Abstract: A method an apparatus for treating fibrillation, particularly atrial fibrillation. In response to detection of fibrillation, a high frequency, low energy pulse burst is delivered via pacing electrodes, accompanied by a high energy pulse delivered via defibrillation electrodes. The low energy pulse burst is preferably delivered to an area of the heart which exhibits relatively lower current density during delivery of the high energy pulse.

Abstract: A system and method of operation thereof for storing patient related data within an implanted medical device and retrieving and regenerating the patient related data using a generative grammar and graphic user-interface software in a programmer having uplink and downlink telemetry capabilities. A generative grammar resident in the programmer is selected, and it prompts a physician or other user to enter patient specific variables by selecting menu choices or making data entries in data entry fields which generated by grammar rules while constructing a textual narrative report about the patient in a human language. Simultaneously, in the programmer, a digital patient related data bit string is assembled that identifies the generative grammar and encodes the choices and values as they are entered by the physician. Also simultaneously, internal computer records of the patient related data are stored in computer memory.

Abstract: A method and apparatus for treating atrial tachyarrhythmias, particularly atrial fibrillation. High energy pulses are delivered between electrodes located in the right atrium/SVC, the left pectoral region and the coronary sinus/great vein, with the left pectoral and coronary sinus/great vein electrodes connected in common. Optionally a ventricular electrode may also be employed in conjunction with one or more of the other listed electrodes to accomplish ventricular cardioversion or defibrillation.

Abstract: A threshold detection and capture verification system for a cardiac pacemaker/cardioverter/defibrillator (PCD) of the type comprising an implantable pulse generator (IPG) and a lead system including one or more pacing leads each having a proximal end coupled to the IPG and a distal end with at least one pace/sense electrode in contact with a patient's heart and one or more defibrillation leads having a proximal end coupled to the IPG and a distal end having one or more defibrillation electrodes in contact with a patient's heart or otherwise implanted within the patient's body. In a threshold detection operation, a sense amplifier is coupled to a selected threshold sensing electrode pair comprising at least one and preferably two defibrillation electrodes, and pacing pulses are applied to a pair of pace/sense electrodes. The evoked responses to pacing pulses having energy levels exceeding the stimulation threshold of the heart are detected through the sense amplifier and capture verified.

Abstract: An adaptive, performance-optimizing communication system for communicating with an implanted medical device in which signals are transmitted and received in accordance with predetermined, interrelated operational parameters, such as transmission rate, transmitter power, and the like. Various aspects of system performance, including bit error rate in received signals, the strength of received signals, the signal-to-noise ratio of received signals, the presence of local RF noise and non-telemetry related RF signals, and the like, are dynamically monitored by the communication system, to determine whether predetermined system performance goals are being met. If it is determined that one or more system performance goals are not being met, one or more operational parameters may be automatically adjusted so that desired performance can be achieved.

Abstract: A method and apparatus for preventing fibrillation, particularly atrial fibrillation or flutter. In response to detection of an atrial premature beat at any given site in the atrial chamber, a low energy pulse burst is delivered to multiple sites of at least one chamber of the atrium for a time period sufficient to depolarize the entire atrium. Preferably, multiple pairs of sense electrodes are distributed about an atrial chamber or both atria to define discrete sensing sites and to widely distribute the simultaneously applied pacing energy pulse burst. Bradycardia pacing between the multiple electrode pairs is also preferably provided.

Abstract: A medical electrical lead having an elongated lead body provided with an internal longitudinally extending lumen carrying an elongated stranded or cabled conductor and an electrode coil, located on said lead body. The coil is coupled to the conductor by a conductive sleeve having a tubular portion which has an internal lumen through which the conductor passes and a groove or bore which engages only a portion of a turn or turns of the electrode coil, such that the coil is oriented generally perpendicular to the internal lumen of said sleeve and to the conductor.

Abstract: A pacemaker system adapted to deliver pacing pulses in the presence of fibrillation. The pacing pulses are delivered via large surface area electrodes of the type normally used to accomplish defibrillation or cardioversion using high voltage pulses. An extended pulse train is delivered in order to gradually entrain greater portions of heart tissue, until a sufficient percentage of tissue is entrained to interrupt fibrillation. The invention is believed most applicable to treatment of atrial fibrillation.

Abstract: Disclosed are method and apparatus for creating a cantilever accelerometer beam by mechanically forming an accelerometer from a piezoelectric substrate. The inherent structure of the accelerometer provides a means for employing surface mount technology (SMT), or a protective package may be utilized to couple the accelerometer to the hybrid circuit within an implantable pacemaker. The sensor's structure is defined by three members. The first and second members are used to couple the sensor to the hybrid circuit and the third member defines the cantilever accelerometer beam, which generates an electrical output signal indicative of a patient's activity.

Abstract: Adjustable, flexible suture rings, tricuspid and tricuspid annuloplasty rings having internal drawstrings that emerge from the rings on the annular faces so that the drawstring knots are out of the bloodstream, the drawstrings being contained in clearly marked channels, the mitral ring having a curved semi-flexible stiffener member in the anterior segment to maintain intertrigonal distance during implantation are disclosed.

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, multi-programmable 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: A method and apparatus for inducing fibrillation in a patient, for example to verify the efficacy of a defibrillator system. In the disclosed embodiment, an implantable cardioverter-defibrillator has an output stage coupled via a plurality of leads to the patient's heart. When it is desired to induce fibrillation in the patient, the device's control circuitry initiates an output capacitor charging cycle and subsequent delivery of a multi-phase fibrillation inducing stimulus to the heart. The multiple phases of the stimulus reflect an incremental discharging of the output capacitor. In one embodiment, the stimulus has three phases, with the first two separated by a time interval equal to or slightly less than the patient's "vulnerability window," which is defined as the time period following a paced cardiac event during which repolarization of the cardiac muscle is occurring, rendering the heart susceptible to induced fibrillation.

Abstract: Disclosed is a quick change battery drawer for rapidly substituting a fresh battery for an exhausted battery in the battery drawer of an external, battery powered therapeutic electrical stimulator while the stimulator continues to emit electrical stimulation to treat a patient. A push button is normally biased outward and a release member latches the battery drawer in the latched position through the interaction of first catches on the battery drawer and second catches on the release member. The terminals of a battery loaded in the battery drawer bear against and compress spring terminals that thereby spring load the battery drawer with a bias force and assist in keeping the battery drawer latched. When the release button is depressed, the first and second catches are disengaged, and the bias force acts to eject the battery and battery drawer forcefully into an ejected position where the battery drawer is prevented from completely ejecting from the side opening.

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: One embodiment of the present invention is a mode switching method and apparatus for an external, dual chamber cardiac pacemaker having multiple single chamber and dual chamber primary pacing modes and user adjustable atrial and ventricular sensitivities. The dual chamber demand pacing mode, e.ga. the DDD or DDI mode, is in effect as long as the atrial and ventricular pace pulse amplitudes are set by the user within an operative range. The pacing mode is switched to a single chamber demand mode when one of the atrial and ventricular pace pulse energies is set to an inoperative setting which preferably is a no output setting. If the atrial pace pulse amplitude is set to no output, then the mode is switched to a single chamber demand mode with ventricular sensing and pacing, preferably the VVI mode. If the ventricular pace pulse amplitude is set to no output, then the mode is switched to a single chamber mode with atrial sensing and pacing, preferably the AAI mode.

Abstract: A method and apparatus for treating fibrillation, particularly atrial fibrillation. In response to detection of fibrillation, a series of low energy pulse bursts is delivered, separated by defined inter-burst intervals, and including bursts unsynchronized to heart depolarizations. Detection of termination of fibrillation during inter-burst intervals results in cancellation of further pulse bursts to prevent reinduction of fibrillation.

Abstract: A cardioversion/defibrillation lead and method of implantation thereof for location in a human heart of the type comprising an elongated lead body having proximal and distal end sections and having a looped intermediate section. The proximal and distal end sections of the lead have generally straight configurations, and the intermediate section is constructed such that when the distal section is located at the apex of the right ventricle of the heart, the loop of the intermediate section is located in the outflow tract of the heart. One or more elongated defibrillation electrode(s) extends along the intermediate section of the lead body.

Abstract: A method of and apparatus for determining the physical posture of a patient's body, having a superior-inferior body axis, an anterior-posterior body axis and a lateral-medial body axis, in relation to earth's gravitational field. A medical device having first, second and, optionally, third DC accelerometers having sensitive axes mounted orthogonally within an implantable housing is adapted to be implanted with the sensitive axes generally aligned with the patient's body axes. Each DC accelerometer generates DC accelerometer signals having characteristic magnitudes and polarities on alignment of the sensitive axis with, against or normal to earth's gravitational field and DC accelerometer signals of varying magnitudes and polarities when not so aligned. Body position may be determined through comparison of the magnitudes and polarities of the DC accelerometer signals with the characteristic magnitudes and polarities.

Abstract: A power supply arrangement for a battery-powered device includes a high energy density capacitor which is selectively coupled to the device's battery. In one embodiment, the device includes a first circuit which requires a continuous operational power supply voltage to be applied to its power supply input, and further includes a second circuit periodically operates in a peak phase in which it places a high demand upon the device's battery. During normal operation of the device, the first circuit's power supply input and the high energy density capacitor are coupled to the battery so that operational power for the first circuit is provided directly from the battery, and the high energy density capacitor is charged by said battery.

Abstract: A medical electrical lead having a multiple conductors located within an elongated lead body which is provided with multiple conductor lumens each containing a conductor and with at least one compression lumen which does not contain a conductor. The conductor lumens are spaced from one another by a first, minimum spacing and the compression lumen or lumens are located intermediate the conductor lumens and are spaced from the conductor lumens by a second, minimal spacing of less then said first minimum spacing. The centers of the compression lumens are located along lines which pass through the both the center of a conductor lumen and the center of the lead body. The arrangement of the conductor and compression lumens enhances the lead's ability to survive crushing forces such as applied by the first rib and clavicle.