Abstract: A method and apparatus for enhancing the integrity of an implantable sensor. Voids formed between an outer tubing and a sensor substrate or spacing element may be back-filled with a curable, implantable material, minimizing the extent to which unwanted fluids diffuse within the sensor. An enzyme or protein matrix pellet below the sensor window may be pre-treated with a reducing agent to enhance its bond stability, and to reduce undesired swelling that may cause the sensor window to detach or leak. The bonding between the enzyme pellet and a hydrogel layer may be reinforced by application of an intervening bonding layer of a protein material, such as human serum albumin (HSA). The size of the window may be minimized by minimizing the size of an underlying electrode, providing reduced flux and lengthening sensor. A coating may be deposited on the surface of the sensor leads, providing stiffening and lubrication.

Abstract: A catheter introduction apparatus provides an optical assembly for emission of laser light energy. In one application, the catheter and the optical assembly are introduced percutaneously, and transseptally advanced to the ostium of a pulmonary vein. An anchoring balloon is expanded to position a mirror near the ostium of the pulmonary vein, such that light energy is reflected and directed circumferentially around the ostium of the pulmonary vein when a laser light source is energized. A circumferential ablation lesion is thereby produced, which effectively blocks electrical propagation between the pulmonary vein and the left atrium.

Abstract: An apparatus and method is presented for improving cardiac function after successful termination of a tachyarrhythmia such as ventricular fibrillation. A series of electrical stimulation pulses are delivered prior to a defibrillation shock if one or more specific criteria are met.

Abstract: An electrotherapy device including at least one sensor operable to sense at least one physiological parameter of a patient. A controller is operably connected to the at least one sensor operable to receive signals from the at least one sensor corresponding to the at least one physiological parameter. Memory is operable to store computer-programming code executed by the controller. The programming code includes decision-making criteria operable to adapt a patient treatment in response changes to the detected at least one physiological parameter. At least one pair of electrodes is operably connected to the controller and operable to administer the treatment to the patient.

Abstract: Medical device data is transferred using a universal adaptor between an implanted medical device and hospital monitoring systems. The universal adaptor is an interface compatible with various built-in hospital monitoring network comprised of equipment from a variety of manufacturers. The universal adaptor includes a telemetry circuitry, a calibration system for atmospheric pressure and an analog interface. The calibration system relates to barometric correction and includes an external pressure reference system.

Abstract: A medical device constructed according to the invention includes electrodes (12a, 12b), a measuring unit (24) for measuring a patient-dependent electrical parameter (e.g., impedance) of the patient, an electrotherapy generator (26) for delivering electrotherapy to the patient, and a processing unit (20) for controlling the delivery of electrotherapy to the patient. Electrotherapy is preferably delivered to the patient based on the measured patient-dependent electrical parameter and a predetermined response of a reference patient to a nominal electrotherapy. The actual electrotherapy delivered to the patient is controlled so that the electrotherapy has a probability of success for the patient that is equivalent to the probability of success of the nominal electrotherapy for the reference patient. A consistent shock efficacy across different patients is achieved.

Abstract: A system and method for long-term monitoring of cardiac conditions such as arrhythmias is disclosed. The invention includes a pulse generator including means for sensing an arrhythmia. The pulse generator is coupled to at least one subcutaneous electrode or electrode array for providing electrical stimulation such as cardioversion/defibrillation shocks and/or pacing pulses. The electrical stimulation may be provided between multiple subcutaneous electrodes, or between one or more such electrodes and the housing of the pulse generator. In one embodiment, the pulse generator includes one or more electrodes that are isolated from the can. These electrodes may be used to sense cardiac signals.

Abstract: A system and method for use in an implantable cardiac device permits the monitoring of progression and regression in heart disease, such as congestive heart failure. During a monitoring period, a sensing circuit produces an electrogram signal of the patient's heart and a sound sensor produces a phonocardiogram of the patient's heart. A processor determines a predetermined characteristic of the heart sounds, such as amplitude, time intervals between selected heart sounds, and time intervals between selected heart sound and selected electrogram features for each cardiac cycle occurring during a monitoring period. The predetermined characteristics are thereafter averaged and stored in a memory for later retrieval. Relative changes in the average time intervals over time provides an indication of the progression or regression of the heart disease.

Abstract: A heart-synchronized pulsed laser system includes a laser; means for sensing the contraction and expansion of a beating heart to be synchronized with the laser; means, responsive to the means for sensing, for generating a trigger pulse; means for positioning the leading edge of the trigger pulse; means for positioning the leading edge of the trigger pulse during the contraction and expansion cycle of the heartbeat; means for defining the width of the trigger pulse to occur during the heartbeat cycle; and means responsive to the trigger pulse for firing the laser to strike the beating heart at the time indicated by the trigger pulse position and for the period indicated by the width of the trigger pulse.

Abstract: A system and method includes a cardiac resuscitation apparatus connected to an automated external programmable defibrillator (AED) or a semi-automated external programmable defibrillator (SAED) includes an adhesive Doppler pad to detect a pulse signal of a patient. Defibrillation-monitoring pads are connected to the Doppler pad and detect an ECG signal of the patient. A processor integrates the pulse signal and the ECG signal to determine therefrom whether or not shock therapy is advised for the patient.

Abstract: ECG recording apparatus 1 includes a port 2 for connection to ECG electrodes and a microphone 3 for detecting vocal signals, Processing electronics store a recording of the vocal signals and the physiological data on the storage medium 4.

Abstract: A method of reducing the likelihood of pulseless electrical activity (PEA) after defibrillation in a subject comprises administering to a subject afflicted with fibrillation a first treatment waveform, the first treatment waveform insufficient to defibrillate the heart; and then administering to the subject a second treatment waveform that defibrillates the heart and restores organized electrical activity in the heart. The first treatment waveform reduces the likelihood of onset of PEA following the second treatment waveform, as compared to that likelihood which would be present in the absence of the first treatment waveform.

Abstract: A capture-detection cardiac pacemaker wherein a stimulation success can be reliably detected immediately after stimulation pulse output. The cardiac pacemaker according to this invention generally includes at least one stimulation electrode arranged in the region of the heart designed to output stimulation pulses to the heart, and a control unit connected to a pulse generator for controlling the stimulation pulse output. The control unit is connected to a sensor arranged at the myocardium for checking stimulation success at the heart by detecting the myocardial impedance pattern immediately after a stimulation pulse output and still within the diastolic phase of the heart, and controlling the stimulation pulse output based thereon.

Abstract: An implantable medical device system for detecting cardiac conditions such the long-term ischemic heart disease, an occlusion of a coronary artery by a thrombus or an impending as a myocardial infarction. The implantable medical device (IMD) system includes a sensor that outputs a blood flow rate signal representing a rate of blood flow through a coronary sinus of a patient's heart. An implantable medical device (IMD) includes a microcomputer circuit configured to analyze the blood flow rate signal and detect a cardiac condition as a function of the blood flow rate signal. The system can also includes an implantable lead that senses electrical activity from the patient's heart. The microcomputer circuit monitors an ST segment of the electrical activity signal and detects a cardiac condition as a function of blood flow rate signal in conjunction with the electrical activity signal.

Abstract: A method and apparatus determines the presence of a cardiac pulse in a patient by evaluating a physiological signal in the patient, preferably for the presence of characteristic heart sounds. The presence of a heart sound in a patient is determined by analyzing phonocardiogram (PCG) data obtained from the patient. Analyzing the PCG data may include evaluating temporal energy in the PCG data or evaluating spectral energy in the PCG data. Evaluating temporal energy in the PCG data may include estimating a first and second energy in the PCG data and comparing the first and second energy to determine a relative change in energy between them. Evaluating spectral energy in the PCG data may include calculating an energy spectrum of the PCG data and evaluating either the energy value or the frequency of a peak energy in the energy spectrum. The presence of a heart sound may also be determined by combining an evaluation of temporal energy with an evaluation of spectral energy in the PCG data.

Abstract: A steerable, direct myocardial revascularization catheter comprises a catheter body, a control handle, a tip section, and a means for deflecting the tip section by manipulation of the control handle. The catheter body has an outer wall, proximal and distal ends and at least one lumen extending therethrough. The control handle is situated at the proximal end of the catheter body. The tip section comprises a flexible tubing having proximal and distal ends and at least one lumen therethrough. The proximal end of the tip section is fixedly attached to the distal end of the catheter body. The catheter also comprises an optic fiber having proximal and distal ends. The optic fiber extends through a lumen in a catheter body and tip section. The distal end of the optic fiber is substantially flush with the distal end of the tip section. The catheter further comprises an infusion tube having proximal and distal ends. The infusion tube extends through a lumen in the catheter body and tip section.

Abstract: A blood pump for assisting a heart is provided having a stator and a rotor. The rotor is magnetically radially supported creating a suspension gap between the stator and the rotor. The rotor can be supported axially by a Lorentz force bearing and can be magnetically rotated. The stator can have a single or double volute pump chamber and the rotor can have an impeller portion for pumping blood. The rotor can have a center bore as a primary blood flowpath. The suspension gap can be a secondary blood flowpath. The blood pump can also have an axial position controller and a flow rate controller. The axial position controller can cause the axial bearing to adjust the position of the rotor. The flow rate controller can have a member for measuring a dimension of a heart ventricle to control the flow rate to avoid overly distending or contracting the ventricle. A method of operating the flow rate controller to create a pulsatile flow rate is also provided.

Abstract: The instant invention provides an apparatus, and a method of its use, for enabling an instructor to train a student in learning a procedure which embodies at least two alternative sequences of steps and conditions. The invention, in order, enables the student to initiate the procedure; enables communication of at least one condition or an instruction required for prompting the student to initiate at least one step following in the sequence, at a time, to the student; enables the instructor to provide an alternative sequence; and, enables the student to initiate at least one step of said procedure in response to said alternative sequence.

Abstract: A cardiac rhythm management system includes a defibrillation lead impedance measurement system by which defibrillation lead impedance is measured using a test current source different from the defibrillation output supply. A resulting voltage is measured to determine the defibrillation lead impedance. Using low amplitude test currents (e.g., 10-20 milliamperes) avoids patient discomfort. Charge-balanced test currents avoids charge build-up that may interfere with sensing and avoids electrode degeneration. Different current amplitudes and resulting measured voltages provide a differential defibrillation lead impedance measurement for canceling undesired effects. Bidirectional test currents account for polarity effects on the defibrillation lead impedance measurement. A calibration/correction technique uses measurements of known resistances to correct a measurement of an unknown defibrillation lead impedance measurement.

Abstract: An apparatus and method for treating post-defibrillation electromechanical dissociation (“EMD”) or pulseless electrical activity (“PEA”). A first embodiment comprises an implantable defibrillator with the capability of detecting and treating post defibrillation EMD. The stimulator/defibrillator has one or more leads with electrodes and at least one electrode for defibrillation. A sense circuit senses the electrical condition of the heart of the patient. A second sensor senses a parameter correlated to the state of blood flow. The cardiac stimulator/defibrillator detects and terminates ventricular tachyarrhythmia or fibrillation. If the stimulator/defibrillator detects the presence of electrical rhythm in the heart correlated, however, with inadequate blood flow to sustain life (EMD), the device provides an output to stimulate the heart to overcome EMD. The device may also be an external defibrillator.

Abstract: In a method for locating a measurement and/or treatment catheter in a vessel or organ of a patient relative a fixed catheter, also positioned within the patient in the vicinity of the measurement and/or treatment catheter signals are transmitted from one of the catheters and received at the other one. The position and direction of the measurement and/or treatment catheter relative to the fixed catheter is then determined from the received signals. An arrangement for locating a measurement and/or treatment catheter, intended to be positioned in a vessel or organ of a patient, also includes a fixed catheter, also intended to be positioned within the patient in the vicinity of the measurement and/or treatment catheters. One of the catheters has a signal transmitter and the other one has a signal receiver for receiving signals from the signal transmitter. A signal processor determines from the received signals the position of the measurement and/or treatment catheter relative to the fixed catheter.

Abstract: An apparatus and method for treating post-defibrillation electromechanical dissociation (“EMD”). A first embodiment comprises an implantable defibrillator, which may include cardioversion and pacemaker capabilities, which has the capability of detecting and treating post defibrillation EMD. The stimulator/defibrillator has one or more leads with electrodes. At least one electrode for defibrillation may be an endocardial or epicardial electrode or other suitable defibrillation electrode. A sense circuit senses the electrical condition of the heart of the patient. A hemodynamic sensor senses a parameter correlated to the state of blood flow. The cardiac stimulator/defibrillator detects ventricular tachyarrhythmia including fibrillation and terminates ventricular tachyarrhythmia. After termination of the ventricular tachyarrhythmia, the stimulator/defibrillator can detect the presence of electrical rhythm in the heart correlated, however, with inadequate blood flow to sustain life.

Abstract: An implantable defibrillator apparatus having a plurality of defibrillation electrodes which can be applied to the heart muscle in order to apply electric defibrillation shocks thereto, and defibrillation-control means for selectively applying respective electric defibrillation shocks to the electrodes preferably sequentially in time and in synchronism with the QRS.

Abstract: A discharge resistor is thermally monitored under computer supervisory control. Current flow through the resistor is duty-cycle controlled to prevent thermal damage.

Abstract: A force sensor, for use in combination with an automated electronic defibrillator (AED), includes a first conductive layer. A second conductive layer is spaced apart from the first conductive layer such that no electrical communication occurs between the first and second conductive layers. An electrical communication device is provided for establishing electrical communication between the first and second conductive layers responsive to the application of a force to said electrical communication means.

Abstract: A resuscitation device for automatic compression of victim's chest using a compression belt which exerts force evenly over the entire thoracic cavity. The belt is constricted and relaxed through a motorized spool assembly which repeatedly tightens the belt and relaxes the belt to provide repeated and rapid chest compression. An assembly includes various resuscitation devices including chest compression devices, defibrillation devices, and airway management devices, along with communications devices and senses with initiate communications with emergency medical personnel automatically upon use of the device.

Abstract: A steerable direct myocardial revascularization catheter comprises a catheter body, a tip section and a control handle. The catheter body has an outer wall, proximal and distal ends and at least one lumen extending therethrough. The tip section comprises flexible tubing having proximal and distal ends and at least one lumen therethrough. The proximal end of the tip section is fixedly attached to the distal end of the catheter body. The control handle comprises a first member fixedly attached to the proximal end of the catheter body, a second member being movable relative to the first member, and a first guide tube extending through the control handle from the proximal end to the distal end of the control handle. The first guide tube is fixedly attached to one of the first or second members. The catheter also comprises an optic fiber having a distal end and a proximal end.

Abstract: A processing system and method are provided for deriving an improved hemodynamic indicator from cardiac wall acceleration signals. The cardiac wall acceleration signals are provided by a cardiac wall motion sensor that responds to cardiac mechanical activity. The cardiac wall acceleration signals are integrated over time to derive cardiac wall velocity signals, which are further integrated over time to derive cardiac wall displacement signals. The cardiac wall displacement signals correlate to known hemodynamic indicators, and are shown to be strongly suggestive of hemodynamic performance. An implantable cardiac stimulating device which uses cardiac wall displacement signals to detect and discriminate cardiac arrhythmias is also provided.

Abstract: An impedance monitor for discerning edema through evaluation of respiratory rate. Preferred embodiment includes edema monitor and trigger to initiate diagnostic reporting or corrective action when activated. Recording of Long Term Average and Short Term Average values for secondary edema measure based on DC signal level are described as are methods and apparatus for removing unwanted recurring noise.

Abstract: In an implantable pacemaker.backslash.cardioverter.backslash.defibrillator, a system for correlating the delivery of an atrial cardioversion therapy to an optimum blood pressure to effect delivery of the therapy when the volume of the atrium is minimized. In a first embodiment, the blood pressure in the atrium or ventricle is monitored and delivery is timed to a low blood pressure occurring as blood is emptying from the atrium. In a variation ventricular pacing may be provided to ensure that the ventricles are contracting forcefully and at a rate which optimizes atrial emptying. In a second embodiment, the delivery of the cardioversion therapy is also timed to an optimum point or phase of the respiratory cycle. The optimum point or phase of the respiration cycle depends in part on the chamber to be cardioverted and the location of the cardioversion electrodes with respect to the chamber.

Abstract: A method of generating and applying a defibrillation shock of the present invention includes first applying a defibrillation shock pulse to a patient with an initial predetermined amount of energy not based on a patient-dependent electrical parameter, and while monitoring a patient-dependent electrical parameter. Next, patient transthoracic impedance is determined based on the patient-dependent electrical parameter. Finally, a subsequent predetermined amount of energy is applied to the patient based on the patient transthoracic impedance calculated above and while monitoring the patient-dependent electrical parameter. Subsequent defibrillation shock pulses are applied using a patient impedance based on the patient-dependent electrical parameter observed during the most recent defibrillation shock. In this manner, an optimal combination of charged voltage and the maximum allowed current (under the AAMI defibrillation waveform standard) is applied for a patient's given transthoracic impedance.

Abstract: A method of indicating operational status of an electronic device, the device providing an indication of device operational status as a result of a self-test, the method including the following steps: monitoring an environmental condition; changing an indication of device operational status from a first indication to a second indication if the monitored environmental condition changes from a first condition to a second condition, this changing step being performed without performing a self-test. In certain embodiments, the monitored environmental condition is a monitored temperature, the first condition is a first temperature and the second condition is a second temperature. The electronic device may be battery-operated, in which case the self-test is a battery capacity test.

Abstract: An implantable anti-arrhythmia device such as a defibrillator or anti-tachycardia pacemaker with an associated patient activator. In response to the patient activation signal, the implanted device notifies the activator whether an atrial rhythm requiring treatment is present and whether a therapy is available for delivery in response to the patient's request. After the patient is notified that a therapy is pending, the implanted device charges its output capacitors and thereafter determines whether opportunities for prompt synchronization are present with a desired frequency, over a preceding series of depolarizations. If both conditions are met, the likelihood that a defibrillation or cardioversion pulse can be delivered quickly following a patient initiated retrigger signal is high, and the device notifies the patient's activator that it will await receipt of a patient retrigger signal, as a prerequisite for a delivery of the cardioversion or defibrillation pulse.

Abstract: In an implantable pacemaker/cardioverter/defibrillator, a system for correlating the delivery of a cardioversion therapy to an optimum point or phase of the respiratory cycle of the patient to effect delivery of the therapy when the impedance between the cardioversion electrodes is minimized. In a first application for use with cardioversion electrodes located substantially in contact with the heart chamber, the optimum point or phase is at the end of inspiration. In a second application for use with at least one cardioversion electrode located remotely from the heart chamber, the optimum point or phase is at end expiration or beginning of inspiration. The cardioversion therapy is delivered in synchrony with a ventricular sense event, if present. If the optimum point or phase of the respiratory cycle cannot be determined during a therapy time, a pre-shock may be delivered to elicit a respiration cycle through a stimulated contraction of the diaphragm.

Abstract: A method and apparatus for generating a multiphasic defibrillation/cardioversion waveform as well as a multiphasic fibrillation inducing pulse train. The multiphasic fibrillation inducing waveform being applied to the same electrodes as the defibrillation/cardioversion waveform.

Abstract: A medical therapy device includes at least one sensor for detecting a varle that can be measured on the body of a patient. An evaluating and control device is connected to the output of the sensor. A therapy device is connected to the output of the evaluating and control device and provides different therapies or therapy variables as a function of the value of the therapy control variable. A processing unit has an input connected to the output of a time controlled fluctuation-value generator which is connected between the output of the sensor and the input of the evaluating and control device.

Abstract: An implantable cardioverter for providing cardioversion electrical energy to at least one chamber of a patient's heart in need of cardioversion and applying a pain alleviating therapy at an appropriate site in the patient's body prior to or in conjunction with the delivery of the cardioversion energy to the heart chamber to alleviate propagated pain perceived by the patient. The combined cardioversion and pain alleviating therapies are preferably realized in a single implantable, multiprogrammable medical device or separate implantable cardioversion and pain control devices with means for communicating operating and status commands between the devices through the patient's body.

Abstract: An electrotherapy method and apparatus for delivering a multiphasic waveform from an energy source to a patient. The preferred embodiment of the method comprises the steps of charging the energy source to an initial level; discharging the energy source across the electrodes to deliver electrical energy to the patient in a multiphasic waveform; monitoring a patient-dependent electrical parameter during the discharging step; shaping the waveform of the delivered electrical energy based on a value of the monitored electrical parameter, wherein the relative duration of the phases of the multiphasic waveform is dependent on the value of the monitored electrical parameter.

Abstract: An implantable cardiac stimulator delivers a first electrical shock via implantable stimulating electrodes at a time when there is substantially no flow of blood. At least one of the stimulating electrodes is disposed in a blood flow path of the cardiovascular system. The first shock is of insufficient energy level to cause defibrillation. An electrical potential is measured as a function of time between the blood-contacting electrode and a reference electrode following delivery of the first shock to obtain a first potential equilibration function under no-flow conditions. A second therapeutic electrical shock, of sufficient energy level to effect defibrillation, is delivered via the stimulating electrodes. A second potential equilibration function is measured following delivery of the second shock. The first and second potential equilibration functions are compared, and if the two functions are sufficiently different in morphology, it is determined that blood is flowing.

Abstract: This invention provides an external defibrillator and defibrillation method that automatically compensates for patient-to-patient impedance differences in the delivery of electrotherapeutic pulses for defibrillation and cardioversion. In a preferred embodiment, the defibrillator has an energy source that may be discharged through electrodes on the patient to provide a biphasic voltage or current pulse. In one aspect of the invention, the first and second phase duration and initial first phase amplitude are predetermined values. In a second aspect of the invention, the duration of the first phase of the pulse may be extended if the amplitude of the first phase of the pulse fails to fall to a threshold value by the end of the predetermined first phase duration, as might occur with a high impedance patient.

Abstract: An apparatus and method for predicting the efficacy of cardioversion as a dality for reverting a patient with atrial fibrillation to normal sinus rhythm. Blood flow through the patient's atrium is measured, converted and processed using nonlinear or chaotic processing to obtain a differential radius signal. The number of excursions of the differential radius beyond a threshold value indicates whether cardioversion will be successful.

Abstract: A method and device for efficient defibrillation, to be utilized in external defibrillation machines, capable of being utilized with 2, 3, or more defibrillation electrodes. The method and device achieve the efficient defibrillation by ensuring that the defibrillation machine energizes the patient with the waveform which is optimum for the number of defibrillation electrodes in use. The method and device accomplishes this by (1) sensing the number of defibrillation electrodes in use, and by (2) selecting the optimum defibrillation waveform for energization of the sensed number of defibrillation electrodes in use.

Abstract: An implantable cardioverter defibrillator (ICD) system features rate-responsive pacing capabilities. An electrical pulse generating device having a housing containing pulse generating circuitry is provided. A conductive lead connectable to the housing that has a first electrode, a second electrode and a coil electrode is provided. Switching circuitry is provided contained in the housing that switches the coil electrode between the rate-responsive sensing electrode to a defibrillation electrode. Control circuity is provided within the housing for controlling the delivery of modulating signals to the coil electrode and for sensing changes in resistance between the coil electrode and the housing. The control circuitry also causes an alteration of the pacing signal applied to the pacing electrode depending upon the change in the resistance sensed.

Abstract: A package of defibrillator electrodes having a date indication element and a circuit for determining a date of manufacture of medical electrodes within the package is provided. Specifically, by the circuit and package design of the present invention, the presence of a fresh package of electrodes can be detected. A circuit detectable package of medical electrodes is provided including first and second electrodes within the package. An electrical interconnection means is provided between the first and second electrodes for electrically completing a circuit connecting the lead wire of the first electrode to the lead wire of the second electrode, and includes a date identification element which when subjected to an applied voltage by way of the lead wires generates a measurable affect representative of the manufacturing period of the defibrillator electrodes. The date identification element may comprise a passive element, a value of which represents a date and can be measured.

Abstract: The device senses Natural Heart Acceleration (NHA), isolating at least one segment (t) thereof corresponding to an isovolumetric phase, such as isovolumetric contraction (P1, P2) and/or isovolumetric relaxation (P3, P4). Preferentially, the action of isolation of the aforesaid segment is made starting from the electrocardiogram (ECG) signal. Among other things, the device may be used to carry out pacing functions (pacemaker, defibrillator, pacer cardioverter defibrillator) and/or to pick up, possibly by telemetry, data on the myocardial function and/or also to control a system of drug administration.

Abstract: A device for detecting a state of imminent cardiac arrhythmia, relative to a normal state for a heart, in response to activity in nerve signals conveying information from the autonomic nerve system to the heart, contains a sensor body for sensing neural activity, a comparator with a threshold value forming a condition for the presence of an arrhythmia, the comparator emitting an arrhythmia-indicating output signal depending on whether neural activity meets the condition, and the sensor body being placeable in an extracardiac position for at least one of the sympathetic and vagus nerves. The sensor body directly senses activity in the nerve at that location in direct contact with the nerve. An implanted blood pressure sensing cuff also can be provided which generates signals indicative of blood pressure which can be evaluated in combination with the nerve signals for identifying the state of imminent cardiac arrhythmia.

Abstract: An automatic atrial defibrillator which includes a mechanism for sensing the occurrence of atrial fibrillation in a patient's heart and in response thereto delivers an atrial defibrillation pulse. The device also has the ability to determine whether the patient is likely to be asleep. Defibrillation pulses which are at energy levels which would normally be painful to the patient are delivered only in response to occurrences of atrial fibrillation while the patient is determined to likely be asleep. Defibrillation pulses at lower, non-painful levels may be delivered while the patient is not determined to be asleep.

Abstract: The device senses Natural Heart Acceleration (NHA), isolating at least one segment (t) thereof corresponding to an isovolumetric phase, such as isovolumetric contraction (P1, P2) and/or isovolumetric relaxation (P3, P4). Preferentially, the action of isolation of the aforesaid segment is made starting from the electrocardiogram (ECG) signal. Among other things, the device may be used to carry out pacing functions (pacemaker, defibrillator, pacer cardioverter defibrillator) and/or to pick up, possibly by telemetry, data on the myocardial function and/or also to control a system of drug administration.

Abstract: An electrotherapy method and apparatus for delivering a multiphasic waveform from an energy source to a patient. The preferred embodiment of the method comprises the steps of charging the energy source to an initial level; discharging the energy source across the electrodes to deliver electrical energy to the patient in a multiphasic waveform; monitoring a patient-dependent electrical parameter during the discharging step; shaping the waveform of the delivered electrical energy based on a value of the monitored electrical parameter, wherein the relative duration of the phases of the multiphasic waveform is dependent on the value of the monitored electrical parameter.

Abstract: A cardiac blood flow sensor includes a light source and a photodetector within a housing. The light source projects a beam through a fiber optic line having a first end optically connected to the housing and a distal tip positioned within the patient's heart. Light intermittently reflected off the moving blood cells is transmitted back through the optic line to the detector, which generates a varying signal proportional to the reflected light, and thus proportional to the blood flow rate within the heart. The flow sensor may be contained in a common housing with a defibrillator that is implanted in a patient. The sensor may remain inactive until a potentially unhealthy heart beat rate is detected, upon which the light source is activated. The defibrillator may be activated only if the flow sensor has detected a blood flow rate below a predetermined level.