EP0538368A4 - Miniature steroid eluting pacing lead electrode - Google Patents
Miniature steroid eluting pacing lead electrodeInfo
- Publication number
- EP0538368A4 EP0538368A4 EP91913321A EP91913321A EP0538368A4 EP 0538368 A4 EP0538368 A4 EP 0538368A4 EP 91913321 A EP91913321 A EP 91913321A EP 91913321 A EP91913321 A EP 91913321A EP 0538368 A4 EP0538368 A4 EP 0538368A4
- Authority
- EP
- European Patent Office
- Prior art keywords
- electrode
- drug
- lead according
- lead
- surface area
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
- A61N1/00—Electrotherapy; Circuits therefor
- A61N1/02—Details
- A61N1/04—Electrodes
- A61N1/05—Electrodes for implantation or insertion into the body, e.g. heart electrode
- A61N1/056—Transvascular endocardial electrode systems
- A61N1/0565—Electrode heads
- A61N1/0568—Electrode heads with drug delivery
Definitions
- This invention relates generally to chronically implanted medical electrode leads and, in particular, to cardiac pacing leads with an electrode structure which minimizes chronic pacing thresholds and drain on the pacing pulse generator power source.
- the safety, efficacy and longevity of an implanted pacemaker system depends (in part) on the performance of its pacing lead(s) , the electronic circuits of the pacemaker pulse generator, the integrity of the pulse generator and the capacity and reliability of the pulse generator power source.
- These inter-related components of the pacemaker system optimally are matched in a fashion that accommodates ever increasing demands on the modes of operation and function of the system in conjunction with an overall reduction in its size, an increase in its longevity and an increased expectation in the reliability of the entire system.
- the technology of cardiac pacing has significantly advanced, with i plantable pacemakers displaying an ever increasing variety of pacing modalities, substantially broadening the indications for pacemaker use.
- Electrodes of many shapes including cylindrical, ball- tip, corkscrew, ring tip and open cage or "bird cage” configurations were pursued with exposed electrode surface areas tending toward 8 mm 2 in the mid 1970's.
- the Medtronic U.S. Patent No. 4,502,492 discloses a low polarization, low threshold electrode design of the early to mid 1980's which was commercialized as the "Target Tip®" pacing leads in numerous models including Models 4011, 4012, 4511 and 4512.
- the tip electrode of the Target Tip® leads was generally hemispherical and provided with circular grooves.
- the electrode was fabricated of platinum, coated over its external surface with a plating of platinum black. The combination of the relatively low electrode surface area and platinum black contributed to state-of-the-art thresholds in that time period.
- a plug of silicone rubber impregnated with the sodium salt of dexamethasone phosphate or the water soluble forms of other glucocorticosteroids was placed in a chamber.
- the silicone rubber plug allowed the release of the steroid through the interstitial gaps in the porous sintered metal electrode to reach the electrode- tissue interface and prevent or reduce inflammation, irritability and subsequent excess fibrosis of the tissue adjacent to the electrode itself.
- the porous steroid eluting electrodes presented a source impedance substantially lower compared to similarly sized solid electrodes and presented significantly lower peak and chronic pacing thresholds than similarly sized solid or porous electrodes.
- steroid eluting electrodes allowed the use of relatively small surface area electrodes of about 5.5 mm 2 (CAPSURE® SP Model 5023, 5523 leads sold by Medtronic, Inc.) to raise the pacing impedance without sacrificing the ability to sense heart activity.
- the smaller electrode size permitted by the '680 patent invention resulted in higher current density during stimulation pulses, provided more efficient stimulation of the heart tissue with lower current drain from the implanted pacemaker power source.
- the localized nature of the drug treatment minimized the systemic assimilation of the drug and avoided undesirable side effects for the patient.
- the electrode- tissue interface impedance It is preferable to decrease lead current drain with more efficient control of the electrode- tissue interface impedance. This can be done by reducing the geometric surface area of the cathode. However, it is commonly believed that small electrodes are inefficient at sensing natural depolarizations of the cardiac tissue. This is not necessarily true, however.
- the amplitude of the intrinsic cardiac depolarization signals (typically the ventricular QRS and/or atrial P-wave complexes) is essentially independent of electrode size, as measured on a high, megohm range input impedance oscilloscope. The problem is that the sense amplifiers of modern pulse generators have comparatively lower input impedance - typically about 35k ⁇ .
- the impedance of the QRS or P-wave signal increases as the electrode surface area decreases.
- a 5 mm 2 polished electrode will produce QRS or P-waves with about 5k ⁇ source impedance.
- the attenuation of the signal in the generator's amplifier is 1/(1 + Zin/Zs) where Zin is the input impedance of the amplifier and Zs is the source impedance of the signal to be sensed.
- the present invention provides a body-implantable lead for the delivery of an electric stimulus to a desired body site, particularly the atrial or ventricular chambers of a patient's heart.
- This lead presents a very high (greater or equal to 800 ohm) pacing impedance with low peak and chronic thresholds, low source impedance and excellent sensing in a size of approximately 1.5 mm 2 exposed geometric (or macroscopic) surface area.
- the lead of the present invention possesses an electrode with an exposed geometric surface area in the range of 0.1 - 4.0 mm 2 , preferably between 0.6 and 3.0 mm 2 , with about 1.0 mm 2 providing optimum performance.
- the lead has a pacing impedance of 1400 ⁇ 260 ohms, a source impedance of about 1650 ⁇ 410 ohms in both chambers of the heart.
- the lead of the present invention constitutes a pacing lead having a spherical, hemispheric or disk shaped exposed distal tip electrode of approximately 1 millimeter in diameter fabricated of platinized porous platinum (or other porous electrode material) , loaded with glucocorticosteroid.
- the electrode is attached to the distal end of a pacing lead of about 1.0 mm or 3 to 4 French in overall diameter.
- Both endocardial and epicardial leads may be fabricated in accordance with the teachings of the present invention.
- DCD electrode technology may be successfully employed with a steroid eluting release device and with apertures in the range of 0.1 to 4.0 mm 2 .
- Figure 1 shows a side plan view of an endocardial, unipolar, ball-tip electrode pacing lead according to the present invention
- Figure 2 shows a cross-sectional view of the ball-tip electrode of the lead shown in Figure 1;
- Figure 3 shows an end plan view of the distal tip of the electrode of the lead shown in Figure 1;
- Figure 4 shows a cross-sectional view of the distal portion of an endocardial, unipolar, DCD electrode pacing lead, according to the present invention;
- Figure 5 shows an end plan view of the distal tip of the DCD electrode of the lead shown in Figure 4;
- Figure 6 shows a cross-sectional view of the distal tip portion of a further endocardial, bipolar, cylindrical tip electrode pacing lead according to the present invention
- Figure 7 shows an end plan view of the distal tip electrode of the lead shown in Figure 6;
- Figure 8 shows a cross-sectional view of the distal tip portion of a further embodiment of the ball-tip electrode according to the present invention.
- Figure 9 shows a cross-sectional view of the distal electrode of a modified DCD electrode according to the present invention.
- Figure 10 shows a plan view of the distal portion of a bipolar epicardial pacing lead according to the present invention
- Figure 11 shows a cross-sectional view of the distal tip portion of the electrode, preferably employed in the epicardial electrode of Figure 10;
- Figure 12 depicts graphically the performance of the exposed electrodes of the present invention with steroid elution against electrodes of the same size and configuration without steroid elution;
- Figure 13 depicts graphically the performance of a DCD electrode of the present invention with steroid elution against a test DCD electrode of the same size and configuration without steroid elution.
- the practice of the present invention contemplates the employment of a steroid or other drug with an electrode possessing a mechanism for allowing the drug to be eluted through and/or around the electrode in order to reach the endocardial or myocardial cells in the vicinity of the tip of the pacing lead in order to reduce, if not eliminate entirely, the acute and chronic inflammation occasioned by the cellular foreign body and physical irritation response to the tip of the lead.
- the electrode is preferably fabricated of body compatible electrically conducting material with or without specific steroid eluting passages but generally with a porous structure either throughout the body of the electrode or at its surface.
- the porosity of the electrode surface or body provides a large surface area for sensing whereas the overall dimension or shape of the exposed electrode defines a comparatively smaller surface area for stimulation.
- the porous structure thus presents a microscopic (or "fractal") large surface area for sensing and a macroscopic or geometrically measured very small surface area for stimulation.
- Electrodes of the present invention may be practiced in the context of electrode structures that have heretofore been referred to as conventional exposed electrodes and the DCD electrode structures of the type shown in the aforementioned Parsonnet patent.
- electrodes of the present invention may be fabricating having characteristics of both the conventional and the DCD electrode structures.
- Dr. Parsonnet in his early work on the DCD electrode, sought to reduce the polarization overvoltage (shown in Figure 2 of his '116 patent) and the resulting postpulse polarization voltages which made and still make it difficult to distinguish the heart's P-waves or R-waves from those postpulse polarization voltages within 5 to 100 milliseconds after the delivery of the stimulus.
- the electrodes may be internalized in,the DCD manner or externalized in the conventional manner.
- the macroscopic surface area through which current is emitted during stimulation is defined by the aperture area presented to the cells in the vicinity of the tip of the pacing lead.
- the large, microscopic surface area is effected, as shown in Figure 4 of the Parsonnet '116 patent, by the conductor coil within the distal portion of the lead body.
- the conductor coil may be rendered textured or porous by one or more of the aforementioned techniques, and steroid is eluted as described further herein below.
- Figure 1 illustrates a plan view of an exposed electrode constructed in accordance with the present invention.
- the lead includes an elongated lead body 10 covered by an insulative sleeve 12.
- Insulative sleeve 12 may be fabricated of any flexible biocompatible and biostable insulator especially silicone rubber or polyurethane.
- terminal assembly 14 is adapted to couple the lead to an implantable pacemaker pulse generator.
- Terminal assembly 14 is provided with sealing rings 16 and a terminal pin 18, all of a type known in the art.
- An anchoring sleeve 20 (shown partially in cross-section) slides over lead body 10 and serves as a point for suturing the lead body to body tissue at the insertion point of the lead into the vein or tissue in a fashion known in the art.
- Anchoring sleeve 20 and terminal assembly 14 may be conveniently fabricated of silicone rubber.
- the lead shown in Figure 1 further includes a stylet guide 11 and stylet assembly 13 coupled to the terminal pin 18 for imparting stiffness to the lead during the insertion and placement of the lead transvenously into either the right ventricle or the right atrium of the heart.
- the stylet guide and stylet assembly are discarded after use and before connection of the terminal pin 18 to a pacemaker pulse generator.
- a tine protector 15 is shown (in cross-section) protecting the tines until the lead is used.
- Tines 26 are employed to passively retain the tip electrode 22 in position against the endocardium as is well known in the pacing art.
- the lead assembly 10 of Figure 1 includes a multifiler conductor coil extending from the terminal pin 18 to the tip electrode 22.
- Figure 1 depicts a unipolar lead and it should be understood that the present invention may be implemented in a bipolar lead design employing a second conductor extending from a second exposed cylindrical terminal surface area*near the proximal end of the lead to an exposed ring electrode spaced > 8 mm from the distal tip electrode 22 as is well known in the art.
- the > 8 mm spacing is necessary because the current sense amplifier bandpass center frequency is about 25-30 Hz. Closer spacings are possible if the sense amplifier bandpass center frequency is shifted to higher values accordingly, and if higher gains are used.
- FIG 2 it shows in cross section a view of the distal lead portion of the preferred embodiment of the electrode of the present invention and its connection to the lead conductor 28.
- the distal electrode 22 is depicted as a porous platinum ball covered with platinum black at the end of a metal pin 23 of platinum extending from the tip electrode 22 to the distal end of the conductor coil 28.
- the conductor coil 28 is attached to the proximal end of the pin by crimping at point 34 of crimping member 36 at the time of manufacture. Silicone adhesive may be used at point 32 to seal the assembly against leakage of blood into the conductor coil.
- the insulative sheath 12 is shown placed over the crimping member as well as the tine assembly 38 which is fit between the distal end of the insulative sheath 12 and the crimping member 54.
- a steroid- silicone rubber compound ring 40 is located proximal from the electrode ball.
- the ball-tip distal electrode 22 is constructed as shown in Figures 2 and 3 to present a circular, hemispheric or spherical exposed macroscopic surface area in the range between 0.1 and 4.0 square mm 2- .
- the ball-tip electrode 22 is fabricated of porous, sintered platinum having a porosity in the range of .5 to 100 microns, employing "splat" powder in the sintering process.
- the porous platinum electrode is electroplated with platinum black and the porosity, together with the platinum black coating is intended to reduce source impedance and polarization.
- the silicone backing sleeve 40 forms a monolithic controlled release device (MCRD) , as it is loaded with an anti-inflammatory agent, e.g., a steroid dexamethasone sodium phosphate.
- MCRD monolithic controlled release device
- the steroid also is deposited within the pores of the porous platinum electrode 22 by application of a solution of 200 mg U.S.P. dexamethasone sodium phosphate dissolved in 5.0 cc isopropanol and 5.0 ⁇ c distilled or deionized water as described in the aforementioned Stokes' patents.
- the MCRD weight and composition as well as the electrode surface area are critical to the electrode's overall performance.
- the small geometric macroscopic electrode size is intended to produce very high pacing impedance.
- the porous surface configuration together with platinum black electroplating and steroid contribute to a microscopically large surface area for low polarization, low source impedance and low thresholds.
- the porous surface also facilitates the retention of steroid and adhesion of the platinum black to the electrode surface.
- FIGs 4 and 5 depict a DCD electrode fabricated in accordance with the teachings of the present invention.
- a platinized coil 50 of platinum wire is crimped to conductor coil 28 using crimp sleeve 52 and crimp core 58.
- Silicone rubber adhesive 54 may be used to provide a seal to assure that blood does not leak into the conductor coil.
- the polymeric insulation tubing 12 extends to the end or just beyond the end of platinized coil 50.
- Three or four symmetrically placed tines 26 are placed close to the distal orifice or aperture 56.
- the aperture 56 of the tubing 12 presents a circular hole of 0.1 to 4.0 mm 2 , about 0.62 mm 2 as shown.
- the lumen of the platinized coil is filled with a solution of 200 mg dexamethasone sodium phosphate in 5 cc water and 5 cc isopropanol. The solvents are allowed to evaporate, leaving a coating of steroid on the coils.
- the steroid loaded MCRD 40 is located at the proximal end of the platinized coil.
- the exposed surface of the platinized coil 50 must be large enough, preferably > 50 mm 2 , to produce low polarization.
- Past DCD electrodes required that the distal lumen be filled with conductive saline prior to insertion into the vein. This is not required with the steroid loaded lead, because the steroid acts as a wetting agent, allowing blood to fill the lumen as the lead is pushed down the vein. In operation, charge transfer from electronic to ionic conduction occurs at the interface of the platinized coil and the blood or fibrotic tissue that eventually fills the lumen. Because this surface is large, polarization losses are low.
- FIGS. 6 and 7 depict an alternative design of the bipolar, endocardial pacing lead of the present invention, and in particular, a modified electrode assembly of the present invention.
- the lead of Figure 6 is constructed in similar fashion to the lead of Figures 1-3 and, to the extent possible, the same numerals will be employed to describe the same or equivalent elements of these two embodiments of the lead.
- Figures 1-3 and Figures 6 and 7 The principal differences between Figures 1-3 and Figures 6 and 7 are that the lead of Figures 6 and 7 is bipolar, possessing a ring electrode 60 spaced from tip electrode 22', the tine elements 26 are constructed somewhat differently and the quadrafiler conductor coil 28 comprises two pair of bifiler, commonly wound, separately insulated conductors, each respectively connected to one of the two electrodes.
- the quadrafiler conductor coil 28 comprises two pair of bifiler, commonly wound, separately insulated conductors, each respectively connected to one of the two electrodes.
- the pin 23 extends through the steroid impregnated ring 40.
- the tip electrode 22' is fabricated of the same materials and treated in the same fashion as the tip electrode 22 of the embodiment of Figures 1-3.
- Figures 6 and 7 thus illustrate a bipolar embodiment of the pacing lead of the present invention.
- Figure 8 discloses a further ball- tip electrode 22" attached to a pin 23 extending back to a similar connection with a coiled wire conductor (not illustrated).
- the tip electrode 22" is virtually fully exposed as is a portion of the distal end of the steroid eluting MCRD 40'.
- the electrode depicted in Figure 8 illustrates an extreme example of the exposed "nanotip” concept of the present invention and may be employed in either endocardial or epi/myocardial lead designs where the tip electrode may penetrate myocardial tissue.
- the exposed surface of the MCRD 40' thus allows for steroid elution in a path in both through and around the spherically shaped electrode 22 " .
- FIG 9 depicts a still further embodiment of the distal portion of the electrode of the present invention.
- the electrode of Figure 9 is a modification of the electrode depicted in Figures 1 to 3 except that, unlike the electrode depicted in Figure 8, the ball-tip electrode 22'" is fully retracted within the distal portion of the tine bearing member 38.
- the inside diameter of the lead tip that is the inside diameter of the tine element 38, is preferably .040 inches which equals a 0.8 mm 2 orifice. Only a hemispheric portion of the surface of the ball electrode 22"' is exposed in this embodiment of the invention.
- FIG. 10 and 11 depict a further embodiment wherein the concept of the present invention is embodied in a bipolar epicardial pacing lead wherein the tip electrode 22"" is mounted on a stem 70 extending from a platform 72 of an epicardial lead body 74 to penetrate into the myocardium.
- the epicardial lead of Figure 10 may be affixed in place by fixation hooks or screws (partially shown at 78) o sutures.
- the specific configuration of the electrode 22"" may take the form of any of the electrodes 22 - 22'" previously described with the exception that the outer surface or tubular member of the extension 70 may need to be stiff enough to allow the tip electrode to penetrate the epicardial membrane.
- the epicardial version of the lead of the present invention may further incorporate a DCD design within body 74 or 70 of the type shown, for example, in the aforementioned Parsonnet '116 patent.
- the tip electrode 22"" and stem 70 are constructed as shown in Figure 11.
- the stem 70 preferably comprises a hollow metal tube 80 having an MCRD 40 located at any point therein between the tip electrode 22"" and the point where the tube is mechanically and electrically connected to the conductor coil (not shown) within housing 74.
- the tip electrode 22"" is attached to the tip of tube 80, and the exterior of the tube 80 is insulated by outer tube 12. The steroid in the MCRD 40 elutes through the porous tip electrode 22"".
- the bipolar mesh electrode 76 shown in Figure 10 may also be soaked with steroid in same fashion as tip electrode 22"".
- the epicardial lead may also be constructed in unipolar fashion substituting a porous fabric for metallic mesh electrode 76 to allow fixation to the epicardium by fibrotic tissue ingrowth.
- Said unipolar leads may also be fixed to the heart by sutures, obviating the need for the fabric mesh.
- Such leads may otherwise possess the features of Medtronic U.S. Patent No. 4,010,758 and designs discussed in a paper by K. Stokes, "Preliminary Studies on a New Steroid Eluting Epicardial Electrode", PACE, Vol. 11.. pp. 1797 - 1803, November, 1988, incorporated herein by reference.
- the electrodes of each of the foregoing embodiments may be fabricated by coating machined electrode blanks or by dipping the end of pin 23 (of Figures 1-3 and 6-10) into a binder, then dipping it into a fluidized bed of platinum splat powder, which adheres to the pin 23 in a generally ball shape, and then sintering the powder.
- the electrode of Figure 11 may be constructed by applying a mixture of the binder and splat powder to the opening of the tube 80 and then sintering it in situ.
- the previously described embodiments of the present invention are illustrative of the construction and features of the very small diameter tip electrodes and pacing leads of the present invention.
- Figure 12 depicts the results of a paired study in canines of the ventricular "nanotip" leads with and without steroid over an 8 week study period.
- the stimulation thresholds show a marked rise for the leads without steroid as compared to those leads with steroid.
- the very small “nanotip", exposed and DCD electrodes of the present invention satisfy the aforementioned desirable characteristics of a pacing lead, that has low stimulation thresholds very high pacing impedance (800 - 2500 ohms) relatively low polarization, good to excellent sensing, and adequately low source impedance.
- the high pacing impedance prolongs the longevity of pacing pulse generators and allows for the miniaturization of their components.
- the low thresholds allow large safety factors at low applied voltages, which also contribute to increased battery longevity.
- the embodiments of the present invention have been described in particular application to cardiac pacing, it will be understood that the invention may be practiced in other electrode technologies where the aforementioned characteristics are desirable, including neurological and muscle stimulation applications.
- the miniaturization of the electrodes afforded by the present invention may advantageously allow the clustering of two or more electrode structures at the tip of a stimulation/sensing lead or probe.
- the present invention may advantageously be implemented in tip electrode configurations of the type illustrated in Sleutz et al U.S. Patent No. 4,662,382 in order to provide practical closely spaced bipolar stimulation and sensing.
Abstract
Description
Claims
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US53910290A | 1990-06-15 | 1990-06-15 | |
US539102 | 1990-06-15 |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0538368A1 EP0538368A1 (en) | 1993-04-28 |
EP0538368A4 true EP0538368A4 (en) | 1995-04-19 |
Family
ID=24149781
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP91913321A Withdrawn EP0538368A4 (en) | 1990-06-15 | 1991-06-11 | Miniature steroid eluting pacing lead electrode |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP0538368A4 (en) |
JP (1) | JP3300954B2 (en) |
AU (1) | AU652377B2 (en) |
CA (1) | CA2085369A1 (en) |
WO (1) | WO1991019533A1 (en) |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5385579A (en) * | 1993-03-30 | 1995-01-31 | Siemens Pacesetter, Inc. | Myocardial body implantable lead |
FR2751232B1 (en) * | 1996-07-19 | 1998-09-25 | Ela Medical Sa | PROBE FOR IMPLANTED MEDICAL DEVICE, PARTICULARLY FOR HEART STIMULATOR |
US6363286B1 (en) | 1999-09-24 | 2002-03-26 | Cardiac Pacemakers, Inc. | High impedance electrode assembly |
US6671562B2 (en) | 2001-11-09 | 2003-12-30 | Oscor Inc. | High impedance drug eluting cardiac lead |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3476116A (en) * | 1967-11-09 | 1969-11-04 | Victor Parsonnet | Nonpolarizing electrode for physiological stimulation |
US4280514A (en) * | 1975-05-09 | 1981-07-28 | Macgregor David C | Endocardial pacemaker electrode |
Family Cites Families (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4934381A (en) * | 1975-05-09 | 1990-06-19 | Macgregor David C | Porous carbon pacemaker electrode |
US4506680A (en) * | 1983-03-17 | 1985-03-26 | Medtronic, Inc. | Drug dispensing body implantable lead |
US4502492A (en) * | 1983-04-28 | 1985-03-05 | Medtronic, Inc. | Low-polarization low-threshold electrode |
US4953564A (en) * | 1989-08-23 | 1990-09-04 | Medtronic, Inc. | Screw-in drug eluting lead |
-
1991
- 1991-06-11 EP EP91913321A patent/EP0538368A4/en not_active Withdrawn
- 1991-06-11 CA CA 2085369 patent/CA2085369A1/en not_active Abandoned
- 1991-06-11 AU AU82248/91A patent/AU652377B2/en not_active Ceased
- 1991-06-11 JP JP51241591A patent/JP3300954B2/en not_active Expired - Lifetime
- 1991-06-11 WO PCT/US1991/004122 patent/WO1991019533A1/en not_active Application Discontinuation
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3476116A (en) * | 1967-11-09 | 1969-11-04 | Victor Parsonnet | Nonpolarizing electrode for physiological stimulation |
US4280514A (en) * | 1975-05-09 | 1981-07-28 | Macgregor David C | Endocardial pacemaker electrode |
Non-Patent Citations (2)
Title |
---|
See also references of WO9119533A1 * |
STOKES: "implantable pacing lead technology", IEEE ENGINEERING IN MEDICINE AND BIOLOGY MAGAZINE, vol. 9, no. 2, 1 June 1990 (1990-06-01), NEW YORK US, pages 43 - 49, XP000173571, DOI: doi:10.1109/51.57868 * |
Also Published As
Publication number | Publication date |
---|---|
WO1991019533A1 (en) | 1991-12-26 |
EP0538368A1 (en) | 1993-04-28 |
JPH06501169A (en) | 1994-02-10 |
JP3300954B2 (en) | 2002-07-08 |
AU8224891A (en) | 1992-01-07 |
CA2085369A1 (en) | 1991-12-16 |
AU652377B2 (en) | 1994-08-25 |
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