Abstract: Implantable cardiac monitoring and stimulation methods and devices with epicardial leads having sensor feedback. A fixed or extendable/retractable sensor may be displaceable within the lead's lumen and configured to sense the presence of an anatomical feature or physiological parameter of cardiac tissue in proximity with the lead body's distal end. The sensor may include an ultrasonic sensing element, a perfusion sensor, a photoplethysmographic sensor, or a blood oximetry sensor. Methods of determining suitability for implanting a lead involve the steps of accessing an epicardial surface of the heart, and moving the cardiac lead to an implant site at the epicardial surface. A transmitted signal is directed at the implant site. A reflected signal is received, indicative of the presence of a blood vessel at the implant site. A determination may be made to determine whether the implant site is suitable or unsuitable based on the reflected signal.

Abstract: An implantable lead adaptor is disclosed that includes an encapsulated thermoplastic housing defining a proximal end portion and a distal end portion. The proximal end portion has a first receptacle configured to receive a first type of connector assembly associated with a first implantable cardiac lead, and a second receptacle configured to receive a second type of connector assembly associated with a second implantable cardiac lead. An elongated flexible lead portion extends from the distal end portion of the adaptor housing. A connector assembly is operatively associated with a distal end section of the flexible lead portion of the adaptor for connection to an implantable pulse-generating device, such as, for example, an implantable pacemaker or defibrillator. Low resistance conductor wires electrically connect the connector assembly associated with the distal end section of the lead portion with the first and second receptacles of the adaptor housing.

Abstract: A medical lead system includes at least one bandstop filter for attenuating current flow through the lead across a range of frequencies. The bandstop filter has an overall circuit Q wherein the resultant 3 dB bandwidth is at least 10 kHz. The values of capacitance and inductance of the bandstop filter are selected such that the bandstop filter is resonant at a selected center frequency or range of frequencies. Preferably, the bandstop filter has an overall circuit Q wherein the resultant 10 dB bandwidth is at least 10 kHz. Such bandstop filters are backwards compatible with known implantable deployment systems and extraction systems.

Abstract: Methods for ultrasonically joining portions of a medical lead are provided. One method includes providing a conductor, a fitting and a coil electrode. The conductor has a distal portion that includes an inner conductive portion and an outer insulative portion. The fitting has a first cavity and a second cavity, the first cavity being sized and configured to receive the distal portion of the conductor and the second cavity being sized and configured to receive a portion of the coil electrode. The conductor is ultrasonically welded within the first opening, providing a mechanical and electrical attachment. The coil electrode is also electrically coupled to the fitting, providing an electrical pathway from the conductor to the coil electrode. Also provided are medical leads including ultrasonic bonds and other methods of ultrasonically joining portions of a medical lead.

Abstract: A subcutaneous implantable device is provided that includes a defibrillation electrode disposed along a portion of a lead, and a lead tip connected to the lead. The lead tip includes a trailing end coupled to a distal end of the lead, and first and second non-parallel sides extending from the trailing end that converge to a leading end that is configured to wedge between tissue layers as the lead is advanced subcutaneously.

Abstract: A method for attaching a ring electrode to the shaft of the tip section of a catheter comprises passing an electrode lead wire through a lumen in the catheter and out an exit hole in the tip section. The portion of the electrode lead wire extending out of the exit hole is stripped of non-conductive coating and wrapped around the shaft and secured in a clove hitch arrangement. The wrapped electrode lead wire is pulled tight while the material of the shaft is heated to embed the electrode lead wire in the shaft so that its outermost surface is generally flush with the surface of the shaft. The exit hole is sealed and a ring electrode, having a flared skirt is slipped over the shaft to a position over the wrapped electrode lead wire and exit hole. It is then swaged to reduce its outer diameter to about that of the outer diameter of the shaft of the tip section to thereby create a low ohmic connection with the electrode lead wire.

Abstract: A sensor assembly, which may be incorporated by a medical electrical lead, includes an insulative body, formed from a biocompatible plastic, and a sensor mounted on a mounting surface of the insulative body. The mounting surface extends distally from a proximal portion of the insulative body in which first and second conductive inserts extend, being spaced apart and isolated from one another. The sensor is coupled to each of the first and second conductive inserts, and the first conductive insert includes a conductor-coupling end extending proximally from the proximal portion of the insulative body. The sensor assembly may further include an electrode extending around the sensor and the insulative body, wherein the electrode includes an aperture approximately aligned with an active surface of the sensor to expose the active surface. A mounting platform assembly for the sensor assembly may include the conductive inserts and the insulative body.

Abstract: An implantable medical electrical lead for electrical stimulation of body tissue that includes at least one shape memory polymer portion that has a first configuration and a second configuration, wherein the second configuration is obtained upon exposure of the shape memory polymer portion to a transition stimulus, and wherein the second configuration of the modifiable portion exhibits a greater resistance to movement of the lead within the body tissue than does the first configuration; and at least one electrode configured to provide electrical stimulation of body tissue, wherein the lead has a proximal end and a distal end. Systems and kits as well as methods of utilizing the leads of the invention are also included.

Abstract: A method of identifying the fossa ovalis in a patient by positioning one or more electrodes against the tissue of the interatrial septum of the patient and acquiring unipolar and/or bipolar electrograms of the tissue of the interatrial septum while moving the electrodes to a plurality of positions against the tissue of the interatrial septum. The fossa ovalis is identified on the basis of unipolar voltage reduction, signal fractionation, broadened signal, reduced signal slew rate, reduced local myocardial impedance, increased phase angle and/or increased pacing threshold. An apparatus for identifying the fossa ovalis is also provided.

Abstract: An electrode catheter, in particular for cardiac therapy, includes an elongate, tubular catheter body, an electrode for delivering or measuring an electrical signal, in particular an electrocardiac signal, via its external electrode contact surface, at least one first supply line for the electrical connection of the electrode, at least one second supply line for the electrical connection of a further electrode, a plug terminal connection between the at least one first supply line and the electrode, and an insulated passage of the at least one second supply line through the electrode.

Abstract: A transcoronary sinus pacing system comprising a sheath having a lumen, a pacing catheter having a pacing needle, wherein the catheter can be advanced within the lumen and placed in the LV summit, and a right ventricular pacing device. A LV summit pacing device. An early mitral valve closure pacing device configured to operate with a right ventricular apex pacing device. A method for implanting a pacing device at a target coronary sinus tissue location, wherein the target can be the posterior LV summit A method for achieving early closure of a mitral valve. A method for using visualization devices such as fluoroscopy or ultrasound and/or catheter features such as a radiopaque marker to locate a target location for LV pacing and to avoid piercing an artery or the pericardium when anchoring the LV pacing electrode.

Abstract: A catheter assembly comprises a first branch body having a first axis, a second branch body extending in a non-parallel relationship with respect to the first axis, and at least one electrode carried by the second branch body. In use, the first branch body can be located within a pulmonary vein within the left atrium, while the electrode carried by the second branch body is located in contact with endocardial tissue outside the pulmonary vein. Ablation energy can be transmitted from the electrode to contacted endocardial tissue while the first branch body is located within the pulmonary vein.

Abstract: A cardiac ablation device, including a catheter and an expandable ablation element incorporating one or more balloons at the distal end of the catheter, has a continuous passageway extending through it from the proximal end of the catheter to the distal side of the expandable ablation element. A probe carrying electrodes is introduced through this passageway and deploys, under the influence of its own resilience, to a structure incorporating a loop which is automatically aligned with the axis of the expandable ablation device, so that minimal manipulation is required to place the probe. The probe may have an atraumatic tip with a ball formed at the leading edge. The atraumatic tip prevents any tissue damage such as perforation of heart wall.

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 leads have reduced diameter while providing for optimized mechanical and electrical properties, by reducing the diameters of the conducting cables used within the leads for sensing and delivery of therapeutic electrical stimulation. In an embodiment, conducting filaments within a cable have oval cross-sectional areas. Suitably orienting the oval filaments increases the contact surface between adjacent filaments, broadly distributing the pressure between filaments and reducing fretting fatigue, while the oval cross-sectional area also increases conductivity. In an embodiment, non-conducting coatings around filaments within a cable, or around groups of filaments organized into cable-layers, reduce fretting fatigue. In an embodiment, the cross-sectional area of filaments decreases as the filaments are positioned at increasing radial distances from the center of the cable.

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: 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 steerable multi-linked device. The device includes a first multi-linked mechanism and a second multi-linked mechanism. At least one of the first and second multi-linked mechanisms is steerable and includes a modular link assembly at an end thereof. The modular link assembly includes a base, and a tip removably connected to the base.

Abstract: Medical electrical leads equipped with spacer elements and configured for use during medical procedures such as magnetic resonance imaging (MRI) are disclosed. An illustrative medical electrical lead includes a proximal connector, an insulated lead body including at least one electrode, a helically coiled conductor wire, and a helically coiled spacer element interstitially disposed between adjacent turns of the conductor wire.

Abstract: A trans-septal guide catheter for providing access through the septum separating a first heart chamber from a second heart chamber that includes an elongated guide catheter body extending between guide catheter proximal and distal ends. A distal segment of the guide catheter is adapted to be inserted through the septum to locate the distal segment of the guide catheter within one of the first heart chamber and the second heart chamber. The catheter body encloses a guide catheter lumen adapted to provide access into the one of the first heart chamber and the second heart chamber through a guide catheter lumen proximal end opening and a guide catheter lumen distal end opening. A retention mechanism engages the septum and maintains the distal segment of the guide catheter extending into the one of the first heart chamber and the second heart chamber.

Abstract: A medical electrical lead configured to be coupled to a pulse generator in a cardiac rhythm management system. The lead comprises a proximal terminal connector configured for coupling the lead to the pulse generator, and a plurality of longitudinally arranged lead segments each configured to exhibit one or more predetermined physical characteristics based on the implantation location for the respective segment. The lead segments may be pre-fabricated as separate modules optimized for the operating environment and/or delivery requirements of the respective segments. The pre-fabricated modules are longitudinally arranged and joined to form the lead.

Abstract: A medical electrical lead includes a flexible, insulative body defining a proximal region, an intermediate region, and a distal region. The proximal region is configured to be implanted at a subcutaneous implantation site, and is dimensioned to extend from an implantation location of the pulse generator to a location distal to a cardiovascular system entry site. The intermediate region is configured to extend distally from the proximal region to a location distal to a superior vena cava of a patient's heart, and the distal region is configured to extend distally from the intermediate region within the patient's heart. The lead further includes an armoring layer disposed on the lead body covering at least the proximal region.

Abstract: A lead of an implantable medical device system having an elongated lead body, a sensor coupled to the lead body and extending from a proximal end to a distal end, and a distal lead adaptor having a first arm extending distally from the distal end of the sensor to a first arm end, a second arm extending distally from the distal end of the sensor to a second arm end, and a third arm extending between the first arm end and the second arm end, wherein the first arm, the second arm, and the third arm form an open portion.

Abstract: A medical electrical lead system that includes a catheter extending from a proximal catheter end to a distal catheter end; a lead, insertable within the catheter, including a lead body extending from a proximal lead end to a distal lead end and an active fixation member positioned at the distal lead end; and an advancement tool for advancing the distal lead end outward from the distal catheter end. The advancement tool is adapted to be positioned around the lead body and further adapted to be removably fixedly engaged with the proximal catheter end.

Abstract: A catheter includes an outer jacket, a shaft member, a transition member and a core member. The outer jacket has a first interior passage at a proximal end and a second interior passage at a distal end. The shaft member is arranged within the outer jacket. The transition member is fixedly secured to the shaft member and includes a window. The core member is fixedly secured to the transition member. The window in the transition member allows communication between the first interior passage and the second interior passage.

Abstract: An electrode device for cardiological or neurological electrodiagnosis and/or electrotherapy comprises an elongated electrode body (12), at least one electrode (14, 16) in the vicinity of the distal end (24) of the electrode body (12), and an electrode conductor (44) for the electrical connection of the electrode (14, 16). The electrode conductor (44) has a fibrous structure (52) with anisotropic conductivity so that the specific conductivity of the electrode conductor (44) is significantly higher in its longitudinal direction than in its transverse direction.

Abstract: A cardiac rhythm management system includes a lead assembly for intracardiac mapping, pacing, and drug delivery. The lead assembly includes an implantable endocardial lead having a proximal end for connection to an implantable cardiac rhythm management device and a distal end for disposal in an intracardiac region. The lead includes a pacing-sensing electrode and a drug delivery device, both located at or near the distal end. A lumen is within and extends throughout the lead, with an opening at or near the proximal end and another opening at or near the distal end. The lumen provides for access to the intracardiac region by a steerable stylet and a hollow needle, one at a time. The steerable stylet allows for electrophysiological mapping of the intracardiac region. The hollow needle allows for delivery of chemical, biochemical, and/or biological substance to the intracardiac region.

Abstract: An ultra-wideband assembly is provided. The assembly includes a non-conductive tapered core having a conductive wire wound on an outer surface of the non-conductive tapered core, a low-frequency inductor coupled to the non-conductive tapered core via the distal end of the conductive wire and configured to allow mounting of the non-conductive tapered core at an angle with respect to the circuit board. The low frequency inductor is being disposed on a dielectric board configured to be coupled to the circuit board. The assembly includes an ultra-wideband capacitor coupled to the non-conductive tapered core via the proximate end of the conductive wire, the ultra-wideband capacitor being also coupled to the transmission line on the dielectric board.

Abstract: A transcoronary sinus pacing system comprising a sheath having a lumen, a pacing catheter having a pacing needle, wherein the catheter can be advanced within the lumen and placed in the LV summit, and a right ventricular pacing device. A LV summit pacing device. An early mitral valve closure pacing device configured to operate with a right ventricular apex pacing device. A method for implanting a pacing device at a target coronary sinus tissue location, wherein the target can be the posterior LV summit. A method for achieving early closure of a mitral valve. A method for using visualization devices such as fluoroscopy or ultrasound and/or catheter features such as a radiopaque marker to locate a target location for LV pacing and to avoid piercing an artery or the pericardium when anchoring the LV pacing electrode.

Abstract: A delivery system for implanting a biostimulation device comprising a stylet extending along an axis from knob end to a threaded end configured to engage an internally threaded nut of the biostimulation device and a catheter tube configured to axially contain the stylet. The catheter tube comprises a feature that engages a corresponding feature on the biostimulation device whereby the stylet can be rotated relative to the catheter tube for disengagement of the stylet threaded end from the biostimulation device threaded end.

Abstract: An implantable lead comprises a lead body extending from a lead proximal end portion to a lead distal end portion. The lead body includes one or more longitudinally extending lumens. A conductor is received in, and extends along, a lumen. In varying examples, the implantable lead further comprises a tubular electrode co-axial with, and overlying portions of, the lead body. In one example, a lumen wall is sized and shaped to urge an electrically conductive interposer coupled with the conductor toward an inner surface of the electrode. In another example, a ring member is disposed within a lumen and the conductor is drawn and coupled thereto. In yet another example, an electrically conductive connector couples a first and a second conductor via grooves or threads. In a further example, an axial support member couples a distal end electrode and the lead body. Methods associated with the foregoing are also discussed.

Abstract: Medical carriers that include a low-impedance conductor are provided. The low-impedance conductors are configured to provide electrical conductivity along a length of the medical carrier. An aspect of the low-impedance conductors is the presence of a longitudinally extended region configured as a non-coiled repetitive pattern that imparts fatigue resistance to the longitudinally extended region. Also provided are systems and methods of making the medical carriers, as well as methods of using the medical carriers.

Abstract: A system and method for cardiac mapping and ablation include a multi-electrode catheter introduced percutaneously into a subject's heart and deployable adjacent to various endocardial sites. The electrodes are connectable to a mapping unit, an ablation power unit a pacing unit, all of which are under computer control. Intracardiac electrogram signals emanated from a tachycardia site of origin are detectable by the electrodes. Their arrival times are processed to generate various visual maps to provide real-time guidance for steering the catheter to the tachycardia site of origin. In another aspect, the system also include a physical imaging system which is capable of providing different imaged physical views of the catheter and the heart. These physical views are incorporated into the various visual maps to provide a more physical representation. Once the electrodes are on top of the tachycardia site of origin, electrical energy is supplied by the ablation power unit to effect ablation.

Abstract: Apparatus, system, and method that include a pacing apparatus having a stent electrode through which pulses of electrical current can be delivered. Stent electrodes receive energy for generating the electrical current from a variety of sources. Sources include from one or more induction coils that can form at least a portion of the stent. Sources can also include an implantable pulse generator coupled to a lead through which pulses of the electrical current are supplied to the stent electrodes.

Abstract: In one embodiment, a process, for fabricating a medical lead comprises: providing a splicing tube having a plurality of angularly spaced longitudinal grooves; placing a first plurality of conductors within the plurality of angularly spaced grooves defined on an exterior surface of the splicing tube; placing a second plurality of conductors within the plurality of angularly spaced grooves and adjacent to the first plurality of conductors such that a portion of the distal ends overlap a portion of the proximal ends; positioning conductive filler material adjacent to the overlapped portions of the distal and proximal ends; electrically coupling the proximal ends of the first plurality of electrodes to respective proximal ends of the second plurality of electrodes; molding insulative material about at least the electrode assembly and the splicing tube; and fusing the splicing tube with the insulative material from the molding and the lead body.

Abstract: A distal section of an implantable medical electrical lead body includes a pair of pre-formed arcuate segments between which an approximately straight segment extends. The approximately straight segment includes a first portion extending distally from a first of the pair pre-formed arcuate segments, a second portion extending from the first portion, a third portion extending from the second to a second of the pair pre-formed arcuate segments. An electrode is coupled to the second portion of the approximately straight segment, and the adjacent first portion has a stiffness which is less than that of the first of the pair pre-formed arcuate segments and preferably less than the stiffness of the third portion, so that, when the distal section of the lead body is implanted, for example, within a cardiac vein, the lead buckles to bring the electrode into closer contact with surrounding tissue.

Abstract: A wire form includes a conductor having a distal end and a proximal end. The conductor is coiled and has a predetermined spacing between adjacent coils. The predetermined spacing provides a parasitic capacitance and an inductance. The parasitic capacitance and inductance have a resonance frequency tuned to about an excitation signal's frequency of a magnetic-resonance imaging scanner.

Abstract: A pacing lead for implantation in the pericardial space includes an elongated lead body, a compression fixation element, and at least one electrode on either the lead body or the fixation element. The fixation element defines a resilient structure, and is positioned and dimensioned so that when the lead is disposed in the pericardial space, the resilient fixation element is compressed between the parietal and visceral pericardium, thereby biasing the electrode against the myocardium and providing positional stabilization to the lead. Further positional stability may be provided mechanically with structures enabling the application of adhesive or with fixation screw or tine elements.

Abstract: A medical lead is configured to be implanted into a patient's body and comprises a lead body, and an electrode coupled to the lead body. The electrode comprises a first section configured to contact the patient's body, and a second section electrically coupled to the first section and configured to be capacitively coupled to the patient's body.

Abstract: A drug delivery catheter suited for cardiac procedures. The catheter includes a distal helical coil or other fixation and penetrating element which can be operated from the proximal end of the catheter to engage and penetrate the myocardium. Once delivered to the inside of the heart, the catheter can be used to inject small doses of therapeutic agents to the myocardium. The drug delivery system of the catheter allows for precise control of the dose injected into the heart wall.

Abstract: An electrostimulation system includes an electrostimulation lead which has a connector connected to an electrostimulation device, a conducting wire pair electrically connected to the connector, and a sheathing body insulating the conducting wire pair, and is provided to pass through a vein, an electrostimulation block portion which is provided on the leading end side of the electrostimulation lead, and has an electrode portion electrically connected to the conducting wire pair and fixing hooks urging the electrode portion toward the inner wall of the vein, and a rotary member which has an engagement groove to be detachably engaged with the electrostimulation block portion and rotates the electrostimulation block portion placed in the vein around the center line of the vein through the engagement groove.

Abstract: The present invention is device for delivering an electrode into a lateral vein of the coronary sinus. The device includes a support structure, a stent, a tether coupled to the stent and a removable sheath disposed about the stent. The stent is carried on the support structure and is deployable from a first collapsed configuration to a second expanded configuration for engaging the inner walls of the selected vessel. The sheath is sized to retain the stent in the first collapsed configuration. The electrode is carried on the stent or on a lead threaded over the tether.

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: An implantable medical lead includes a device, such as a physiological sensor, that is coupled to one or more stimulation/sensing sensing conductors within the lead. When the implantable medical lead is coupled to an implantable medical device, the device carried by the lead both receives power from, and communicates with the implantable medical device via the one or more stimulation/sensing sensing conductors. Each of the one or more stimulation/sensing sensing conductors is also coupled to an electrode that is exposed to body tissue.

Abstract: A device for intracavity stimulation of the left atrium and/or ventricle of the heart from the prepectoral region through a less invasive and lower-risk approach is provided that allows the implantation of an intracavity catheter in the left cardiac chambers through a femoral approach atrial transseptal puncture, and the removal of the catheter proximal end by the retrograde venous route.

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: A medical lead having a conductor assembly and a segmented electrode assembly. The segmented electrode assembly includes a conductive segment electrically coupled to a conductor of the conductor assembly. A passageway is positioned between an inner surface and outer surface of the conductive segment. An electrically insulating material extends through the first passageway and into a gap adjacent the conductive segment. A segmented electrode assembly is also provided. The segmented electrode assembly includes a conductive segment having a passageway between an inner surface and outer surface of the conductive segment. An electrically insulating material extends through the passageway and into a gap adjacent the conductive segment.

Abstract: An improved pacemaker lead including a lead body supporting at least one flexible conductor element that provides an electrical signal path between a proximal connector element and a distal electrode. The lead body includes an insulating structure that protects the flexible conductor element(s) wherein the insulating structure is realized from a polymer material comprises an isobutylene block copolymer. The polymer material of the insulating structure has a maximum tensile strength in the range between 20 MPa and 40 MPa (most preferably in a range between 25 MPa and 35 MPa). In the preferred embodiment, the hardness of the polymer material of the insulating structure can be characterized by a Shore hardness in a range between 70A and 80A.

Abstract: The present invention relates generally to multifunctional catheters for performing ablation procedures, and more particularly to ablation catheters utilized in the treatment of atrial fibrillation and other cardiac disorders. The present invention eliminates many of the problems associated with previous ablation catheters by providing an ablation treatment not dependent upon continuous lesions.

Abstract: Apparatus and methods for performing surgery within an organ or vessel are provided. A catheter is provided having a longitudinal axis and an end region carrying an end effector, the end region movable to a series of positions along the longitudinal axis and with an selectable orientation relative to the longitudinal axis. The catheter includes elements for stabilizing the end region of the apparatus within an organ or vessel, and for counteracting reaction forces developed during actuation of the end effector.