure atmosphere containing a hydrocarbon-based gas in the chamber, and a radio frequency source 12 for establishing a gas plasma in the chamber, the substrate 15 acting as a cathode.

Abstract: A method of using body surface mapping to determine the condition of a human heart comprises attaching a plurality of electrodes to spatially separate locations on a human torso, each electrode being capable of detecting the electrical activity associated with a heartbeat and producing a corresponding signal. The signals are processed to calculate and present to the user QRS, ST-T and ST60 map vectors and related cardiac vectors. The condition of the human heart is determined by comparing the cardiac vectors derived from the ST-T and ST60 map vectors with the cardiac vector derived from the QRS map vector.

Abstract: A sensor device for monitoring bioelectric data from the thoracic region of a human body and/or for inducing stimulating signals to said region comprises a plurality of finger-like substrate portions of a flexible dielectric material. The substrate portions are releasably attachable to the thoracic region of a human body and the lateral spacing between the substrate portions is adjustable in accordance with the physiology of the body. A plurality of electrodes are provided on each substrate portion each having a respective lead connectable to an apparatus for inducing stimulating signals to, and/or receiving physiological signals from the electrodes. Indicia or other positioning elements are provided on at least one substrate portion for indicating the correct position of the assembly in use.

Abstract: A biosignal electrode device comprises a flexible electrically insulating substrate 11 having deposited thereon an electrically conductive layer forming an electrode sensor 14 and a lead 15 for the sensor. The portion of the substrate bearing the sensor is formed in relief such that the sensor stands above the surrounding substrate.

Abstract: A biomedical electrode device comprises an electrically insulating substrate carrying an electrode. The electrode is coated with a moisture-activated electrically conductive bioadhesive layer having an adhesion of between 50 and 500 g/cm.sup.2 and a water content of less than 25% w/w.