Abstract: A patient monitoring and/or therapy delivery system and method employing an implantable medical device for sensing absolute physiologic signal values within the body of a patient, e.g., absolute blood pressure, temperature, etc., and an external monitoring device for monitoring and conveying ambient signal values to the implantable medical device, wherein the absolute physiologic signal values and the ambient signal values are combined to derive relative physiologic signal values for storage and/or control of a therapy provided by the implantable medical device. In the context of an implantable physiologic monitor, the relative and optionally, the absolute and/or ambient physiologic signal values are stored in memory for telemetry out to an external programmer in an uplink RF telemetry transmission initiated by medical personnel operating the external programmer. In the context of an implantable therapy delivery device, the relative physiologic signal values are also employed in therapy delivery algorithms.

Abstract: An arrangement for introducing and implanting the electrode(s) of an endocardial implantable cardiac lead at a cardiac implantation site within a heart chamber or vessel. An elongated guide body formed of flexible material and extending between a guide body proximal end and a guide body distal end is advanced transvenously to position the guide body distal end in relation to the cardiac implantation site. A guide body tracking mechanism is coupled with the lead distal end for receiving and slidingly engaging the guide body to allow the cardiac lead to be advanced along the guide body until the electrode is positioned at the cardiac implantation site. Pusher mechanism formed of an elongated pusher body of flexible material extends between a pusher body proximal end and a pusher body distal end and has a cardiac lead engaging mechanism for engaging the cardiac lead at or adjacent the distal lead end.

Abstract: An implantable electrical lead having a lead body fabricated of a first, inner tube and a second, outer tube, the first, inner tube, mounted slideably within the outer tube, the outer tube overlapping the inner tube along at least a portion of its length; and having a conductor extendible along a portion of its length, mounted within and extending along the first and second tubes with the extendible portion of the conductor extending within a region in which the outer tube overlaps the inner tube and having an electrode mounted to a distal portion of the lead body, coupled to the conductor. The inner and outer tubes are preferably approximately the same length, and the extendible portion of the conductor preferably extends along a majority of its length. The extendible conductor may be a coiled conductor provided with an insulative coating.

Abstract: A pacemaker provided with a mode switching feature adapted to stabilize ventricular heart rate during atrial fibrillation. In a preferred embodiment of the invention, the device nominally operates in an atrial synchronized pacing mode such as DDD, DDDR, VDD or VDDR. In response to detection of atrial rhythm characteristics consistent with atrial fibrillation, the device switches into a non-atrial synchronized, ventricular rate stabilization pacing mode with the base ventricular pacing rate modulated on a beat by beat basis based upon preceding intrinsic or paced ventricular heartbeat intervals to adjust the pacing interval towards a desired preset rate stabilization target pacing interval which is typically less than the programmed base pacing interval of the 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 implantable device which stores information indicative of events occurring within a patient's body and related to operation of the device for transmission to an external device in response to a request from the external device. The implanted device is provided with a mechanism for retaining information as to the state of the information stored in the device at the time of a preceding request or interrogation from the external device and for storing cumulative information indicative of the operation of the device or events occurring within the patient's body over a time frame spanning multiple interrogations or requests from the external device. The two types of stored information together may be employed by the implanted device or the external device to derive information indicative only of events occurring since a preceding interrogation of the implanted device by the external device.

Abstract: An ablation catheter particularly adapted for use in ablation of cardiac tissue. The catheter is provided with an elongated electrode, intended to make contact with tissue to be ablated, in the heart, along its length. The electrode is mounted to a segment of the catheter which is porous, and the catheter is provided with an internal lumen for delivery of a conductive fluid such as Ringer's solution, to the porous portion of the catheter body, so that the conductive solution may be delivered along the entire length of the electrode.

Abstract: An implantable medical electrical lead having a lead body including a stranded or cabled conductor extending therein and an electrical connector mounted to a proximal end of the lead body and coupled to the stranded or cabled conductor and having a fabric tube molded into a proximal portion of the lead body adjacent the electrical connector. The fabric may be a polyester mesh formed or rolled into a tube and is preferably molded into the proximal portion of said lead body adjacent its exterior surface. The proximal portion of the lead body may be fabricated of silicone rubber or polyurethane.

Abstract: A lead and a lead system for dispersion of a cardioversion/defibrillation electrode formed of one or more small diameter defibrillation electrodes in a heart chamber and for attaching a pace/sense electrode in contact with the heart. The small diameter defibrillation electrode or electrodes extend distally from the distal end of the lead body. If multiple electrodes are employed, they are preferably biased to spread apart when unrestrained and have a cross-section size small enough to be inserted into interstices of trabeculae in the ventricular chamber. The distal ends of the defibrillation electrodes may be free of attachment to the lead body or may be attached by a weak bond to the distal portion of the lead.

Abstract: An implantable antiarrhythmia device which detects and classifies arrhythmias of the human heart, and delivers appropriate therapy. The device employs a method of arrhythmia classification based on a set of prioritized rules, each of the rules defining a plurality of criteria based upon characteristics of sensed depolarizations of heart tissue, each rule being met when the criteria associated with the rule are met. Some rules, when met, trigger delivery of antiarrhythmia therapy. Other rules, when met, inhibit delivery of antiarrhythmia therapy. The rules may be met simultaneously, and if so, the highest priority rule governs the behavior of the device.

Abstract: An implantable medical lead for use with an implantable cardioverter defibrillator, a method of manufacture and a system employing the lead and cardioverter/defibrillator in combination. The lead is provided with an elongated insulative lead body carrying a cardioversion/defibrillation electrode, which includes a first portion displaying essentially equal attenuation of positive and negative voltage pulses and a second portion displaying differential attenuation of positive and negative voltage pulses. The cardioveter/defibrillator provides a biphasic pulse in which a higher amplitude phase of the pulse is differentially attenuated by the electrode. The electrode is fabricated in whole or in part of a valve metal such as tantalum, anodized and annealed to provide a thick, durable oxide coating.

Abstract: An implantable pacemaker employing an arrhythmia prevention pacing modality particularly optimized for inclusion in dual chamber pacemakers and anti-arrhythmia devices which include dual chamber pacemakers. When the pacing mode is in effect, the device alters timing of scheduled atrial and/or ventricular pacing pulses in response to depolarizations sensed during the refractory periods and to ventricular depolarizations sensed outside of the pacemaker's A-V escape intervals. The arrhythmia prevention pacing mode is activated and deactivated in conjunction with the operation of arrhythmia detection features which may also be employed by the device to trigger delivery of anti-arrhythmia therapies.

Abstract: A lead insulator which provides resistance to tearing and/or abrasion for implantable flexible electrical lead insulators having a body of silicone elastomer material. A relatively thin layer of a second silicone is applied as an overcoat to a more substantial primary or first insulator body. The second silicone is more resistant to tearing and/or abrasion than the elastomer comprising the body of the insulator. Because tearing and/or abrasion are surface phenomena, only a relatively thin layer of the second material is particularly required and the mechanical properties of the primary material will determine the overall mechanical properties of the lead insulatior per se.

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: An implantable medical device system including an implantable electronic device having multiple electrical connectors and an associated electrical lead also having a corresponding set of electrical connectors which engage with the connectors on the device. The lead has a connector assembly mounted to its proximal end, including the lead's electrical connectors and a mechanical connector. The device has a connector block with a bore extending therethrough sized to receive the connector assembly of the lead. A pulling tool is provided for pulling the lead connector assembly proximally in the bore of said connector block from a first position in which the lead's connector assembly is not fully inserted in the connector block to a second position in which said connector assembly is fully inserted in the connector block, the pulling tool being provided with a mechanical connector which engages with mechanical connector on the lead's connector assembly.

Abstract: A method of and apparatus for delivering ventricular pacing pulses to terminate high rate atrial tachyarrhythmias including fibrillation or flutter or to reduce the requirements for termination of atrial fibrillation or flutter. In response to detected atrial fibrillation or flutter, the apparatus delivers ventricular pacing pulses at a lower rate, for example one third or half of the preceding base pacing rate, for a defined, limited period of time. After delivery of the low rate ventricular pacing pulses for the defined time period, if the high rate atrial tachyarrhythmia is not terminated, an additional therapy such a high energy defibrillation pulse or pacing level pulse trains may be applied to the atria. Prior to the delivery of low rate ventricular pacing pulses, the apparatus may deliver a higher rate of ventricular pacing pulses, for example twice the preceding base pacing rate, so that the transition in rates occurring on delivery of the low rate pulses is made more pronounced.

Abstract: In an endocardial, active fixation, screw-in lead of the type having a fixation helix adapted to be rotated in a first, advancement direction out of an electrode head chamber and into cardiac tissue by rotation of a lead connector end and attached lead conductor with respect to an insulating sheath in the first direction and retracted into the chamber by rotation of the lead connector in the opposite, retraction direction, a retraction stop mechanism for preventing over rotation of the helix in the retraction direction. The rotational motion of the lead conductor is transmitted to the helix by a connecting assembly and is translated into axial advancement and retraction of the helix by a guide cooperating with the helix turns. A retraction stop mechanism stops rotation of the helix in the retraction direction upon full retraction of the helix into the chamber and allows rotation of helix in the advancement direction.

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: 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.