Abstract: A method, system and device for implanting an electrode assembly of an implantable medical device in a patient's heart. Positioning one or more radiopaque markers in a coronary sinus of the patient's heart. Positioning, by using the one or more positioned radiopaque markers as a fluoroscopic visual reference, a distal tip of a delivery catheter within a right atrium of the patient's heart so that a distal opening of a lumen of the catheter is against a septal wall of the heart at a location between the ostium of the coronary sinus and the A-V nodal area of the right atrium, and so that the tip of the catheter is generally directed toward a left ventricle of the patient's heart. Advancing the electrode assembly through the lumen of the catheter and into the septal wall.

Abstract: Systems, methods and devices for delivering stimulating energy with a lead having a directional electrode are disclosed. The lead includes a directional electrode having an electrically active portion configured to emanate stimulating energy from an exposed portion of the directional electrode. The lead also has an electrically insulating portion around at least part of the circumference of the lead. The electrically insulating portion is configured to insulate surrounding muscle and/or tissue from the stimulating energy when the lead is implanted in the patient.

Abstract: A method, system and device for monitoring and treating conditions of a mammalian heart, among which may include bradyarrhythmias, tachyarrhythmias and heart failure, the device being configured as a pacemaker that harvests energy as it implements the pacemaker functions to treat and monitor conditions of the heart. The pacemaker has a case, electrical circuitry sealed within the case, an electrode that is electrically coupled to the electrical circuitry, and embodiments may include a microelectromechanical system (MEMS) for harvesting and converting the kinematic energy of the heart into electrical energy. Embodiments provide receivers at locations of the heart which sense heart activity and are controlled with pacing circuitry to deliver electrical impulses at locations and time intervals to replicate the contractions of a normal functioning heart. Further embodiments provide a multi-part pacemaker where case-connectable electrode part may be implanted separately from the case part.

Abstract: Systems, methods and devices to facilitate insertion of a lead for cardiac therapy into an intercostal space associated with the cardiac notch of a patient are described including devices, methods and medical procedure templates to facilitate insertion proximate to a lateral margin of the patient's sternum.

Abstract: A system and method for implanting a ventricular assist device (“VAD”) within the heart includes one or more tools, each having a tool body with a passage. Each tool body can be engaged with an anchor ring assembly secured to the heart. A coring tool can be advanced through the passage in a tool body and used to form a hole in the heart wall, and then valve actuating elements carried on the tool can be used to close a valve incorporated in the anchor ring assembly. A VAD can be passed into the heart through a passage in a tool body after opening the valve. The procedure can be performed while the heart continues to beat, without gross blood loss.

Abstract: A fixation member component, for example, employed by a relatively compact implantable medical device, includes a plurality of fingers; each finger includes a first segment extending from a fixed end of the corresponding finger, and a second segment extending from the corresponding first segment to a free end of the corresponding finger. Each first segment is elastically deformable from a relaxed to an extended condition, and from the relaxed to a compressed condition, and includes a peripheral portion and a central cut-out portion, framed by the peripheral portion. In the compressed condition, a free tip of the cut-out portion of some or all of the fingers may lodge against opposing tissue surfaces, via a spring force of the compressed fingers. Each second segment and cut-out portion is preferably configured to prevent penetration thereof within tissue at the implant site.

Abstract: A method and system for assessing electrode-tissue contact before the delivery of ablation energy. The system may include a control unit programmed to determine a difference between a maximum impedance magnitude at a low frequency for a given electrode and an absolute minimum impedance magnitude at the low frequency across all electrodes, determine a difference between a maximum impedance magnitude at a high frequency for a given electrode and an absolute minimum impedance magnitude at the high frequency across all electrodes, and determine a difference between a maximum impedance phase at the high frequency for a given electrode and an absolute minimum impedance phase at the high frequency across all electrodes. Differences may be correlated to one another using a linear model, the results determining electrode-tissue contact status. The results may be displayed in a graphical format for easy communication to the user.

Abstract: A method and system for assessing electrode-tissue contact before the delivery of ablation energy. The method may generally include determining a difference between a maximum impedance magnitude at a low frequency for a given electrode and an absolute minimum impedance magnitude at the low frequency across all electrodes, determining a difference between a maximum impedance magnitude at a high frequency for a given electrode and an absolute minimum impedance magnitude at the high frequency across all electrodes, and determining a difference between a maximum impedance phase at the high frequency for a given electrode and an absolute minimum impedance phase at the high frequency across all electrodes. These differences may be correlated to one another using a linear model, the results of which determining whether the given electrode is in contact or not in contact with tissue.

Abstract: Catheter devices for ablation and removal of occlusions from blood vessels and methods of using the same are provided. Catheter devices are useful to ablate, cut, dislodge, and otherwise remove occlusions within a blood vessel that may limit or prevent proper circulation. Distal features of the catheter devices comprise arrangements of laser ablative or mechanical cutting features that generally provide enhanced surface areas and cutting functions. Spiral or helical arrangements are provided to aid in cutting operations.

Abstract: Embodiments described herein provide devices, systems, and methods that reduce the distance between two locations in tissue, often for treatment of congestive heart failure. For example, an anchor of an implant system may, when the implant system is fully deployed, reside within the right ventricle in engagement with the ventricular septum. The anchor may be deployed into the heart through a working lumen of a minimally invasive access tool. The minimally invasive access tool may have a plurality of grippers near a distal end of the working lumen. The grippers may engage epicardial tissue of the heart and may be moved radially inwardly relative so as to provide stabilization of the epicardial tissue and/or hemostasis near an access site where the anchor is inserted through the epicardium. The minimally invasive access tool may minimize blood loss from the access site and improve anchor implant processes.

Abstract: This invention is a retinal electrode array assembly and methods of using the same that facilitate surgical implant procedures by providing the operating surgeon with visual references and grasping means and with innovations that reduce actual and potential damage to the retina and the surrounding tissue.

Abstract: Embodiments include a medical implant including a fixing device with at least one fixing element to fix the implant at a site of implantation. The implant includes a belt drive that rotates an actuation device, wherein the actuation device is coupled to the fixing device and converts the rotary movement into a longitudinal movement of the fixing device. Embodiments include an insertion device to insert the medical implant.

Abstract: Embodiments of the present invention generally relate to epicardial heart rhythm management. In some embodiments a method is provided for managing heart rhythm by implanting a pa device within the pericardial space of a patient. In some embodiments, an implantable device is provided for pacing the epicardial surface of a patient. The device may include a first module coupled to a second module by a tether. The first and second modules may be selectively placed for bi-ventricular pacing or for dual chamber pacing in some embodiments. Optionally the modules may be separate and may wirelessly communicate with one another and may also communicate with a heart stimulation device programmer. Optionally, a plurality of devices may be implanted in the pericardial space. A delivery device for delivering the implantable device to the pericardial space is also provided. Further embodiments provide implant retrieval devices and methods.

Abstract: The present invention includes devices and methods for lead or conduit placement in tissues or organs. The devices include a lead or conduit placement device that is configured to permit the placement foot, such as a suction foot, to swivel to a desired position with respect to the target tissue, while the lead is releasably attached to the placement foot to permit it to be released from the placement foot after fixing the lead or conduit in the tissue.

Abstract: Systems, apparatuses, and methods for differentiating between multiple leads that are implanted within a patient include a stimulator configured to be implanted at an implant site within the patient and generate electrical stimulation current, a plurality of leads each comprising one or more electrodes configured to deliver the electrical stimulation current at a stimulation site within the patient, and a shuttle assembly having a plurality of receiving ports each configured to receive a proximal portion of one of the leads and guide the leads from the stimulation site to the implant site of the stimulator. The shuttle assembly is configured to enable a user to differentiate between each of the leads after the leads are guided to the implant site of the stimulator.

Abstract: A device comprising: a lead extending between a proximal end and a distal end, the lead comprising, at its distal end portion, an electrode element configured for fixing in a first body tissue, the lead further comprising: an anchoring element disposed between the proximal and the distal end for anchoring the device to a second tissue; and an elastic element disposed between the anchoring element and the distal end and configured so as to permit the pulling of the distal end away from the anchoring element against the biasing force of the elastic element.

Abstract: A medical implantable lead comprises a conduction controlling means, which at least during an initial stage after implantation is capable of rendering a first contact surface electrically inactive and which is capable of rendering the first contact surface electrically active after the initial stage. By means of the inventive lead it is possible to detect whether the helix is sufficiently screwed into the tissue or not.

Abstract: A medical device for placing a medical lead in the human body using minimally invasive techniques is described. One lead includes a lead body connected to a lead head having an aperture for providing fiber optic access to the interior of a helical electrode. The fiber optic shaft may be disposed within or along-side a drive shaft releasably coupled to the lead head to rotate the head. The drive shaft and lead body may be delivered using a delivery catheter. The delivery catheter can be advanced though a small incision to the target tissue site, and the site remotely visualized through the fiber optic scope extending through the lead head aperture. The lead head can be rotated, rotating the helical electrode into the tissue, and the catheter, drive shaft, and fiber optic probe removed.

Abstract: A guiding accessory, for use in conjunction with a guidewire and a catheter of an implant system, facilitates passage of an elongate and flexible conductor of a relatively compact therapy delivery device to an implant site, for example, within the cardiac venous system, when a therapy generator of the device is held within a distal portion of the catheter, and the catheter, device and guiding accessory are advanced along the guidewire. The guiding accessory includes a helically extending wall that forms a lumen within which the device conductor and guidewire extend. After advancing the catheter, guiding accessory and device to the implant site, the helically extending wall is unwound from around the device conductor, for removal, preferably, by pulling proximally on a tension line, which is attached to a proximal end of the wall.

Abstract: A device for electrical stimulation of the brain, heart, and other neurons and muscles, capable of modifying the electrical activity of its environment in ways that are desirable for a better life style of a patient with brain, heart, or other problems. When used for brain stimulation, the device is able to superimpose an electrical current on the natural current that happens to occur, when the natural currents cause some undesirable effect, as in Parkinson's disease. When used for heart stimulation, the device is able to superimpose an electrical current on the natural current that happens to occur, originating at the sino-atrial node, which causes a healthy heart to pump blood to the lungs and to the body. The device offers an improvement over prior art of being capable of adjusting the position of the stimulating electrodes.

Abstract: An implantable battery powered leadless pacemaker or biostimulator is provided that may include any of a number of features. One feature of the biostimulator is that it safely operates under a wide range of MRI conditions. One feature of the biostimulator is that it has a total volume small enough to avoid excessive image artifacts during a MRI procedure. Another feature of the biostimulator is that it has reduced path lengths between electrodes to minimize tissue heating at the site of the biostimulator. Yet another feature of the biostimulator is that a current loop area within the biostimulator is small enough to reduce an induced current and voltage in the biostimulator during MRI procedures. Methods associated with use of the biostimulator are also covered.

Abstract: The catheter device comprises a motor located at the proximal end of the catheter device and a drive shaft, extending from the proximal end section to the distal end section of the catheter device, for driving a rotating element located at the distal end of the catheter device. The catheter device also comprises a hose-like catheter body which encompasses the drive shaft and extends from the proximal end section to the distal end section of the catheter device. At the proximal end of the catheter device, the drive shaft is connected to a motor by a clutch. The clutch is a magnetic clutch with a proximal and a distal magnet unit. The proximal magnet unit is connected to the motor and the distal magnet unit to the drive shaft. The distal magnet unit is mounted fluid-tight in a clutch housing. The proximal end of the catheter body makes a fluid-tight connection with the clutch housing.

Abstract: A method, system, and apparatus are provided for an electrode assembly comprising a plurality of electrodes for use with an implantable medical device for conducting an electrical signal between the implantable medical device and a target tissue. The electrode assembly includes a helical member and first and second electrodes formed upon the helical member. The first and second electrodes are adapted to deliver the electrical signal. The electrode assembly also includes a first conductive element formed upon the helical member and operatively coupled to the first electrode. The electrode assembly also includes a second conductive element formed upon the helical member and operatively coupled to the second electrode.

Abstract: In a medical implantable lead of the type adapted to be implanted into a human or animal body for monitoring and/or controlling of an organ inside the body and a method for connecting such a lead to an organ in the human or animal body. The lead has a fixation arrangement at a distal end, and the fixation arrangement is adapted to penetrate into the tissue of the organ to fixate the lead to the organ. An electrode member is provided to receive and/or transmit electrical signals from or to the organ. The electrode member is resiliently pre-strained toward the distal end of the lead and is provided with an electrode surface such that the electrode surface will resiliently abut toward the outer surface of the organ when the fixation arrangement is fixed to the tissue.

Abstract: A lead delivery system for delivering a neurostimulation lead to a patient's internal jugular vein using a percutaneous stick. The system comprises a neurostimulation lead adapted to stimulate a vagus nerve from the internal jugular vein. The lead includes a proximal end, a distal end, a generally spiral shaped retaining structure interposed between the proximal and distal ends and configured to retain the lead in the internal jugular vein, an electrode coupled to the retaining structure, and a side port interposed between the retaining structure and the proximal end. The side port provides access to a lumen extending from the distal end to the side port. A guidewire is sized to fit within the side port and lumen and reduce a force exerted by the retaining structure against the internal jugular vein, thereby allowing rotation of the lead and orientation of the electrode by applying a torque to the lead.

Abstract: A lead system has an elongate body, an active fixation assembly movable relative to the elongate lead body, including a non-stationary electrode. The lead system further includes a non-stationary electrode member and an electrical interconnect electrically connected between the non-stationary electrode member and the stationary electrode member. The electrical interconnect provides a reliable electrical interconnection between the stationary electrode and the non-stationary electrode, while allowing the non-stationary electrode to move relative to the stationary electrode.

Abstract: A medical electrical lead for transvascularly stimulating a nerve, muscle or other tissue from an adjacent vessel is described. The lead includes an expandable distal portion having one or more spirals for securing and stabilizing the lead within the vessel.

Abstract: This document discusses, among other things, a lead body extending longitudinally along a lead axis, a driver axially displaceable relative to the lead body, and a driven member coupled to the lead body and displaceable away from the lead axis. The driven member at least partially defines an expandable passage having at least one internal dimension. The driver is displaceable into the expandable passage and has at least one outer dimension that is larger than the at least one internal dimension of the expandable passage. An example method includes disposing a first member having a first cross-section in a lead assembly having a lead axis, an expandable passage, and a displaceable member proximate the expandable passage. The method further includes urging the first member into the expandable passage in the lead assembly, and urging the displaceable member away from the lead axis to expand the expandable passage.

Abstract: An implantable medical lead is disclosed herein wherein the lead employs a helical distal tip anchor having improved fixation capabilities. The implantable medical lead may include a body and a helical anchor. The body may include a distal end and a proximal end. The helical anchor may be at least one of extending and extendable from the distal end. The helical anchor may include at least one loop including first and second straight sides that intersect at a first corner.

Abstract: A medically implantable lead configured for insertion into a human or animal body to be attached in the body with its distal end to tissue inside the body, as a rotatable helix at a distal end thereof that can be screwed into the tissue. The helix serves as an attachment of the lead to the tissue as well as a conductor for conducting electrical signals to the tissue through electrically conducting surfaces on the helix. The surfaces of the helix are partly insulated so as to restrict the conducting of signals between the helix and the tissue to desirable regions. The surfaces of the helix facing inwardly, toward an inner bore of the helix, are electrically insulated. In a method for manufacturing such a lead, the wire forming the helix has protrusions in desired areas and the wire including the protrusions is coated with an electrically insulating layer. The protrusions are uncovered from the insulating layer in desired regions.

Abstract: Methods and systems for transvenously accessing the pericardial space via the vascular system and atrial wall, particularly through the superior vena cava and right atrial wall, to deliver treatment in the pericardial space are disclosed. A steerable instrument is advanced transvenously into the right atrium of the heart, and a distal segment is deflected into the right atrial appendage. A fixation catheter is advanced employing the steerable instrument to affix a distal fixation mechanism to the atrial wall. A distal segment of an elongated medical device, e.g., a therapeutic catheter or an electrical medical lead, is advanced through the fixation catheter lumen, through the atrial wall, and into the pericardial space. The steerable guide catheter is removed, and the elongated medical device is coupled to an implantable medical device subcutaneously implanted in the thoracic region. The fixation catheter may be left in place.

Abstract: In a method and device for mounting an elongated member inside an elongated, elastic, flexible tubing, initially having an inside cross-sectional dimension that is approximately equal to or less than the outside cross-sectional dimension of the elongated member, the inner cross-sectional dimension of the flexible tubing is expanded by applying a pressurized fluid to the inner bore of the tubing, and inserting the elongated member into the tubing while the pressurized fluid is being applied.

Abstract: A medical electrical lead for transvascularly stimulating a nerve, muscle or other tissue from an adjacent vessel is described. The lead includes a bifurcated distal portion including a first elongate member forming a first spiral and a second elongate member forming a second spiral. The spirals can be in parallel or serial alignment with one another.

Abstract: A coiled member of a medical device extends along a length of an elongate body of the device. A surface of the coiled member extends at an angle, with respect to a longitudinal axis of the body, from a first edge to a second edge, toward the proximal end of the body, such that the first edge of the surface is disposed in close proximity to the body and the second edge of the surface is spaced apart from the body.

Abstract: Minimally invasive introducers and methods that can be used for rotationally securing devices within the human body. Introducers can include a distal element for releasably engaging a lead head controllable from a proximal control located outside of the body. An inner stem can extend between a proximal portion and a distal portion, and be pivotally and rotatably coupled to the distal lead engagement mechanism. An outer tube can be rotatably disposed over the inner stem and be flexibly coupled over the pivot to rotationally drive the distal element. A helical epicardial-myocardial lead electrode can be secured and oriented straight ahead and introduced through a port or small incision with the introducer in a straight configuration. The introducer can then be bent and rotated to screw the helical electrode into the heart.

Abstract: A method for inserting a lead electrode into body tissue using a rotatable lead introducer is described. The introducer can include a distal element for releasably engaging a lead head controllable from a proximal control located outside of the body. An inner stem can extend between a proximal portion and a distal portion, and be pivotally and rotatably coupled to the distal lead engagement mechanism. An outer tube can be rotatably disposed over the inner stem and be flexibly coupled over the pivot to rotationally drive the distal element. A helical epicardial-myocardial lead electrode can be secured and oriented straight ahead and introduced through a port or small incision with the introducer in a straight configuration. The introducer can then be bent and rotated to screw the helical electrode into the heart.

Abstract: A medical electrical lead includes a proximal insulation segment, a distal insulation segment, a conductor extending within the proximal and distal segments, and an electrode coupled to the conductor and disposed in proximity to a distal end of the distal insulation segment. A fixation element of the lead is coupled to a distal end of the proximal insulation segment and includes a wire wound in a helix, which extends distally from the proximal segment, over the distal insulation segment.

Abstract: Devices and methods for placing medical leads using minimally invasive techniques. One lead includes a lead body connected to a lead head having an aperture for providing fiber optic access to the interior of a helical electrode. The fiber optic shaft may be disposed within or along-side a drive shaft releasably coupled to the head to rotate the head. The drive shaft and lead body may be delivered using a delivery catheter. The delivery catheter can be advanced though a small incision to the target tissue site, and the site remotely visualized through the fiber optic scope extending through the lead head aperture. Some catheters include a distal mapping electrode readable from the catheter proximal portion or handle. The lead head can be rotated, rotating the helical electrode into the tissue, and the catheter, drive shaft, and fiber optic probe removed.

Abstract: A cardiac lead includes a lead body that defines a passage, a conductive element that extends through the passage, and a fixation assembly. The fixation assembly includes a threaded member threadably engaged with the conductive element such that rotation of the threaded member causes the threaded member to translate longitudinally relative to the conductive element. A fixation element has a first end coupled to the threaded member and a second end coupled to a fixed location. A resilient membrane extends over the fixation element such that rotation of the threaded member affects the resilient membrane radially with respect to the conductive element.

Abstract: A gastro-electric stimulation system includes an INS for producing an electrical stimulation signal, at least one medical electrical lead, and at least two electrical contacts. The medical electrical lead has a proximal end and a distal end, the proximal end being connected to the INS, the distal end being adapted for placement in or near a patient's stomach or appropriate nerve or nerve portion. The electrodes are disposed near the distal end of the medical electrical lead, and are electrically connected through the medical electrical lead to the INS to receive the electrical stimulation signal and convey such signal to the selected electrode implant position. The electrical stimulation signal is provided in an amount and manner adapted to increase the pH of the gastric acid in the patient's stomach and/or to decrease the amount of gastric acid produced thereby.

Abstract: A method for routine monitoring and quality assurance of field asymmetry of high energy circular radiation beam producing equipment. The quality assurance process of field symmetry for devices such as stereotactic radiosurgery (SRS) systems is simplified by directly measuring the integration of the half-beam profile. The method of the invention provides that the field symmetry is obtained by positioning the tip of an ion chamber, with a collecting length approximately half the diameter of the beam, at the central axis of the beam, and rotating the ion chamber at varying angular positions, acquiring and comparing readings at desired angular positions. Each pair of readings from positions 180 degrees opposed from each other, are plugged into the equation, Asymmetry=2(R1?R2)/(R1+R2) to compute asymmetry.

Abstract: The invention is directed to devices for two minimally invasive therapeutic procedures, particularly for patients with congestive heart failure. One procedure involves providing a valve to form a passageway through the patient's left ventricular wall at the apex of the patient's heart and configured to advance instruments through the valved passageway to connect the valve leaflets of the patient's heart valve, e.g. the mitral valve, in a “Bow-Tie” configuration to prevent or minimize regurgitation through the valve. The second procedure is directed to a pacing lead with a housing and a pacing lead implanting device which are configured to pass through a trocar in the patient's chest and implanting the pacing lead on an exposed epicardial region of the patient's heart wall. The pacing lead has a penetrating electrode which is secured within the heart wall. One or both procedures may be performed on a patient with CHF.

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: According to embodiments of the present invention, a cardiac lead system adapted for fixation to a vessel including an expandable fixation mechanism adapted to engage an inner surface of the vessel and a lead member comprising an anchor structure at distal end, the anchor structure configured to removably engage with fixation mechanism. Such anchor structure may be helical, and may removably engage fixation mechanism upon rotation or an application of torque, and may be extendable and/or retractable. Fixation mechanism may be polymer coated weave and/or mesh to trap anchor structure. Lead member and/or fixation mechanism may include electrodes and/or sensors, and lead member may include L-shape, S-shape, spiral, and/or sinusoidal shape for positioning of electrodes and/or sensors or for facilitated engagement of anchor structure. A guide wire attached to fixation mechanism during deployment may, prior to detachment, serve to guide lead member to a target site at fixation mechanism.

Abstract: Lead placement apparatus to transmit electrical signals to stimulate selected body tissue includes an introducer handle supporting a tubular outer sheath of flexible resilient material including a rigid section and a deflectable section adjacent the distal end, enabling the deflectable section to deflect among a plurality of positions in orientations transverse of a longitudinal axis. An operative member on the introducer handle connected to the distal end of the outer sheath serves to move that distal end. An inner tubular sheath of flexible resilient material slidably received within the outer sheath includes a driving socket fixed to its distal end whereby, with a lead slidably received within the inner tubular sheath and including a driven socket fixed to its distal end for releasable mating engagement by the driving socket, an electrode at the distal tip of the lead can be advanced and directed to the selected body tissue for stimulation.

Abstract: A method and apparatus for placing an epicardial lead over a desired, predetermined location on the left ventricle using a minimally invasive approach. A thoracoscope having a handle portion and a probe tube defining a central opening is placed through an incision in the patient generally aligned with the desired position for the pacing lead. An introducer and pacing lead are placed within the central opening of the thoracoscope and moved into contact with the pericardium at the desired lead location. An attachment member of the pacing lead attaches an electrode of the pacing lead to the pericardium. The pacing lead includes a mesh disk surrounding the electrode to aid in long term attachment of the electrode to the heart. Alternatively, the pericardium can be incised such that the lead is placed directly over the epicardial surface of the left ventricle.

Abstract: The lead body of a medical lead comprises a distal end portion carrying at least one electrode for placement in the pericardial sac of a human heart. The distal end portion of the lead body includes a multi-turn section having opposed ends, opposing forces applied to the ends tending to flatten the multi-turn section, the multi-turn section being thereby adapted to be retained within the pericardial sac. The turns of the multi-turn section may become progressively smaller from one end of the section to the other end of the section. The multi-turn section may have, in a relaxed state thereof, a generally conical, helical configuration. The at least one electrode may be carried adjacent to the end of the multi-turn section having the larger turns. Alternatively, the at least one electrode may be carried adjacent to the end of the multi-turn section having the smaller turns.

Abstract: Improved pacing thresholds for capturing the heart are achieved by forming a discontinuity in the cardiac tissue of the heart chamber, disposing a pacing electrode at a distance less than a space constant of the cardiac tissue from the discontinuity in the cardiac tissue, and applying a stimulus of a first polarity at an energy insufficient to cause the directly stimulated tissue adjacent to the pacing electrode to propagate a depolarization wave through the cardiac tissue mass of the heart chamber but sufficient to induce a transmembrane potential change at the tissue adjacent to the discontinuity that results in a propagated wave front. Thus, pacing energy is advantageously reduced.

Abstract: Improved pacing thresholds for capturing the heart are achieved by forming a discontinuity in the cardiac tissue of the heart chamber, disposing a pacing electrode at a distance exceeding a space constant of the cardiac tissue from the discontinuity in the cardiac tissue, and applying a stimulus of a first polarity at an energy insufficient to cause the directly stimulated tissue adjacent to the pacing electrode to propagate a depolarization wave through the cardiac tissue mass of the heart chamber but sufficient to induce a transmembrane potential change at the tissue adjacent to the discontinuity that results in a propagated wave front. Thus, pacing energy is advantageously reduced.

Abstract: An epicardial screw-in lead is disclosed which includes an elongated lead body, an electrode housing at a distal end of the lead body for stimulating cardiac tissue, and a helical fixation screw within the electrode housing which can be extended to affix the electrode housing to the cardiac tissue. Preferably at least a portion of the helical fixation screw is electrically active. A lead implantation kit is also disclosed that can include the screw-in lead, a screwdriver tipped stylet for activating the screw, and a flexible guiding sheath for directing the tip of the stylet to the electrode housing.