Abstract: A connector for clamping lead bodies into connector bores in implantable medical devices has several alternative embodiments. In each there is a handle that has a fixed relationship with an axle member that connects through the connector block perpendicular to the long axes of the connector bores for the leads. A large, manually operable flag or handle member clicks into position to lock the lead in by positioning a saddle portion against the lead body in the bore. The handle may be split into legs or the axle may be split into legs and the space between the legs filled with medical adhesive if desired. Likewise a soft material elastomer may surround the saddle portion to prevent rough contact with the lead body.

Abstract: An automatic, body-implantable medical device having at least two modes of operation is disclosed. The device is provided with circuitry for automatically detecting when the device has been implanted in a patient, so that the device can automatically switch from a first mode to a second mode of operation upon implantation. In one embodiment, the first mode is a power conserving mode in which one or more non-essential sub-systems of the device are disabled. Prior to detection of implant, at least two conditions of the device known to reflect whether the device has been implanted are monitored. After implant has been detected, situations in which power to the device is disrupted and then restored will cause the device to enter a predefined "power-on-reset" mode of operation. Prior to detection of implant, however, such conditions do not result in the device entering the power-on-reset mode, or this mode is reset.

Abstract: An automatic, body-implantable medical device having at least two modes of operation is disclosed. The device is provided with circuitry for automatically detecting when the device has been implanted in a patient, so that the device can automatically switch from a first mode to a second mode of operation upon implantation. In one embodiment, the first mode is a power conserving mode in which one or more non-essential sub-systems of the device are disabled. Prior to detection of implant, at least two conditions of the device known to reflect whether the device has been implanted are monitored. After implant has been detected, situations in which power to the device is disrupted and then restored will cause the device to enter a predefined "power-on-reset" mode of operation. Prior to detection of implant, however, such conditions do not result in the device entering the power-on-reset mode, or this mode is reset.

Abstract: An antenna apparatus for an implantable medical device is adapted and disposed to have an increased telemetry range by providing a plurality of antennas connected in parallel with each other, and physically separated from each other. The antennas may be mounted within the IMD can or they may be located externally, outside the IMD can, but associated and mounted to the IMD can package. The antennas may have coils wound around an air-core or a non-air core such as ferrite. There can be any number of them but it is preferrably a number between 1 and 10.

Abstract: A minimally invasive implant, means for insertion, and description of how to most efficiently use it are described n several embodiments. This implant preferably has a segmented looping memory for storing triggered physiologic events. Preferred events for setting autotriggers to record physiologic signals occurring during events include arrhythmias and syncopal events. Preferably the device can function without a microprocessor. An outside device or other patient activated manual trigger is included. Auto triggers and manually set triggers may be of different sizes. The preferred physiologic events are ECG signals. Electrode spacing can be critical. Additional sensors may be provided to the device. Preferred communications with the device is through telemetry such as is used for pacemakers and other implanted devices.

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: A system and methodology permit facilitated review of atrial pacing threshold testing. Primarily the system allows the ventricular rate to fall substantially below the atrial rate, preferrably to 1/2 the atrial pacing rate. A number of ways to accomplish this are described including forcing mode switches between ADI and DDI between beats, except where ventricular events follow atrial paces. Application of the technique and system to clinical, implant and follow up situations is described.

Abstract: The present invention provides apparatus, systems, and methods for accurately calibrating a pressure sensor which is incorporated into a lead, e.g., a pacemaker lead, prior to implant into a patient. A calibration vessel is provided which has a housing which forms a reservoir for containing the portion of the lead having the pressure sensor. The vessel also has a connector for receiving a reference pressure into the reservoir, and a sealable opening for receiving the distal end of the lead that carries the pressure sensor. The calibration vessel can be used in a system comprising an electronic display module and an external pressure reference, for establishing an accurate sensor baseline for zero pressure; and can also be used in a system comprising an electronic display module, a reference pressure input source, and a manometer for establishing an accurate scale factor for the lead pressure sensor.

Abstract: Method and apparatus for detection of non-physiologic senses checks the output of the sense amplifier of an implanted medical device where the inputs of the sense amplifier are adapted to connect to a living body for sensing electrical signals representative of physiologic events, and especially heart beats, and if that sense output senses a physiologic event within a predetermined time after a non-physiologic event is sensed by another circuit also connected to receive electrical signals from said living body, then there is reported out a signal indicating that the event sensed by the sense amplifier is of a non-physiologic nature. Various uses are accomplished with the information in these output signals.

Abstract: A method and apparatus for automatic determination of a pacemaker patient's pacing stimulation threshold. Circuitry is provided in a pacemaker for obtaining a signal reflecting cardiac impedance, which is known to reliably reflect certain aspects of cardiac function. Circuitry is also provided for monitoring the cardiac impedance waveform during a predetermined capture detect window following delivery of stimulating pulses. One or more values are derived which characterize the morphology of the impedance waveform during the capture detect window associated with each stimulation pulse delivered. These values are compared to predetermined control values in order to assess whether a stimulation pulse has achieved cardiac capture. The assessment of whether cardiac capture has been achieved is also based partly upon the conventional sensing of atrial and/or ventricular cardiac signals occurring during the capture detect window.

Abstract: In an implanted medical device, a method and apparatus for detecting pressure waves caused by movement of a body organ, muscle group, limb or the like and transmitted through a catheter or lead body to the implanted medical device employing a pressure wave transducer mounted in relation to the proximal end of the catheter or lead to detect the transmitted pressure waves. The system may also include a reference transducer having the same pressure wave response characteristics as the pressure wave transducer but isolated from the proximal connector end for providing a reference signal including common mode pressure wave noise that both transducers are simultaneously subjected to. The pressure wave signal and the reference signal are preferably amplified, bandpass filtered to the body pressure wave of interest and stored, telemetered out or used to trigger a device operation.

Abstract: A circuit for determining lead impedance during the time a pacing or other stimulating electrical pulse is being delivered measures current and voltage simultaneously to check for open circuits or short circuits based on different thresholds. The detection of a bad lead can force a double pulse to be delivered in real time in a unipolar configuration. Switching from unipolar to bipolar configuration based on detecting a bad bipolar circuit can be supported.

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: Pacemaker designed for support of both orthotopic and heterotopic transplants has three lead bore connector block assembly and dedicated or dedictable amplifiers for pacing and sensing configurations unique to transplant situations. The provision of definable amplifier assignments allows for enhanced sensing, capture detection and therapy.

Abstract: An AV search method and apparatus is taught with some variation described. It allows a pacemaker to find the appropriate AV interval so as to avoid pacing in the ventricle when it is not necessary, even if there is intermittent AV conduction in the patient. Also, an adaptive PVARP method and apparatus is disclosed that allows the PVARP and AV interval to be adjusted together automatically.

Abstract: Capture detection and stimulation threshold-measurement methods and apparatus for deriving atrial and ventricular pace pulse (A-pace and V-pace) stimulation energy strength-duration data. In a first atrial and ventricular threshold test regimen for use with patients having intact A-V conduction or first degree AV block, A-pace pulses are delivered at a test escape interval and A-V delay. Atrial loss of capture (ALOC) in response to an A-pace test stimulus is declared by the absence of a detected ventricular depolarization (V-event) in the latter portion of the paced A-V delay interval following the delivery of the A-pace test stimulus. In the ventricular threshold test regimen, a V-pace test stimulus is delivered after a shortened A-V delay. Ventricular loss of capture (VLOC) is declared by the detection of a V-event in the ventricular refractory period of the V-pace test stimulus.

Abstract: A method and apparatus for automatic determination of a pacemaker patient's pacing stimulation threshold. Circuitry is provided in a pacemaker for obtaining a signal reflecting cardiac impedance, which is known to reliably reflect certain aspects of cardiac function. Circuitry is also provided for monitoring the cardiac impedance waveform during a predetermined capture detect window following delivery of stimulating pulses. One or more values are derived which characterize the morphology of the impedance waveform during the capture detect window associated with each stimulation pulse delivered. These values are compared to predetermined control values in order to assess whether a stimulation pulse has achieved cardiac capture. The assessment of whether cardiac capture has been achieved is also based partly upon the conventional sensing of atrial and/or ventricular cardiac signals occurring during the capture detect window.

Abstract: There is provided an improved pacing system and method which monitors when the ventricle has become appropriately filled with blood and controls the delivery of each ventricular pace pulse to substantially coincide with desired ventricular filling, e.g., when the chamber has substantially filled. By this technique, the desired time for delivering the ventricular pace pulse is determined on a beat-by-beat basis, providing an improved physiologically optimum mode of pacing. The physiologically ventricular pacing technique of this invention is applicable either to a single chamber pacemaker, or to a dual chamber pacemaker, and in either case enables the important improvement of delivering the pace pulse at the most physiologically appropriate time.

Abstract: Some false tachy detection prevention algorithms miss blocked 2:1 sensing and therefore miss some true tachy situations. Here an algorithm that uses sensed far field R waves to determine whether to search for blocked 2:1 sensing is implemented and a search algorithm is also described.

Abstract: An anodal stimulation method and apparatus for the prevention or treatment of tachyarrhythmias using anodal stimulation (AS) energy for effecting hyperpolarization of myocardial cells of a heart chamber to enhance the relaxation thereof in the diastolic phase and to enhance cardiac function, reverse or inhibit cell activation, and thereby treat or prevent tachyarrhythmias. In a preemptive mode with a recognizable ventricular rhythm, the AS pulse is optimally timed to be delivered in an AS delivery interval following an AS delay interval timed from a preceding ventricular depolarization to effect maximal cardiac relaxation and suppress aberrant electrical activity. In a reactive mode responsive to a detected tachyarrhythmia requiring delivery of an anti-tachyarrhythmia therapy, e.g. a cardioversion shock therapy, the AS pulse is delivered during charging of high voltage output capacitors providing the cardioversion shock energy.