Abstract: A method is provided, including implanting in an atrial wall of a subject, from within an atrium, a first electrode contact in a vicinity of a parasympathetic epicardial fat pad of the subject, and implanting a second electrode contact in a body of the subject outside of a heart and a circulatory system. A current is driven between the first and second electrode contacts, and configured to cause parasympathetic activation of the fat pad. Other embodiments are also described.

Abstract: An atrial ablation catheter with an electrode array particularly adapted to locate and ablate foci of arrhythmia which are required for sustained atrial fibrillation is provided. The array is easily deployed and retracted from the catheter, and presents a proximally oriented electrode array that can be pulled against the septal wall of the left atrium to engage the septal wall.

Abstract: Implantable hermetically sealed structures and methods for making the same are provided. Also provided are devices, systems and kits including the hermetically sealed structures, as well as methods of using such devices and systems.

Abstract: An implantable lead is disclosed which includes an elongated lead body having opposed proximal and distal end portions. At least one defibrillation assembly is operatively associated with the distal end portion of the lead body for delivering electrical energy to cardiac tissue. The defibrillation assembly includes a plurality of axially spaced apart conductive hull assemblies that at least partially surround the elongated lead body, and a helically wound shocking coil that extends over the axially spaced apart hull assemblies so that a series of annular void regions are defined by the shocking coil, the lead body, and adjacent hull assemblies, whereby the annular void regions allow the shocking coil to articulate, thereby inhibiting buckling of the shocking coil.

Abstract: An epicardial pacing lead including a flexible, elongated lead body. The epicardial pacing lead has a proximal end and a distal end. An electrode is coupled to the lead body near the distal end. A housing is coupled to the lead body proximal to the electrode. A platform is at least partially encompassed by the housing. The platform includes at least four tines. Each tine is adapted for engagement with the epicardium and includes an upper section extending outwardly from the platform and a lower section extending distally at an angle to the upper section.

Abstract: A transvenously implantable medical device (TIMD) includes an electrical lead and a control module. The electrical lead includes one or more electrodes and is adapted for transvenous implantation. The electrical lead is also pre-biased to expand from a collapsed state to an expanded state to mechanically engage an internal wall of a blood vessel. The control module is secured to and in electrical communication with the electrical lead. The control module includes a signal management component and a power component disposed in a housing adapted for implantation into the blood vessel. The control module is adapted for at least one of stimulating and sensing a physiologic response using the one or more electrodes of the electrical lead.

Abstract: An apparatus for mapping and/or ablating tissue includes a braided conductive member that that may be inverted to provide a ring-shaped surface. When a distal tip of the braided conductive member is retracted within the braided conductive member, the lack of a protrusion allows the ring-shaped surface to contact a tissue wall such as a cardiac wall. In an alternative configuration, the braided conductive member may be configured with the distal portion forming a proboscis that can be used to stably position the braided conductive member relative to a blood vessel, such as a ventricular outflow tract. The braided conductive member has a plurality of electronically active sites that may be accessed individually for stable mapping over a broad area for stable mapping or ablation to form broad and deep lesions.

Abstract: The disclosure describes a hand-held device that utilizes a mechanical lever system to operate the device with a single hand. The mechanical lever system is coupled to a sliding element within the housing of the hand-held device that slides linearly. The sliding element may be attached to another element that is extended, retracted, or rotated in or out of the device. For example, the hand-held device may be used for prostate ablation therapy. The hand-held device may include an ablation needle electrode that is extended out of a catheter and into a tissue of a patient by depressing an extension lever of the mechanical lever system to deliver ablation therapy. Depressing a retraction lever of the mechanical lever system may retract the needle electrode back into the catheter of the hand-held device. Other variations of the mechanical system and applications of the hand-held device are also described.

Abstract: An implantable medical system that includes an implantable electrical lead having a lead body having a connector portion wherein at least the connector portion of the lead body has an axial cross section that is substantially non-circular; and a connector block that is configured to be operably coupled to the implantable electrical lead, wherein the connector block includes a lumen having an inner surface that is configured to be complementary to the outer surface of at least the connector portion of the lead body. Leads and connector blocks are also discussed.

Abstract: An EP catheter includes a tip electrode having a core primarily comprised of copper with an outer layer of a biocompatible metal disposed thereon exhibits appropriate electrical and thermal conduction characteristics while being cost-effective to produce. Alternatively, an inner layer of a biocompatible metal is disposed on the inside of the primarily copper core. Such a tip electrode may also be provided with irrigation lumens. Such a tip electrode could be manufactured from sheets of metal that upon extrusion would comprise the outer layer, core and optional inner layer respectively.

Abstract: A medical electrical lead includes a lead body and a connector terminal. A conductor extends from the lead body to the connector terminal along a helical path through a transition zone.

Abstract: An atrial ablation catheter and methods for its use. The endocardial catheter includes an electrode array particularly adapted to locate and ablate foci of arrhythmia which are required for sustained atrial fibrillation is provided. The array is easily deployed and retracted from the catheter, and presents a distally oriented electrode array that can be pressed against the wall of the atrium.

Abstract: A system is provided for treating valvular disease percutaneously though a ventricular apex of the heart. The system includes a needle for piercing through the ventricular apex of the heart and creating a hole whereby a catheter can be passed through the skin and the wall of the heart to gain access to the interior of the heart. Once percutaneous access to the heart is obtained, any of a variety of techniques can be utilized for annular and/or valvular therapy and/or repair through the catheter. A closure device is necessary for closing the puncture of the heart. Any of a variety of vascular closure devices can be modified to be utilized with the system to close the puncture of the ventricular apex of the heart.

Abstract: Methods and devices are disclosed for detecting vulnerable atherosclerotic plaque, or plaque at risk of reducing blood flow in a vessel, by identifying a region of elevated temperature along a living vessel wall. The disclosure that human atherosclerotic plaque with measurable temperature heterogeneity has the morphological characteristics of plaque that is likely to ulcerate provides a new and sensitive technique for detecting and treating these dangerous plaques before myocardial infarction and its consequences occur. The disclosed methods are advantageous over conventional plaque detection techniques because they are capable of differentiating between those plaques that are at great risk of rupture, fissure, or ulceration, and consequent thrombosis and occlusion of the artery, and those that are not presently at risk. Infrared heat-sensing catheters useful for identifying potentially fatal arterial plaques in patients with disease of the coronary or other arteries are also described.

Abstract: A method for transmyocardial revascularization of the heart of a patient includes positioning an active electrode surface in close proximity to a target site on the wall of a patient's heart, and applying high frequency voltage between the active voltage surface and a return electrode to ablate tissue at the heart wall. The high frequency voltage ablates, i.e. volumetrically removes the heart tissue, and the electrode surface is axially translated into the space vacated by the removed tissue to bore a channel through the heart tissue. The active electrode surface may be introduced into the thoracic cavity and placed adjacent the epicardium to form an inward channel toward the ventricular cavity, or it may be delivered into the ventricular cavity of the heart and positioned adjacent the endocardium to form a channel extending outward towards the epicardium.

Abstract: A method of ablating tissue in the heart to treat atrial fibrillation introduces into a selected atrium an energy emitting element. The method exposes the element to a region of the atrial wall and applies ablating energy to the element to thermally destroy tissue. The method forms a convoluted lesion pattern comprising elongated straight lesions and elongated curvilinear lesions. The lesion pattern directs electrical impulses within the atrial myocardium along a path that activates the atrial myocardium while interrupting reentry circuits that, if not interrupted, would cause fibrillation. The method emulates the surgical maze procedure, but lends itself to catheter-based procedures that do not require open heart surgical techniques. A composite structure for performing the method is formed using a template that displays in planar view a desired lesion pattern for the tissue. An array of spaced apart element is laid on the template.

Abstract: A circumferential ablation catheter is provided, which is particularly useful for treating atrial arrhythmia by ablating a substantial portion of a circumferential region of tissue in a tubular region of or near the heart of a patient. The catheter comprises an elongated tubular catheter body having an outer wall, proximal and distal ends, and at least one lumen extending therethrough. An ablation assembly is mounted at the distal end of the catheter body. The ablation assembly comprises a circumferential ablation element mounted on the distal end of the catheter body, and an inflatable balloon provided in surrounding relation to the circumferential ablation element. The inflatable balloon is adjustable between a radially collapsed position and a radially expanded position. The catheter further comprises a stabilization assembly mounted on the catheter distal to the ablation assembly.

Abstract: This invention is a lead (10) for modifying the activity of a tissue, particularly the heart. Electrodes are provided for performing sensing (15p) (15d), and/or signal delivery (16p) (16d) functions. A control unit controls the parameters of the electric field provided by signal delivery electrodes to prevent the generation of a propagation action potential in the tissue.

Abstract: A seal adapted for use with medical devices is provided with a lead having a distal tip electrode. The distal tip of the lead is adapted for implantation on or about the heart and for connection to a system for monitoring or stimulating cardiac activity. The lead can include a fixation helix for securing the electrode to cardiac tissue. The lead assembly can alternatively include an open lumen lead tip. A seal is provided within the lead tip assembly such that the seal is expanded to prevent or limit further entry of fluids through the lead tip. The seal includes an expandable matrix, such as a hydrogel. The seal is formed on or within the lead when the lead and the seal comes into contact with a fluid and expands. The seal is also formed as a plug which is deployed through the medical device, and expands as the plug absorbs fluid. A housing incorporating the seal can also be attached to a portion of the medical device to provide the seal.

Abstract: A terminal part for an electrode line for connection to an implantable heart stimulator, the terminal part having multiple annular, electrically conductive contacts of equal external diameter having insulation sections of the same external diameter situated between them in the longitudinal direction, of which the electrically conductive contacts are each electrically connected to an electrically conductive terminal line, the terminal part being formed by multiple insulating adapters and by electrical contacts held thereby having terminal lines fastened thereon, which are plugged together and connected using a thermoplastic injection molding compound after being plugged together, the terminal part otherwise being implemented in such a way that it is to be connected as an independent unit to a remaining electrode line.

Abstract: An intravascular lead adapted to be deployed to a stimulation site within a vessel adjacent a nerve to be stimulated includes at least a first electrode adapted to deliver an electrical pulse across a vessel wall. The first electrode includes an electrically active surface having one or more surface features adapted to focus current. The first electrode is disposed on the distal portion that the electrically active surface can be directed towards the nerve to be stimulated.

Abstract: An implantable medical device, such as a lead or lead extension, includes a body having a distal end portion and a proximal end portion configured to be at least partially received by an apparatus. The device further includes a conductive member at the distal end portion of the body and an electrical contact at the proximal end portion of the body. The electrical contact is electrically coupled to the conductive member and is positioned such that, when received by the apparatus, at least a portion of the apparatus is capable of electrically coupling to the electrical contact. The device further includes a reinforcement member integrated in the body.

Abstract: A medical electrical lead for implantation in a patient's internal jugular vein at a target location and adjacent a vagus nerve. The lead comprises a proximal region having a proximal stiffness and a distal region. The distal region has a distal stiffness and a first spiral configured to retain the distal region in the internal jugular vein. A transition region is interposed between the proximal and distal regions and has a transitional stiffness. An electrode is coupled to the distal region. The proximal stiffness is less than the distal stiffness so as to reduce an amount of force transferred from the proximal region to the distal region. The transitional stiffness is less than the distal stiffness and greater than the proximal stiffness.

Abstract: An implantable lead body for a medical device with improved conductor lumens separates and insulates conductors while permitting access to the conductors through the implantable lead outer surface. The implantable lead comprises a lead body, a stylet lumen, at least one conductor lumen, and at least one axial slit in the lead body. The lead body has a proximal end, a distal end, an internal portion, and an external portion. The stylet lumen is formed in the internal portion. The conductor lumen is formed in the internal portion and positioned near an outer surface of the internal portion such that there is only a web between the conductor lumen and the outer surface of the internal portion. The axial slit is formed in the lead body distal end between the conductor lumen and the outer surface of the internal portion.

Abstract: The medical lead delivery device more easily and quickly delivers a lead to or through the coronary vein of a patient's heart. The medical lead delivery device includes an elongated body, a controller, a first and second spring, and a sleeve. The elongated body includes a proximal end and a distal end. The controller is disposed at the proximal end and provides enhanced control of the distal tip of the elongated body.

Abstract: A medical electrical lead includes a lead body and a connector terminal. A conductor extends from the lead body to the connector terminal along a helical path through a transition zone.

Abstract: A lead having an extendable and retractable fixation mechanism has a rotating terminal pin at the terminal end which rotates the fixation mechanism at the distal end. As the terminal pin is rotated, the fixation mechanism is extended or retracted from the distal end of the lead. A threaded collar allows for the fixation mechanism to smoothly extend and retract from the lead, and allows for a 1:1 turn ratio between the terminal pin and the fixation mechanism. A fluoroscopic ring disposed at the distal end of the lead provides information during the implantation process.

Abstract: Medical electrical leads including coil electrodes having polymeric material between but not over the coil turns. Some leads can be used for neurological sensing and/or stimulation applications. The coil electrodes are more flexible, bendable, and stretchable relative to corresponding cylindrical band electrodes. The polymer fill between the coil turns provides more column strength than coil electrodes having empty space between the coil turns. Some leads have a lumen for receiving stiffening members while others do not have such lumens. An introducer needle can be used to introduce a steerable sheath containing the lead. The sheath and lead can be advanced to near the target site and the sheath removed. The present invention can be used to advantage in peripheral nerve and other applications. Some leads are made by masking the coil electrode outer surface with heat shrink material and filling the coil inter-strand regions with polymer.

Abstract: A heart stimulator provides a reliable automatic capture threshold search feature. A stimulation pulse generator is connected to at least a ventricular stimulation electrode for delivering electric stimulation pulses to at least the ventricle of the heart. The stimulation pulses generated have a strength depending on a control signal. A sensing stage is connected to an electrode for picking up electric potentials inside at least said ventricle of a heart and a control unit connected to the sensing stage and to the stimulation pulse generator determines points of time for scheduling stimulation pulses, to trigger the stimulation pulse generator so as to deliver a stimulation pulse when scheduled and to put out control signals for controlling the strength of the stimulation pulse. The control unit is further adapted to perform a capture analysis which may take into account extraordinary events.

Abstract: An apparatus for delivering energy to tissue, comprising an elongate flexible shaft having a proximal end and a distal end; a sheath disposed over at least a portion of the flexible shaft; a resilient housing near the distal end of the flexible shaft, the housing adapted to deflect so as to appose the tissue; and at least one electrode mounted to the distal housing; an elongated pusher coupled with one of the housing and the at least one electrode and adapted to deflect the at least one electrode into apposition with the tissue.

Abstract: A medical electrical lead, which may be useful in coupling an implantable medical device, is comprised of a first and second lead. The first lead has a first electrode coupled adjacent a distal end portion thereof. The distal end portion of the first lead is anchorable in the coronary sinus of a patient. The second lead is coupled with and moveable along the first lead. The second lead has a second electrode located thereon wherein the position of the first and second electrodes may be varied relative to one another by movement of the second lead along the first lead. A rubber tip holds the relative position of each electrode.

Abstract: A lead assembly for an implantable medical device. The lead assembly comprises a lead body having a first portion and a second portion. The first portion is adapted for coupling to a pulse generator and the second portion is adapted for implantation in or near a heart. First and second co-radial conductive coils are positioned within the lead body and electrically isolated from each other. The first and second conductive coils include a first and second number of coil turns and the first number is substantially equivalent to the second number. A ring electrode is located at the second portion and a tip electrode is located distal to the ring electrode and coupled to the second conductive coil. The first conductive coil extends past the ring electrode and transitions to a non-coiled region, which extends back to and couples to the ring electrode.

Abstract: Medical lead systems utilizing electromagnetic bandstop filters are provide which can be utilized in a magnetic resonance imaging (MRI) environment for patients who have implanted medical devices. Such lead systems may be advantageously used in left ventricle cardiac stimulation systems, neuro-stimulation systems, and deep brain electrodes used for the treatment of Parkinson's disease and other movement disorders. The bandstop filters, which include a tuned parallel capacitor and inductor circuit, are backwards compatible with known implantable deployment systems.

Abstract: An implantable medical assist device includes a medical device. The medical device has a housing and electronics contained therein. A lead provides an electrical path to or from the electronics within the medical device. A resonance tuning module is located in the housing and is connected to the lead. The resonance tuning module includes a control circuit for determining a resonant frequency of the implantable medical assist device and an adjustable impedance circuit to change the combined resonant frequency of the medical device and lead.

Abstract: A bipolar pacing and sensing lead incorporates a range of active surface areas for each of the anode and cathode electrodes, and a range of inter-electrode spacings between the anode and cathode electrodes which, in combination, provide acceptable near-field signal amplitudes and attenuate the amplitudes of unwanted signals, such as far-field R-waves, far-field P-waves, and T-waves.

Abstract: A stylet unit is provided for implanting in a body, with the aid of an earlier installed tubular delivery sheath having a lumen with an inner diameter, a lead system including a distal electrode for an implantable cardiac stimulation device being slidably received in the lumen of the introducer device. An elongated main member is engageable with a thrusting region of the lead for advancing the distal electrode to a desired body stimulation site and an integral resilient knob at a proximal end serves to manipulate the main member. The knob has a nominal outer dimension greater than the inner diameter of the delivery sheath lumen and is compressible in directions transverse of the longitudinal axis. The delivery sheath can be slidably advanced across the knob which becomes compressed, enabling its continued slidable transit across the knob and, eventually, free of the lead system and of the stylet unit.

Abstract: According to one aspect of the invention, a method of forming a medical device is provided, which includes: (a) contacting a substrate with a solution that contains (i) one or more types of polymers, (ii) a solvent that contains one or more types of solvent species, and (iii) one or more optional agents, for example, one or more therapeutic agents, among others; and (b) removing the solvent from the solution, thereby forming a polymeric layer on the substrate. The composition of the solution is changed over the course of forming the polymeric layer. In another aspect of the invention, a medical device is provided, which includes a substrate and a polymeric layer over the substrate. The polymeric layer contains a copolymer that contains differing first and second monomers. The lower surface of the polymeric layer contacting the substrate has a surface concentration of the first monomer relative to the second monomer that is higher than that of the upper surface of the polymeric layer opposite the substrate.

Abstract: An implantable myocardial stimulation lead comprises a lead body having a distal end and a proximal end, and an electrical connector carried by the proximal end of the lead body. An electrode header carried by the distal end of the lead body has an axis and includes a helical fixation element extending along the axis, the electrode header having a surface configured to receive a driver for rotating the electrode header to screw the helical fixation element into the tissue of the heart. The lead body carries along its length a strain relief member resisting excessive bending of the lead body.

Abstract: Methods for treating anatomic tissue defects such as patent foramen ovale (PFO) generally involve positioning a distal end of an elongate catheter device at the site of the anatomic defect, exposing an expandable housing and energy transmission member out of the distal end of the catheter device, engaging the housing with tissues at the site of the anatomic defect, applying suction to the tissues via the housing to bring the tissues together; and applying energy to the tissues with the energy transmission member to substantially close the anatomic defect acutely. Apparatus generally include an elongate catheter body, a housing extending from a distal end of the catheter body for engaging tissues at the site of the anatomic defect, and an energy transmission member adjacent a distal end of the housing, the energy transmission member having at least one substantially planar surface.

Abstract: A surgical probe and methods for targeted treatment of structures of the heart with heat and radiofrequency energy. The probe which is designed to operated by hand has a elongate member with a handle and an energy-delivering member in an adjustable loop configuration. The control placed on the handle allow the user to alter the length of the loop configuration of the energy-delivering member and to thus place energy-delivering elements located on the energy-delivering member at selected or targeted portions of the heart or structures within the heart. The elongate member is conformable and can be bent into different configurations to allow additional targeted treatment of the particular portions of the heart.

Abstract: Cardiac lead implantation systems and methods including an electronics arrangement provided with a user interface and a coupler assembly. A coupler body is configured to detachably grasp a cardiac lead and couple with electrical contacts of the cardiac lead. A user interface includes an output indicative of sensed cardiac parameters, such as one or both of cardiac signal amplitude and lead electrode impedance, and may include an audio output device and/or a visual output device. Methods of lead implantation involve advancing a cardiac lead into proximity with a patient's heart, and contacting cardiac tissue with an electrode arrangement to locate a suitable implant location. Sensing of one or more cardiac parameters is accomplished and an audible representation of the sensed parameters is produced, the audible representation varying as the electrode arrangement is moved relative to the cardiac tissue.

Abstract: An apparatus for releasably engaging an implantable medical device during delivery includes an elongate, tubular body having an open distal end a plurality of deflectable jaw members extending distally from the distal end of the body and terminating in distal tip portions, and an actuating member slidably disposed within the body and including a distal end portion operable to prevent inward deflection of the jaw members when positioned proximate the distal tip portions. The jaw members are adapted to releasably engage an engagement feature of the implantable medical device.

Abstract: An electrophysiology catheter includes a tube having a proximal end, a distal end, and a lumen therebetween. The tube is preferably comprised of multiple sections of different flexibility, arranged so that the flexibility of the catheter increases from the proximal end to the distal end. There is a first generally hollow electrode member at the distal end. At least one magnetically responsive element is disposed at least partially in the hollow electrode, for orienting the distal end of the catheter with an externally applied magnetic field. Multiple magnets can be distributed over the distal portion of the device. The end electrode can have openings for delivering irrigating fluid, and/or a sleeve can be provided around the tube to create an annular space for the delivering of irrigating fluid. A temperature sensor can be provided to control the operation of the catheter. A localization coil can also be included to sense the position and orientation of the catheter.

Abstract: An implantable apparatus for the detection and monitoring of spontaneous cardiac electrogram features in a comprises a cardiac monitoring device and a plurality of subcutaneous cardiac sensing electrodes electrically connected to the monitoring device. The sensing electrodes are configured for sensing cardiac electrogram features when implanted in spatially separate locations in a patient. A storage device contained within the monitoring device is operably associated with the subcutaneous electrodes and stores the cardiac electrogram features. Preferably, the plurality of subcutaneous electrodes are carried by a single elongate lead. A downloading device such as telemetry apparatus or transcutaneous electrical connectors may be provided so that the stored information can be downloaded to a separate apparatus external to the patient. In a preferred embodiment, the apparataus is a defibrillator. Methods of using such apparatus are also disclosed.

Abstract: An ablating device has a cover which holds an interface material such as a gel. The cover contains the interface material during initial placement of the device. The ablating device may also have a removable tip or a membrane filled with fluid. In still another aspect, the ablating device may be submerged in liquid during operation.

Abstract: Implantable medical lead assemblies that are customizable and that are flexible and extensible in a controllable manner to facilitate subject body movements. In particular, implantable medical lead assemblies in accordance with the present invention advantageously include the ability to be customized by selective and controllable separation of leads from one another, which lead assemblies are also able to permit and withstand multiple degree of freedom that are useful for use in the neck region of a subject body and other regions of any subject's body that may benefit from increased flexibility and extensibility.

Abstract: An implantable lead comprises a lead body extending from a lead proximal end portion to a lead distal end portion. In one example, the lead body may comprise a heat-formed bias portion. In another example, an outer insulator is fused to the lead body. In such an example, a lead body fusable plug may be disposed distal to at least one conductor. In another example, the lead comprises an inner boot and an outer boot fused to one another. In another example, the lead includes an atraumatic tip fused to the lead distal end portion. In another example, the lead body is reducable in size using heat shrink tubing. In yet another example, two or more lead sections may be interconnected using an outer insulator fused to the respective lead bodies. In a further example, a stiffener member is fused to the lead body adjacent a lead component.

Abstract: An intravascular device for the formation of linear lesions which has particular utility in the treatment of atrial fibrillation and flutter. The intravascular device has an outer delivery member with a distal section which has an elongated opening and a support element coextending with the opening. An EP device having a plurality of electrodes on its distal section is slidably disposed within the inner lumen of the delivery member but it is secured by its distal end within the distal extremity of the delivery member at least while in operation. In this manner an axial force in the proximal direction on the proximal extremity of the EP device, which extends out of the patient during the procedure, will cause the distal shaft section of the EP device to arch outwardly out of and away from the distal section of the delivery shaft along an inner side of the curved distal section and engage the surface of the patient's heart chamber.

Abstract: Implantable medical leads that are flexible and extensible in a controllable manner to facilitate subject body movements. In particular, implantable medical leads advantageously are able to permit and withstand multiple degree of freedom that are useful for use in the neck region of a subject body and other regions of any subject's body that may benefit from increased flexibility and extensibility. Preferably, features of medical leads are utilized to permit extensibility and are based upon the provision of shaped features that controllably permit lead extension under low load, but that maintain a desired shape under no load. The shaped lead portions provide extensibility to the lead as the shapes elastically deform under load. Preferably, a shaping element, such as an elongate element or a tube defines and holds the lead in the desired shape, which most preferably comprises one or more series of sigmoid shapes as a pattern.

Abstract: A cardiac lead for placement in the vicinity of a patient's heart is described. The lead includes a self-expanding fixation mechanism, which in a retracted position, is contained within a cavity disposed at a distal end of the lead. In an expanded position, the fixation mechanism extends axially from the distal end of the lead and expands radially into contact with a desired lumen site.