Source: http://www.google.com/patents/US20020055674?dq=%22edwin+asa+markham%22
Timestamp: 2017-11-21 12:18:48
Document Index: 524277474

Matched Legal Cases: ['art.\n51', 'art.\n54', 'art;\n56', 'art.\n62', 'application No. 60', 'application No. 60', 'art 120', 'application No. 60']

Patent US20020055674 - Mapping catheter - Google Patents
An elongate probe apparatus (20) for insertion into the body of a subject, comprising: a structure (24) having a substantially rigid configuration, a plurality of physiological sensors (26, 28, 30), which generate signals responsive to a physiological activity, said sensors (24, 28, 30) having substantially...http://www.google.com/patents/US20020055674?utm_source=gb-gplus-sharePatent US20020055674 - Mapping catheter
Publication number US20020055674 A1
Also published as CA2242353A1, CA2242353C, DE69738547D1, DE69738547T2, EP0888082A1, EP0888082B1, EP1382293A2, EP1382293A3, EP1382293B1, EP1428472A2, EP1428472A3, US6574492, US6600948, WO1997024983A2
Publication number 09109802, 109802, US 2002/0055674 A1, US 2002/055674 A1, US 20020055674 A1, US 20020055674A1, US 2002055674 A1, US 2002055674A1, US-A1-20020055674, US-A1-2002055674, US2002/0055674A1, US2002/055674A1, US20020055674 A1, US20020055674A1, US2002055674 A1, US2002055674A1
Inventors Shlomo Ben-Haim, Ilan Greenberg, Maier Fenster
Original Assignee Shlomo Ben-Haim, Ilan Greenberg, Maier Fenster
Referenced by (36), Classifications (87), Legal Events (4)
US 20020055674 A1
An elongate probe apparatus (20) for insertion into the body of a subject, comprising: a structure (24) having a substantially rigid configuration, a plurality of physiological sensors (26, 28, 30), which generate signals responsive to a physiological activity, said sensors (24, 28, 30) having substantially fixed positions on said structure (24) in said configuration; and one or more devices that generate position signals indicative of the positions of the physiological sensors on said structure in said configuration.
1. An elongate probe apparatus for insertion into the body of a subject, comprising:
a structure having a substantially rigid configuration;
a plurality of physiological sensors, which generate signals responsive to a physiological activity, said sensors having substantially fixed positions on said structure in said configuration; and
one or more devices that generate position signals indicative of the positions of the physiological sensors on said structure in said configuration.
2. Apparatus in accordance with claim 1, wherein the elongate probe comprises a distal end, which is inserted into the body of the subject, and
wherein said structure in said configuration has a known shape and orientation relative to the distal end of the probe.
3. Apparatus in accordance with claim 1 or 2, wherein said structure comprises resilient material.
4. Apparatus in accordance with claim 3, wherein the resilient material is superelastic.
5. Apparatus in accordance with any of the preceding claims, wherein the structure has the shape of a ring in said substantially rigid configuration.
6. Apparatus in accordance with claim 5, wherein the sensors are mutually spaced around the circumference of the ring.
7. Apparatus in accordance with claim 5 or 6, wherein the structure comprises a flat strip, formed into a ring shape.
8. Apparatus in accordance with claim 5 or 6, wherein said structure comprises a hollow tube.
the hollow tube formed of flexible material; and
the structure further comprises a curved stylette, insertable into the center of the hollow tube so as to cause the hollow tube to assume a curved shape.
10. Apparatus in accordance with any of claims 1-4, wherein said structure has a polygonal shape in said substantially rigid configuration.
11. Apparatus in accordance with claim 10, wherein said polygonal shape is triangular.
12. Apparatus in accordance with claim 10 or 11, wherein the sensors are adjacent to the vertices of said structure in said substantially rigid configuration.
13. Apparatus in accordance with any of claims 1-4, wherein said structure comprises a multiplicity of arms, and
wherein when the structure is in said substantially rigid configuration, said arms spread radially outward relative to an axis parallel to the long dimension of said elongate probe.
14. Apparatus in accordance with claim 13, wherein the arms comprise substantially rigid segments, which are coupled by resilient joints.
15. Apparatus in accordance with claim 14, wherein flexure of the joints causes the arms to spread radially outward in said substantially rigid configuration.
said elongate probe further comprises mutually spaced radial openings in an outer surface thereof, and
said arms protrude from the probe through said openings.
17. Apparatus in accordance with any of claims 1-6, wherein said structure further comprises an inflatable element, and
wherein inflation of the inflatable element causes the structure to assume said substantially rigid configuration.
18. Apparatus in accordance with claim 17, wherein the inflatable element is a balloon.
19. Apparatus in accordance with claim 17 or 18, wherein the structure further comprises flexible, non-extensible wires.
20. Apparatus in accordance with any of the preceding claims, wherein when the structure is in said substantially rigid configuration, the positions of said sensors on said structure define a plane, with a first axis perpendicular to this plane; and
the elongate probe defines a second axis parallel to its long dimension.
21. Apparatus in accordance with claim 20, wherein the first axis is substantially parallel to the second axis.
22. Apparatus in accordance with claim 20, wherein the first axis is substantially perpendicular to the second axis.
23. Apparatus in accordance with any of the preceding claims, wherein said structure has a second configuration, in which said structure is relatively narrow and elongated.
24. Apparatus in accordance with claim 23, wherein said structure in said narrow, elongated configuration has a long axis that is substantially parallel to an axis defined by the long dimension of the elongate probe.
25. Apparatus in accordance with any of claims 5-7, wherein the elongate probe comprises an external sheath, defining a central cavity, and wherein said ring is constructed so as to be withdrawn into said central cavity and compressed thereby into a narrow, elongated configuration.
26. Apparatus in accordance with claim 8 or 9, and further comprising a straight stylette, insertable into the center of the hollow tube, so as to cause the hollow tube to assume a straight shape.
27. Apparatus in accordance with any of claims 9-11, wherein the structure includes a distal tip, and the elongate probe includes a socket in a side thereof, and
wherein the distal tip of the structure engages the socket when the structure assumes said substantially rigid, ring-shaped configuration.
28. Apparatus in accordance with claim 26, wherein the distal tip of the structure comprises a first electrical contact, and the socket in a side of the catheter comprises a second electrical contact, and
mean for measuring contact between the first and second electrical contacts so as to verify that the distal tip has engaged the socket.
29. Apparatus in accordance with claim 14 or 15, and wherein straightening said joints causes said segments to maintain a substantially parallel alignment with an axis parallel to the long dimension of said elongate probe.
30. Apparatus in accordance with claim 16, said elongate probe further comprises one or more lumens, and
wherein said structure has a second configuration wherein said arms are held inside the one or more lumens.
31. Apparatus in accordance with any of the preceding claims, wherein at least one of the one or more position signal generating devices is fixed in a known relation to the position of said structure in said substantially rigid configuration.
32. Apparatus in accordance with claim 31, wherein at least one of the one or more position signal generating devices is fixed to the distal end of the elongate probe.
33. Apparatus in accordance with claim 32, wherein said position signal generating device, fixed to the distal end of the elongate probe, comprises one or more coils, and
wherein said coils generate position indication signals in response to an externally applied magnetic field.
34. Apparatus in accordance with claim 33, and wherein said one or more coils comprise three non-concentric coils.
35. Apparatus in accordance with any of claims 31-34, wherein at least one of the one or more position signal generating devices generates six-dimensional position and orientation information.
36. Apparatus in accordance with any of claims 31-35, wherein the one or more position signal generating devices comprise at least two devices for generating three-dimensional location information, wherein the devices are placed in a mutually spaced relation.
37. Apparatus in accordance with any of claims 31-36, wherein one of the one or more position signal generating devices is substantially rigidly coupled with each of the sensors.
38. Apparatus in accordance with any of claims 31-37, wherein the one or more position signal generating devices comprise at least one device that generates three-dimensional location signals, and at least one device that generates angular orientation signals.
39. Apparatus in accordance with claim 38, wherein at least one device that generates angular orientation signals is a rotation measuring device.
40. Apparatus in accordance with claim 39, and including a rotation measuring device that generates information regarding the rotation of the catheter about an axis defined by the catheter's long dimension.
41. Apparatus in accordance with claim 39 or 40, and including a rotation measuring device that generates information regarding deflection of the distal end of the catheter.
42. Apparatus in accordance with any of the preceding claims, wherein the sensors are adapted to detect electrical impulses in the endocardium.
43. Apparatus in accordance with claim 42, wherein the sensors are electrodes adapted to be placed in contact with the endocardium.
44. Apparatus in accordance with any of claims 1-41, wherein the sensors are adapted to detect electrical signals in the brain.
45. Apparatus in accordance with any of claims 1-41, wherein the sensors are ionic sensors.
46. Apparatus for measuring physiological activity comprising elongate probe apparatus in accordance with any of the preceding claims, and further comprising signal processing circuitry, which receives and processes position signals from said probe, so as to determine the positions of said physiological sensors.
47. Apparatus in accordance with claim 46, and wherein said signal processing circuitry is further adapted to measure a vector relating to said physiological activity.
48. Apparatus for measuring physiological activity comprising elongate probe apparatus in accordance with any of claims 1-45, and further comprising signal processing circuitry, which is adapted to receive and processes physiological signals from said probe, so as to measure a vector relating to said physiological activity.
49. Apparatus for measuring physiological activity, comprising:
an elongate probe for insertion into the body of a subject, said probe comprising a plurality of physiological sensors, wherein said sensors generate signals responsive to said physiological activity; and
signal processing circuitry, which receives and processes physiological signals from said probe, so as to measure a vector relating to said physiological activity.
50. Apparatus for measuring physiological activity comprising elongate probe apparatus in accordance with claim 41 or 42, and further comprising signal processing circuitry, which computes an electrical activation vector in the heart.
51. Apparatus in accordance with any of claims 41, 42 and 50, and further comprising a second elongate probe, having a distal end, which is inserted into a human body; and
a device that generates position signals indicative of the three-dimensional location of the distal end of said second probe.
52. Apparatus in accordance with claim 51, wherein the second elongate probe is adapted to be substantially fixed in a chamber of the heart, and
wherein the position signals generated by the device indicative of the location of the distal end of said second probe define a reference frame relative to which the position and orientation of said structure are determined.
53. Apparatus in accordance with claim 51 or 52, wherein said second probe is adapted to be substantially fixed adjacent to the apex of the heart.
54. A method for generating information for the mapping of electrical activity in the endocardium of a heart, comprising:
inserting a catheter, having a distal end and a structure having a substantially rigid configuration connected thereto, to which structure a plurality of sensors are fixed in known positions, into a chamber of the heart, so as to bring the sensors into contact with a locus in the endocardium;
55. A method for generating information for the mapping of electrical activity in the endocardium of a heart, comprising:
inserting a first catheter, having a distal end and a structure having a substantially rigid configuration connected thereto, to which structure a plurality of sensors are fixed in known positions, into a chamber of the heart, so as to bring the sensors into contact with a locus in the endocardium;
inserting a second catheter, having a distal end and a device that generates three-dimensional location information connected thereto, into a chamber of the heart, so as to fix the distal end of the second catheter in a known, predetermined position in the chamber of the heart;
56. A method in accordance with claim 54 or 55, wherein said structure is inserted into a chamber of the heart by passing the structure through a blood vessel, and
wherein during said insertion, the structure assumes a second configuration, which is narrow and elongated so as to pass easily through the blood vessel.
57. A method in accordance with any of claims 54-56, wherein the one or more devices for generating position information measure the position and orientation of the structure.
58. A method in accordance with any of claims 54-57, wherein the electrical signals and the position information are used to determine an activation vector at the locus.
59. A method in accordance with claim 58, wherein the vector is determined by measuring activation times of the electrical signals.
60. A method in accordance with claim 58 or claim 59, wherein the sensors are coupled together as bipolar electrodes, and the vector is determined by measuring amplitudes of electrical signals received from the bipolar electrodes.
61. A method in accordance with any of claims 58-60, and further comprising mapping the activation vector by receiving electrical signals from the endocardium and determining the respective positions of the sensors at multiple loci in the heart.
62. A method in accordance with any of claims 54-61, wherein the location of a defect in the heart's electrical conduction is determined by measuring the direction of propagation of electrical impulses in the heart repeatedly at multiple locations.
63. A catheter insertable into a body vessel comprising:
at least one resilient member extending from a distal end of said tubular body portion, said at least one resilient member being adapted to bend over the outside of the distal end of the tubular portion and to extend distally from the distal end of the tubular portion.
64. A catheter according to claim 63 wherein the at least one resilient member is adapted to bend over the outside of the distal end of the tubular portion during distal motion of the catheter in a vessel and is adapted to extend distally from the distal end of the tubular portion during proximal motion of the catheter in the vessel.
65. A catheter according to claim 63 or claim 64 wherein the at least one resilient member has a rest position at which it does not extend axially from the tubular section.
66. A catheter according to any of claims 63-66 wherein the at least one resilient member comprises a plurality of resilient members attached to the distal end of the tubular section.
67. A catheter according to claim 66 wherein said plurality of resilient members are substantially symmetrically arranged about a longitudinal axis of said catheter.
68. A catheter according to any of claims 64-67 wherein the at least one resilient member is comprised in a cap attached to the distal end of the tubular member.
69. A catheter according to claim 68 wherein the cap comprises a sleeve extending from a proximal end of said resilient member and attachable to said distal end of said tubular body portion, wherein at least one radial dimple is formed at a juncture between said sleeve and said resilient member.
70. A catheter according to any of claims 64-69 wherein the at least one resilient member is constructed of an elastomeric material.
71. A catheter according to any of claims 64-70 and comprising at least one bump protruding from said at least one resilient member.
72. A catheter according to claim 71 and comprising at least one sensor fixed to said bump.
73. A catheter according to any of claims 64-71 and comprising at least one sensor fixed to said at least one resilient member.
74. A catheter according to claim 72 or claim 73 wherein said at least one sensor is selected from the group consisting of a position sensor, a six degree of freedom position and orientation sensor, a monopolar electrode, a bipolar electrode, a strain gauge and a physiological activity sensor.
75. A method for sensing a physiological activity of tissue inside a body organ, comprising:
76. A method according to claim 19 wherein said sensors sense a physiological activity substantially simultaneously.
77. A method according to claim 76 wherein said physiological activity is selected from the group consisting of movement of said tissue, contraction time of a heart muscle, an activation signal of a heart muscle, and velocity of fluid flow.
78. A method for determining a velocity relating to physiological activity at a location in a tissue, comprising:
79. A method in accordance with claim 78, wherein each of the two non-parallel axes is defined by a respective pair of the known positions.
80. A method in accordance with claim 79, wherein each of the velocity component vectors has a magnitude determined by arithmetically dividing the distance separating the pair of known positions that define the respective axis of the velocity component vector, by the difference of the characteristic times between the known positions.
81. A method in accordance with any of claims 78-80, and comprising finding one of the plurality of positions that has a characteristic time not substantially equal to the characteristic times of the other positions.
82. A method in accordance with claim 81, and comprising taking the position whose characteristic time is not substantially equal to the characteristic times of the other positions as a reference point for computing the velocity component vectors.
83. A method in accordance with claim 82, wherein both of the non-parallel axes are taken to pass through the reference point.
84. A method in accordance with any of claims 78-83, and comprising identifying the location as a possible site of pathology when all of the plurality of positions are found to have a substantially equal characteristic times.
85. A method in accordance with any of claims 78-84, and comprising determining the coordinates of the location relative to an external frame of reference.
86. A method in accordance with any of claims 78-85, wherein the signals are electrical signals, which are received by a plurality of electrodes at a plurality of known, respective positions.
87. A method in accordance with claim 86, and comprising fixing the electrodes at the distal end of a catheter, and inserting the catheter into a chamber of the heart of a subject, and wherein the velocity is a velocity of local electrical activation in the endocardium.
88. A method in accordance with claim 87, and comprising bringing the electrodes into contact with the endocardium, adjacent to the location at which the velocity is to be determined.
89. A method in accordance with claim 86, wherein the velocity is a measure of ionic current.
90. A method in accordance with claim 86, and comprising bringing the electrodes into proximity with a location in the brain, and wherein the velocity is a velocity of local electrical activation in the brain of a subject.
91. A method of mapping the velocity of local electrical activation in a plurality of locations in the endocardium, comprising determining the velocity at a plurality of known locations in the tissue, in accordance with any of claims 78-90, and recording the velocity thus determined as a function of the respective known locations.
Because of these drawbacks of single-electrode mapping, a number of inventors have taught the use of multiple electrodes to measure electrical potentials simultaneously at different locations in the endocardium, thereby allowing activation time to be mapped more rapidly and conveniently, as described, for example, in PCT patent publication WO 95105773, whose disclosure is incorporated herein by reference. In this case, the positions of all the electrode sensors must be determined at the time of measurement, typically by means of fluoroscopic or ultrasonic imaging. These methods of position determination, however, are complicated, inconvenient and relatively inaccurate, therefore limiting the accuracy of mapping.
Detecting the position in space of a single electrophysiology mapping electrode is described, inter alia, in PCT patent application number PCT/US95/01103, filed Jan. 24, 1995, U.S. provisional application No. 60/009,769, filed Jan. 11, 1996, U.S. patent application Ser. No. 08/1595,365, filed Feb. 1, 1996, both titled “Cardiac Electromechanics”, and U.S. Pat. No. 5,391,199, issued Feb. 21,1995, the disclosures of all of which are incorporated herein by reference.
[0126]FIG. 1 is a generalized, conceptual schematic illustration of a catheter, in accordance with a preferred embodiment of the present invention;
[0127]FIG. 2 is a schematic illustration of a system incorporating the catheter of FIG. 1, in accordance with a preferred embodiment of the present invention;
[0128]FIG. 3 is a schematic representation of a portion of the catheter of FIG. 1, showing electrical signals as received at different sites thereon, useful in understanding the operation of the invention;
[0129]FIG. 4A is a schematic, perspective representation of a system including a catheter, to which electrodes are fixed, according to a preferred embodiment of the present invention;
[0131]FIG. 5 is a flow chart illustrating schematically a method of determining the magnitude and direction of a vector, in accordance with a preferred embodiment of the present invention, as shown in FIGS. 4B-D;
[0132]FIG. 6A is a cross-sectional view of a catheter in a configuration suitable for insertion into a patient's body and removal therefrom, in accordance with one preferred embodiment of the invention;
[0133]FIG. 6B is a cross-sectional view of the catheter of FIG. 6A in an alternative configuration suitable for performing electrophysiological measurements inside the body;
[0134]FIG. 7 is a three-dimensional graphic representation of the catheter shown in FIG. 6B;
[0135]FIG. 8A is a cross-sectional view of a catheter in a configuration suitable for insertion into a patient's body and removal therefrom, in accordance with another preferred embodiment of the invention;
[0136]FIG. 8B is a cross-sectional view of the catheter of FIG. 8A in an alternative configuration suitable for performing electrophysiological measurements inside the body;
[0137]FIG. 8C is a perspective view of the catheter of FIG. 8A in a different alternative configuration suitable for performing electrophysiological measurements inside the body;
[0138]FIG. 9 is a cross-sectional view of a catheter in accordance with an alternative preferred embodiment of the invention, in a configuration suitable for performing electrophysiological measurements inside the body;
[0139]FIG. 10A is a perspective view of a catheter in accordance with still another preferred embodiment of the present invention, shown in transition from a closed configuration to an open configuration;
[0140]FIG. 10B is a perspective view of the catheter of FIG. 10A, shown in a closed configuration suitable for insertion into and removal from a human body;
[0141]FIG. 10C is a perspective view of the catheter of FIG. 10A, shown in an open configuration suitable for performing electrophysiological measurements inside the body;
[0142]FIG. 11A is a schematic, cross-sectional view of a catheter in accordance with yet another preferred embodiment of the present invention, shown in a closed configuration suitable for insertion into and removal from a human body;
[0143]FIG. 11B is a perspective view of the catheter of FIG. 11A, shown in an open configuration suitable for performing electrophysiological measurements inside the body;
[0144]FIG. 12A is a schematic view of a catheter in accordance with still another preferred embodiment of the present invention, shown in a collapsed configuration suitable for insertion into and removal from a human body;
[0145]FIG. 12B is a schematic illustration of the catheter of FIG. 12A, shown in an expanded configuration suitable for performing electrophysiological measurements inside the body;
[0146]FIG. 13A is a schematic view of a catheter in accordance with another preferred embodiment of the present invention, shown in a collapsed configuration suitable for insertion into and removal from a human body;
[0147]FIG. 13B is a schematic illustration of the catheter of FIG. 13A, shown in an expanded configuration suitable for performing electrophysiological measurements inside the body;
[0148]FIG. 14A is a simplified pictorial illustration of a catheter and a covering attached thereto, constructed and operative in accordance with a preferred embodiment of the present invention;
[0149]FIG. 14B is a front end view of the catheter of FIG. 14A
[0150]FIG. 15 is a simplified pictorial illustration depicting insertion of the catheter of FIG. 14A into a body vessel;
[0151]FIG. 16 is a simplified pictorial illustration of using the catheter of FIG. 14A to sense a physiological activity of tissue inside a body organ, in accordance with a preferred embodiment of the present invention;
[0152]FIG. 17 is a schematic illustration of a catheter with a control handle, in accordance with a preferred embodiment of the present invention; and
[0153]FIGS. 18A and 18B illustrate a steering mechanism in accordance with a preferred embodiment of the present invention.
The relative time of arrival of the signal peak at each of the electrodes can thus be used to determine the magnitude and direction of {right arrow over (V)} relative to ring 24. Referring to FIG. 3, we note by way of example that the time difference between the signal peaks at electrodes 26 and 28, τ2=t2−t1, is roughly twice the time difference for electrodes 26 and 30, τ3=t3-t1. This temporal measurement indicates that the electrical activation wave front passing electrode 26 takes twice as long to reach electrode 30 as it does to reach electrode 28, and thus that vector {right arrow over (V)} points from the position of electrode 26 toward that of electrode 30. If the ratio τ2/T3 were relatively smaller, {right arrow over (V)} would be found to be rotated clockwise relative to the direction shown in FIG. 3, while if the ratio were larger, {right arrow over (V)} would be rotated counterclockwise.
For example, pairs of electrodes, such as electrodes 26 and 28, may be coupled together so as to act as bipolar electrodes. In this case, the signal processing electronics will detect the electrical potential difference between electrodes 26 and 28, for example, corresponding substantially to the local electrical activity between the electrodes. If, in this example, the direction of the local electrical activation vector has a large component directed from electrode 26 toward electrode 28, the bipolar signal measured between these electrodes will have relatively large amplitude. If the vector has a large component directed from electrode 28 toward electrode 26, the bipolar signal will also have relatively large amplitude, although of opposite sign to that of the preceding case. If, however, the vector points in a direction substantially perpendicular to an axis passing through electrodes 26 and 28, the amplitude of the bipolar signal will be relatively small or zero.
{right arrow over (V)} is now computed, based on the following procedure, illustrated by FIG. 4C. Point “p” is located on the line “ab” connecting points “a” and “b”, such that velocity vector is perpendicular thereto. Using vector arithmetic:
{overscore (Ab)}=a−b (1)
{overscore (Cb)}=c−b (2) cos   α = A _   b · C _   b  A _   b  ·  C _   b  ( 3 ) p - b =  C _   b  · cos   α  A _   b  A _   b  ( 4 ) p = b +  C _   b  · cos   α  A _   b  A _   b  ( 5 )
{overscore (Cp)}=c−p (6) V _ = C _   p τ max - τ min ( 7 )
A method, in accordance with preferred embodiments of the present invention, for mapping a vector velocity of electrical activation {right arrow over (V)}, as a function of time, in the endocardium, uses catheter 20 or similar apparatus: First, the catheter is brought into contact with a location in the endocardium, and vectors {right arrow over (A)}, {right arrow over (B)} and {right arrow over (C)}, are determined, corresponding to the respective positions of electrodes 226, 228 and 230. It will be appreciated that in accordance with the preferred embodiment of the present invention described with reference to FIG. 4A, it is sufficient to determine the position and orientation of distal end of catheter 220, in order to determine {right arrow over (A)}, {right arrow over (B)} and {right arrow over (C)}.
{right arrow over (V)} is now computed, based on the following procedure. Velocity component vectors {overscore (P)}B and {overscore (P)}C are determined based on the measured electrode positions and local electrical activation times: P _ B = B _ - A _ τ B - τ A ( 8 ) P _ C = C _ - A _ τ C - τ A ( 9 )
{overscore (P)} CB ={overscore (P)} B −{overscore (P)} C (10) P ^ CB = P _ CB  P _ CB  ( 11 )
{overscore (V)}={overscore (P)} B−({circumflex over (P)}CB ·{circumflex over (P)} B){circumflex over (P)} CB (12)
It will be appreciated from equation (10) that if τB=τC, then {circumflex over (P)}CB will be normal to an axis passing through points B and C, which correspond to the positions of electrodes 224 and 226 respectively.
In another preferred embodiment of the present invention, shown in FIGS. 11A and 11B, electrodes 26, 28 and 30 are fixed adjacent to and aligned with the distal ends of substantially rigid arms 80, 82 and 84 respectively. As shown in FIG. 11A, during insertion of catheter 20 into the heart or removal therefrom, the arms are contained inside respective lumens 85, 86 and 87 of the catheter, wherein the distal ends of the arms are adjacent to small radial openings 88, 90 and 92, respectively, in sheath 22 of the catheter. A device 32 for generating coordinate information is adjacent to the distal end of the catheter.
One solution to these problems is to provide the catheter with a soft smooth tip. In a preferred embodiments of the invention, the structure to which electrodes are fixed at the distal end of the catheter is coupled to an inflatable element, such as a balloon, After the catheter has been inserted into the heart, the inflatable element is inflated and causes the structure to assume a predetermined, known shape and orientation relative to the distal end of the catheter.
[0234]FIG. 14B shows a front view of catheter 310. The lack of any sharp angles in this embodiment should be appreciated. In a preferred embodiment of the invention, at least one opening 333 to a lumen is formed in each lobe 322. Such a lumen may be used to provide an extendible barb for attaching the lobe to the myocardium. Alternatively, such a lumen may be connected to a vacuum pump to provide anchoring via suction. Further alternatively, such a lumen may be used to provide irrigation to the region of sensor 332. Preferably, anchoring means such as barbs and suction are applied only after sensor 332 is in good contact with the myocardium. The quality of contact is preferably determined using electrical activity signals and/or impedance signals from sensors 332.
[0249]FIGS. 18A and 18B illustrate a catheter steering mechanism for a catheter 432 in accordance with a preferred embodiment of the invention. The mechanism, indicated by the dotted line, includes a stiffener 420 attached to a flat, flexible, elastic, member 416. The distal portion of member 416 is coiled into a spiral, through which a loop 430 is threaded. Loop 430 is formed at a distal end of a pull wire 412, which when pulled, cause flexible member 416 to bend, thereby bending the tip of catheter 432. Since member 416 is flat, it has a preferred bending plane perpendicular to its face, along arrow 434. The proximal end of pull wire 412 is preferably wound on a shaft 414, such that when shaft 414 is rotated, pull wire 412 is either tensed or relaxed, based on the turn direction. Pull wire 412 is preferably formed of Kevlar.
In the preferred embodiment shown in FIG. 2, field generator coils 27 fixed to operating table 29 define an external reference frame, relative to which the position of position information generating device 32 is determined. In other preferred embodiments of the present invention, however, an external reference frame is defined and fixed relative to the heart muscle, as described, for example, by U.S. Pat. No. 5,391,199 and U.S. provisional patent application No. 60/009,769, filed Jan. 11, 1996, which are assigned to the assignee of the present application and whose disclosures are incorporated herein by reference. These disclosures teach apparatus and methods for mapping the interior of the heart using two catheters, each of which includes a device that generates coordinate information. One of the catheters is positioned in a predetermined, substantially fixed location in the heart, preferably at the apex of the heart, and serves as a reference catheter. By fixing the reference frame to the heart, errors in mapping of the heart that may arise due to the motion of the heart and chest are reduced.
Accordingly, in a preferred embodiment of the present invention, two catheters are inserted into heart 120. The first catheter 20 comprises ring 24 with electrodes 26, 28, 30 and coordinate information generating device 32 at its distal end, as described above. A second catheter, also comprises a coordinate information generating device adjacent to its distal end, and is positioned in a predetermined, substantially fixed location in a chamber of the heart, preferably at the apex of the heart. This second catheter thus defines a reference frame that is substantially fixed with respect to the heart, relative to-which the position of the first catheter is determined.
This preferred embodiment has the advantage that errors in mapping the propagation of electrical impulses in the heart that may arise due to motion of the heart and chest are avoided, and furthermore that electrical propagation vectors, such as activation vector {right arrow over (V)}, may be mapped relative to an accurate map of the interior of the heart generated in accordance with U.S. Pat. No. 5,391,199 and U.S. provisional patent application No. 60/009,769, filed Jan. 11, 1996. The frame of reference defined by the second catheter also enables the operator to navigate the first catheter around the interior of the heart without the need for simultaneous fluoroscopic or other imaging.
In some preferred embodiments of the present invention, arrhythmias and pathological cardiac events are detected, using methods known in the art, simultaneously with determining the velocity vectors in accordance with the method described above. Each velocity vector is classified and stored, preferably by computer 51 or other electronic data storage device, according to a type of cardiac arrhythmia or event (or normal heart beat) that occurred at the time the electrogram signals used to determine the vector were received. Stored vectors that have been classified as belonging to a specific arrhythmia or event are then used to generate a map of the propagation of electrical activation in the heart that is characteristic of that arrhythmia or event. Such maps may be useful, for example, in detecting abnormal propagation of the activation front that is associated with a specific arrhythmia, including cases in which multiple activation fronts pass a location in the heart during a single R-R cardiac cycle interval.
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International Classification A61B5/06, A61B19/00, A61N1/362, A61B, A61B5/042, A61N7/02, A61N5/06, A61N5/10, A61B17/00, A61B5/00, A61B5/04, A61B5/0492, A61N1/40, A61B5/0402, A61N1/32, A61B17/34, A61B5/029, A61B5/026, A61B5/0478, A61N1/365, A61B17/22, A61N1/05, A61B18/20, A61B17/32, A61B5/0215, A61N1/368, A61B5/0408, A61M25/00
Cooperative Classification A61B5/062, A61B18/20, A61B2562/043, A61N1/368, A61B2017/22008, A61B34/20, A61B2034/2051, A61N1/3627, A61B2090/3958, A61B2018/00291, A61B17/22012, A61B5/6859, A61B34/25, A61B2018/00392, A61N1/32, A61B8/0841, A61B5/029, A61M2025/0166, A61B5/145, A61N1/36564, A61B2017/00247, A61N1/40, A61B2017/00053, A61B2017/00694, A61B17/3403, A61B5/6843, A61N5/1064, A61B5/0215, A61N7/02, A61B10/02, A61B5/0422, A61B2562/0209, A61B5/6853, A61B5/6852, A61B5/06, A61B5/6858, A61B5/6856
European Classification A61B5/145, A61B5/68D1H1, A61B5/68B5, A61B5/68D1H5, A61B5/68D1H, A61B5/68D1H3, A61B5/68D1H6, A61B8/08H2, A61B19/52H12, A61B18/20, A61B17/34D, A61N1/362C, A61B5/029, A61N7/02, A61N1/32, A61B17/22B2, A61B5/042D, A61N1/40, A61B5/06, A61N1/365B9, A61B5/0215