Abstract: Methods and apparatus are disclosed herein that advantageously combine beneficial aspects of overdrive pacing and multi-site atrial pacing in order to provide an improved treatment for atrial fibrillation. The methods and apparatus include sensing of atrial activity at multiple sites within the atria at an overdrive pacing rate to detect intrinsic atrial depolarization, and delivery of pacing pulses to multiple sites within the atria to prevent or terminate arrhythmias such as atrial fibrillation.

Abstract: An apparatus and a method for identifying fusion beats as part of an automatic capture routine in a cardiac stimulation device are disclosed. By requiring each post-pulse electrical response to be closely correlated with an expected morphology for either a capture condition or a loss-of-capture condition before classification of the post-pulse electrical response as either capture or loss-of-capture respectively, the present invention is able to identify fusion beats. In various embodiments, this fusion identification is performed using both template matching and assessment of particular detection features. Moreover, in one embodiment, a moving average and a standard deviation are maintained for each detection feature, thereby creating an automatically adjusting evoked response detection threshold.

Abstract: An exemplary method includes determining, in vivo, position, displacement and/or spatial time derivatives of myocardial tissue. Such determinations are optionally made with respect to systolic and/or diastolic cycles. Further, position, displacement and/or spatial time derivatives may be used in cardiac diagnosis or therapy. Other exemplary methods, devices and/or systems are also disclosed.

Abstract: Methods and devices are provided for reducing motion artifacts when monitoring volume changes in blood vessels. Light having a first wavelength and light having a second wavelength are transmitted through a human appendage, toward the epidermis of a patient, or through tissue within the body of a patient. A portion of the light having the first wavelength and a portion of the light having the second wavelength is received. A first signal is produced based on the received portion of light having the first wavelength. A second signal is produced based on the received portion of light having the second wavelength. One of the first and second signals is subtracted from the other to produce a plethysmography signal that is representative of volume changes in blood vessels of patient tissue.

Abstract: A body implantable lead comprises a lead body including a conductive polymer electrode disposed along a distal end portion of the lead body for performing one or more of the functions consisting of pacing, sensing, cardioversion and defibrillation. An electrical conductor, preferably in the form of a multistrand cable conductor, couples the conductive polymer electrode with a proximal end of the lead body. The conductive polymer electrode encapsulates the conductor and is in electrical contact therewith along the length, and preferably along substantially the entire length, of the conductive polymer electrode. The lead body may comprise a multilumen polymer housing, the conductor being contained within one of the lumens of the housing. The conductive polymer electrode may be disposed within a window formed in the lead body.

Abstract: A surface electrocardiogram (EKG) is emulated using signals detected by the internal leads of an implanted device. The emulation is performed using a matrix-based technique that separately emulates each of the individual signals of a multiple-lead EKG, rather than merely emulating a single combined EKG. In one example, each of the twelve signals of a standard 12-lead EKG are individually emulated, allowing for separate processing and display. The emulation technique takes into account factors affecting the relative locations of the internal leads, such as respiration and posture, to thereby provide a more accurate emulation. A calibration technique is provided for calibrating the EKG emulation for use with a particular patient and a verification technique is provided for automatically verifying the reliability of the emulation. Any significant loss in emulation reliability is likely caused by lead dislodgment and so automatic detection of possible lead dislodgment is also achieved.

Abstract: An implantable medical lead comprises an insulating lead body housing having an outer surface. A thin, flexible membrane surrounds the insulating housing, the membrane having an inner surface confronting the outer surface of the housing. A lubricious interface between the inner surface of the membrane and the outer surface of the housing facilitates movement of the insulating housing relative to the membrane in response to frictional engagement of the membrane with adjacent structure. Also disclosed is a method of fabricating such a lead.

Abstract: Techniques are described for overdrive pacing the heart using a pacemaker. Other techniques are described for adaptively adjusting overdrive pacing parameters so as to achieve a determined target degree of pacing of, for example, 95% paced beats. By adaptively adjusting overdrive parameters to maintain a target degree of pacing, the average overdrive pacing rate is minimized while still maintaining a high number of paced beats, thereby reducing the risk of a tachyarrhythmia occurring within the patient. Still other techniques are described for increasing an overdrive pacing rate by an amount related to a current overdrive pacing rate.

Abstract: An implantable single-pass cardiac stimulation lead provides for placement of electrodes into electrical contact with two chambers of a patient's heart. The lead includes an inner lead body having at least one electrode at its distal end and an outer lead body having at least one electrode at its distal end. The outer lead body has an internal lumen that slidingly receives the inner lead body. The inner lead body is extendable from the outer lead body at a point proximal to the distal end of the outer lead body. The sliding of the inner lead body relative to the outer lead body enables the inner lead body distal electrode to have a varying distance from the outer lead body distal electrode and enables the inner lead body to extend into the coronary sinus region of the heart to place the inner lead body electrode into electrical contact with the left ventricle.

Abstract: An implantable cardiac stimulation device delivers successive defibrillation waveforms using alternating counter electrodes selected from a case electrode and an electrode located on a coronary sinus lead. The case electrode and coronary sinus electrode may be selected individually in an alternating fashion such that the defibrillation pathway alternates between two single pathways during a defibrillation regimen. The case electrode and the coronary sinus electrode may also be used simultaneously in parallel to create a dual pathway. Defibrillation waveforms may then be delivered in a cyclical fashion between the individual counter electrodes and the combined counter electrodes such that alternation between single pathways and a dual pathway is achieved.

Abstract: A connector assembly releasably affixes a lead on an implantable medical device. The lead includes a lead body. The connector assembly comprises a support, a side clamp defining with the support confronting surfaces configured to receive a proximal end portion of the lead body. A fastener is adapted to be received by the support for urging the side clamp toward the support and for clamping the proximal end portion of the lead body between the confronting surfaces. The fastener may extend through the side clamp and may be threadedly received by the support. Further, the support may carry a retainer for inhibiting the removal of the fastener from the support. The side clamp and the support may define additional confronting surfaces configured to receive a proximal end portion of an additional lead body, the fastener being adapted to urge the side clamp toward the support to clamp the proximal end portion of the additional confronting surfaces.

Abstract: Cardiac electrical events are detected by comparing signal vectors with pre-determined classification zones representative of different cardiac events. The signal vector is generated by sensing the voltages between various combinations of electrodes, such as A-tip to V-tip, A-tip to A-ring, and A-ring to V-ring. The signal vector is compared with a set of classification zones corresponding to different events, such as P-waves, R-waves, T-waves, A-pulses, and V-pulses, to determine whether the vector lies within any of the classification zones. In this manner, cardiac events are detected using only the voltages received from the electrodes and no refractory periods or blanking periods are required to distinguish one event from another. The classification zones vary from patient to patient and a technique is provided herein for generating a set of vector classification zones for a particular patient.

Abstract: An electrolytic capacitor with a polymeric housing in the form of a pocket defining a chamber, with an opening along a selected edge. The opening has opposed sides that are sealed together to provide a seam. A number of conductive layers are positioned within the chamber, and a feed-through conductor element has a first end electrically connected to the layers. An intermediate portion of the feed through passes through the seam, and an external portion extends from the housing. The housing may be vacuum formed high density polyethylene, with the feed-through contained in an elastomeric sleeve having a flattened cross section to be readily received in the seam, and to accommodate thermal expansion differences between the housing and the feedthrough. The device may be manufactured by inserting a stack of layers in the pocket, and thermally welding across the opening of the pocket on a single weld line.

Abstract: A surface electrocardiogram (EKG) is emulated using signals detected by the internal leads of an implanted device. The emulation is performed using a matrix-based technique that separately emulates each of the individual signals of a multiple-lead EKG, rather than merely emulating a single combined EKG. In one example, each of the twelve signals of a standard 12-lead EKG are individually emulated, allowing for separate processing and display. The emulation technique takes into account factors affecting the relative locations of the internal leads, such as respiration and posture, to thereby provide a more accurate emulation. A calibration technique is provided for calibrating the EKG emulation for use with a particular patient and a verification technique is provided for automatically verifying the reliability of the emulation. Any significant loss in emulation reliability is likely caused by lead dislodgment and so automatic detection of possible lead dislodgment is also achieved.

Abstract: An implantable stimulation device delivers a stimulation pulse in the ventricular chamber of a patient's heart and automatically adjusts a post-ventricular atrial blanking period. The stimulation device generates a ventricular stimulation pulse to trigger an evoked response, in order to produce a ventricular far-field signal that follows a successfully captured ventricular stimulation pulse. The stimulation device further includes an atrial sense circuit that senses the ventricular far-field signal, and a control system that adaptively segments the post-ventricular atrial blanking period in a post-ventricular atrial blanking period (PVAB) which is fixed in duration, and a variable far-field interval (FFI) window.

Abstract: A telemetry architecture is described that enables multiple programmers to concurrently interact with associated implantable medical devices within a viable telemetry range. The programmers communicate with implantable medical devices over one or more communication channels. Inter-programmer communication is accomplished over a particular communication channel that may be selected from one of the programmer-to-device channels or via an independent back channel. The programmers use the inter-programmer communication to coordinate communication between associated programmers and implantable medical devices within the viable telemetry range.

Abstract: Optimization of evoked response detection in an automatic capture detection system employed by an implantable cardiac stimulation device is presented. Patient state information is used to determine the appropriate settings of variables that are associated with the evoked response signal detection algorithm. The variables used by the evoked response signal detection algorithm are first established for the patient in a variety of positions. During operation of the implantable cardiac stimulation device, the patient state is monitored and the variables used by the evoked response signal detection algorithm are adjusted accordingly.

Abstract: Exemplary methods and devices for determining whether atrial fusion, atrial pseudofusion and/or atrial native activity have occurred. Various methods and/or devices are suitable for use with atrial autocapture. Other methods, devices and/or systems are also disclosed.

Abstract: An assist device for an implantable cardiac stimulation lead system includes a handle for a steerable guidewire system. An inner conductive guidewire with a distal tip electrode is pre-shaped into a free state curved configuration. An outer sheath is coaxial with the guidewire and relatively slidable between a first position restraining the guidewire to a straight condition and a second position withdrawn from a freed length of the guidewire allowing it to assume its free state curved condition. A collar on the outer sheath is movable along the handle for moving the sheath between the first and second positions. An electrical terminal is in electrical continuity with the tip electrode such that a pacing system analyzer connected between the electrical terminal and a reference electrode in the body is operable for seeking a location at which optimal pacing parameters can be determined prior to final implantation of the lead system.

Abstract: An implantable lead for electrical stimulation of the body includes an elongated multi-lumen proximal tube composed of a first material having a first lumen for freely receiving a guidewire therethrough, a cable conductor extending between proximal and distal ends and received in a second lumen of the proximal tube, an elongated distal tube composed of a second material extending between proximal and distal ends having at least one lumen therein, a distal tip electrode attached to the distal end of the distal tube, a coil conductor received in the lumen of the distal tube extending between the proximal end thereof and the distal end thereof and being joined at the distal end to the distal tip electrode, and a joint assembly for electrically and mechanically connecting the distal end of the cable conductor to the proximal end of the coil conductor.