Methods and systems for localizing reentrant circuits from electrogram features

• US 6,236,883 B1
• Filed: 02/03/1999
• Issued: 05/22/2001
• Est. Priority Date: 02/03/1999
• Status: Expired due to Fees

• Current Assignee: Trustees Of Columbia University In The City Of New York (Columbia University)
• Original Assignee: Trustees Of Columbia University In The City Of New York (Columbia University)
• Inventors: Wit, Andrew L., Ciaccio, Edward J.
• Primary Examiner(s): GETZOW, SCOTT M
• Application Number:
  US09/244,549
• Time in Patent Office: 839 Days
• Field of Search: 600/509, 600/515, 600/516, 600/517, 600/518
• US Class Current: 600/515
• CPC Class Codes: A61B 5/35 by template matching
• CPC Class Codes: A61B 5/363 Detecting tachycardia or bradycardia

Abstract

This invention provides a method comprising the steps of identifying and localizing reentrant circuits from electrogram features using feature detection and localization (FDL) algorithms. This invention provides the above method further comprising the steps of: a) using a contoured array of electrodes arranged in concentric circular patterns to obtain signals from the hearts surface to determine the direction and velocity of the activating wavefront at the catheter location; b) obtaining and preprocessing analog electrogram signals, digitizing the processed signals, and storing the digitized signals in real-time using a digital storage device; c) creating real-time maps and generating other textual information that are displayed on a computer screen, based on reentrant circuit features algorithms. This invention provides a system comprising a means for localizing reentrant circuits from electrogram features using reentrant circuit features algorithms.

Claims

1. A method of using feature detection and localization (FDL) algorithms for identifying and localizing reentrant circuits from electrogram features in a heart of a subject comprising the steps of:

a) using a contoured array of electrodes arranged in concentric circular patterns to obtain signals from the heart'"'"'s surface to determine direction and velocity of an activating wavefront at the catheter location;

b) obtaining and preprocessing analog electrogram signals, and then multiplexing and storing the signals in real time; and

c) creating real-time maps and generating other textual information based on feature detection and localization (FDL) algorithms so as to thereby identify and localize reentrant circuits from electrogram features in the heart of the subject.

2. The method of claim 1 for quantifying dynamic, beat-to-beat changes in electrogram morphology.

3. The method of claim 2, wherein signal segments are adaptively matched for best overlap.

4. The method of claim 2 for quantifying the linear parameter of electrogram shape.

5. The method of claim 1, wherein the method is used for quantifying a piecewise linear parameter of electrogram shape.

6. The method of claim 1, wherein the method is used for quantifying a non-linear parameter of electrogram shape.

7. The method of claim 1, wherein mean square error or other criteria is used for adaption of weights.

8. The method of claim 7, wherein the mean square error or other criteria measures cycle-to-cycle changes in intrinsic electrogram shape.

9. The method of claim 1, wherein each electrogram on each cardiac cycle is compared to a reference electrogram or template electrogram.

10. The method of claim 9, wherein the method is used to obtain information about changes in electrogram morphology which occur over multiple cardiac cycles from one cardiac cycle to the next cardiac cycle.

11. The method of claim 1, wherein functional lines of block are located using an ATM algorithm.

12. The method of claim 1 to locate reentrant circuits for surgical incision or catheter ablation in a subject with ventricular tachycardia.

13. The method of claim 1, wherein reentrant circuit features are identified and located for catheter ablation of ventricular tachycardia without the necessity for recording from a large number of sites and without constructing activation maps.

14. The method of claim 13, wherein a region of greatest increase of a PLATM duration parameter when tachycardia cycle length increases resides at a location where slow conduction occurs in a central common pathway of a reentrant circuit.

15. The method of claim 13, wherein a region of greatest decrease of a PLATM duration parameter when tachycardia cycle length decreases resides at a location where slow conduction occurs in the central common pathway of a reentrant circuit.

16. The method of claim 14 or 15, wherein the method is used to update a location of an ablation catheter based on far-field electrogram deflections.

17. The method of claim 16, wherein a PLATM phase shift parameter is used to determine time of activation of the zone of slow conduction with respect to a local activation time at the position of the catheter.

18. The method of claim 17, wherein a model is used to convert the time of activation into a direction and distance from the current position of the catheter to the zone of slow conduction.

19. The method of claim 13 wherein an NATM filter coefficient is used to distinguish activation occurring inside of a central common pathway from activation occurring outside of a central common pathway.

20. The method of claim 19 wherein waveforms are compared at different cycle lengths to determine changes in an NATM filter coefficient.

21. The method of claim 20, wherein the method is used to update the location of an ablation catheter based on electrogram far-field directions.

22. The method of claim 13, wherein a concentric circular multielectrode ring and a conduction velocity (CV) algorithm are used to determine wavefront speed and direction at the location of the catheter tip.

23. The method of claim 22, wherein the direction of wavefront propagation is calculated based on the conduction velocity algorithm using the maximum difference in activation time of any two or more electrodes.

24. The method of claim 23, wherein the direction of the block lines with respect to the catheter tip are perpendicular to the direction of wavefront propagation when the catheter resides within the central common pathway at the slow conduction zone.

25. The method of claim 23, wherein conduction velocity of an activating wavefront is determined by dividing the maximum difference or maximum average difference in activation time of any two or more electrodes into the distance or average distande between those electrodes.

26. The method of claim 13, wherein the center of the narrowest width of the central common pathway of reentrant circuits is determined using 5-500 ATM weight variability peaks.

27. The method of claim 26, wherein the center of mass of the highest 2-400 variance peaks is determined, thereby approximating the center of the narrowest central common pathway width location.

28. The method of claim 26, wherein the center of mass of an average of all 5-500 variance peaks from highest to lowest is determined, thereby approximating the center of the narrowest central common pathway width location.

29. The method of claim 1, wherein ablation of a central common pathway between lines of functional block at a zone of slow conduction prevents tachycardia.

30. The method of claim 4, wherein the linear parameter of electrogram shape is scale.

31. The method of claim 30, wherein the scale is amplitude.

32. The method of claim 30, wherein the scale is duration.

33. The method of claim 4, wherein the linear parameter is shift.

34. The method of claim 33, wherein the shift is average baseline.

35. The method of claim 33, wherein the shift is phase lag.

36. The method of claim 4, wherein the linear parameters are weighted by ramp function, sigmoidal function or step function in combination with uniform weighting.

37. The method of claim 5, wherein the piecewise linear parameter is scale.

38. The method of claim 37, wherein the scale is amplitude.

39. The method of claim 37, wherein the scale is duration.

40. The method of claim 5, wherein the piecewise linear parameter is shift.

41. The method of claim 40, wherein the shift is average baseline.

42. The method of claim 40, wherein the shift is phase lag.

43. The method of claim 5, wherein the piecewise linear parameter is weighted by ramp function, sigmoidal function, or step function in combination with uniform weighting.

44. The method of claim 6, wherein the non-linear parameter is a low pass filter coefficient.

45. The method of claim 6, wherein the non-linear parameter a high pass filter coefficient.

46. The method of claim 6, wherein the non-linear parameter is a notch pass filter coefficient.

47. The method of claim 6, wherein the non-linear parameter is a bandpass pass filter coefficient.

48. The method of claim 6, wherein the non-linear parameter is an exponential or other nonlinear coefficient.

49. The method of claim 6, wherein the non-linear parameter is weighted by ramp function, sigmoidal function or step function in combination with uniform weighting.

50. The method of claim 9, wherein the reference electrogram or template electrogram is obtained from a representative cycle.

51. The method of claim 9, wherein the reference electrogram or template electrogram is obtained from a combination of multiple cycles.

52. The method of claim 10, which uses a differential steepest descent method or other adaptive method to compute weight update.

53. The method of claim 52, wherein magnitude and direction for weight adjustment are determined by calculating a derivative or other function of error based on finite difference changes or other changes in weighting.

54. The method of claim 53, wherein the method minimizes a misadjustment of weight update.

55. The method of claim 53, wherein a convergence coefficient is optimized so as to minimize misadjustment of weight update.

56. The method of claim 55, wherein a convergence coefficient is incremented up or down so as to minimize mean square error or other error function during weight update.

57. The method of claim 53, wherein the number of data samples or length of segment are maximized so as to minimize misadjustment of weight update.

58. The method of claim 57, wherein maximum length of segment is between 50 milliseconds to 1000 milliseconds.

59. The method of claim 53, wherein finite difference is optimized so as to minimize misadjustment of weight update.

60. The method of claim 59, wherein finite difference is incremented up or down so as to minimize mean square error or other error function during weight update.

61. The method of claim 11, wherein functional lines of block in reentrant circuits are located by analyzing ATM variances or other weight variabilities from data obtained during sustained monomorphic ventricular tachycardia.

62. The method of claim 11, wherein functional lines of block in reentrant circuits are located by analyzing ATM variances or other weight variabilities from data obtained during unsustained monomorphic ventricular tachycardia.

63. The method of claim 11, wherein functional lines of block in reentrant circuits are located by analyzing ATM variances or other weight variabilities from data obtained during polymorphic ventricular tachycardia.

64. The method of claim 11, wherein functional lines of block in reentrant circuits are located by analyzing ATM variances or other weight variabilities from data obtained during sinus rhythm.

65. The method of claim 11, wherein functional lines of block in reentrant circuits are located by analyzing ATM variances or other weight variabilities from data obtained during ventricular pacing during sinus rhythm.

66. The method of claim 11, wherein functional lines of block in reentrant circuits are located by analyzing ATM variances or other weight variabilities from data obtained during pacing during ventricular tachycardia.

67. The method of claim 11, wherein analysis is performed by computer processing.

68. The method of claim 1, wherein regions of greatest variance of ATM parameters are adjacent to the location of functional lines of block which form boundaries of the central common pathway in reentrant circuits.

69. The method of claim 68, wherein a combination of variances for sites with low variance is used as a threshold.

70. The method of claim 13 wherein changes in a PLATM parameter when tachycardia cycle length changes reside at a location where slow conduction occurs in the central common pathway of a reentrant circuit.

71. The system of claim 70, wherein the PLATM parameter is duration, phase lag, amplitude or average baseline.

72. The method of claim 16, wherein a PLATM duration parameter is used to determine time of activation of a zone slow conduction with respect to a current position of the catheter.

73. The method of claim 72, wherein a model is used to convert time of activation into a direction and distance from a current position of the catheter to the zone of slow conduction.

74. The method of claim 73, wherein a location of the catheter tip can be directed toward a location of the optimal site to ablate the heart based on distance from the catheter tip to the slow conduction zone (SCZ) proximal and distal borders.

75. The method of claim 13, wherein a slow conduction zone in reentrant circuits can be located by analyzing PLATM parameters from data obtained during unsustained monomorphic ventricular tachycardia.

76. The method of claim 13, wherein a slow conduction zone in reentrant circuits can be located by analyzing PLATM parameters from data obtained during polymorphic ventricular tachycardia.

77. The method of claim 13, wherein a slow conduction zone in reentrant circuits can be located by analyzing PLATM parameters from data obtained during sinus rhythm.

78. The method of claim 13, wherein a slow conduction zone in reentrant circuits can be located by analyzing PLATM parameters from data obtained during ventricular pacing during sinus rhythm.

79. The method of claim 13, wherein a slow conduction zone in reentrant circuits can be located by analyzing PLATM parameters from data obtained during pacing during ventricular tachycardia.

80. The method of claim 13, wherein analysis is performed by computer processing.

81. The method of claim 21, wherein the catheter tip location is directed toward an optimal site to ablate the heart based on a distance from the catheter tip to the central common pathway entrance and exit.

82. The method of claim 21, wherein an NATM filter coefficient change when cycle length changes is used to determine time of activation of the borders of the central common pathway'"'"'s entrance and exit with regard to local activation time at the portion of the catheter.

83. The method of claim 82, wherein a model is used to determine distance from the local site to the central common pathway'"'"'s entrance and exit.

84. The method of claim 83, wherein the length of the central common pathway'"'"'s length and the length of the bounding block lines are determined based on the distances from the catheter tip to the central common pathway entrance and exit.

85. The method of claim 84, wherein the central common pathway'"'"'s location and length and bounding block lines'"'"' length are determined by analyzing NATM coefficients from data obtained during sustained monomorphic ventricular tachycardia.

86. The method of claim 84, wherein the central common pathway'"'"'s location and bounding block lines'"'"' length are determined by analyzing NATM coefficients from data obtained during unsustained monomorphic ventricular tachycardia.

87. The method of claim 84, wherein the central common pathway'"'"'s location and length and bounding block lines'"'"' length are determined by analyzing NATM coefficients from data obtained during polymorphic ventricular tachycardia.

88. The method of claim 84, wherein the central common pathway'"'"'s location and length and bounding block lines'"'"' length are determined by analyzing NATM coefficients from data obtained during sinus rhythm.

89. The method of claim 84, wherein the central common pathway'"'"'s location and length and bounding block lines'"'"' length are determined by analyzing NATM coefficients from data obtained during ventricular pacing during sinus rhythm.

90. The method of claim 84, wherein the central common pathway'"'"'s location and length and bounding block lines'"'"' length are determined by analyzing ATM variances or other weight variabilities from data obtained during ventricular pacing during ventricular tachycardia.

91. The method of claim 26, wherein a narrowest central common pathway width location can be located by using center of mass data obtained during sustained monomorphic ventricular tachycardia.

92. The method of claim 26, wherein a narrowest central common pathway width location can be located by using center of mass data obtained during polymorphic ventricular tachycardia.

93. The method of claim 26, wherein a narrowest central common pathway width location can be located by using center of mass data obtained during sinus rhythm.

94. The method of claim 26, wherein center of mass width location can be located by using center of mass data obtained during ventricular pacing during sinus rhythm.

95. The method of claim 26, wherein center of mass width location can be located by using center of mass data obtained during ventricular pacing during ventricular tachycardia.

96. The method of claim 1, further comprising ablating a heart to stop ventricular tachycardia when pattern of reentry is that of a single loop or of multiple loops.

97. The method of claim 1 further comprising ablating a heart to stop ventricular tachycardia when lines of block around which activating wavefront traverses are anatomical, partially anatomical, or functional.

98. The method of claim 1 further comprising ablating a heart to stop ventricular tachycardia when pattern of reentry is intramural or transmural.

99. The method of claim 1 wherein the method is used to pinpoint sites or specific areas for drug delivery.

100. The method of claim 1 wherein the method is used to detect and localize pathologic conditions in a heart, brain, lung, gastroinestinal system, musculoskeletal system or other system.

101. The method of claim 1, wherein the real time maps and other textual information are displayed on a computer screen.

102. A system for identifying and localizing reentrant circuits from electrogram features in a heart of a subject using feature detection and localization (FDL) algorithms which comprises:

a) a multipolar ring electrode catheter which uses a contoured array of electrodes arranged in concentric circular patterns to obtain signals from the heart'"'"'s surface to determine the speed and direction and velocity of an activating wavefront at the catheter location;

b) a data acquisition subsystem for obtaining and preprocessing analog electrogram signals, and for multiplexing and storing the signal in real-time, either in analog or digital form;

c) a processing unit comprising software and hardware for using multiple electrode signals, and feature detection and localization (FDL) algorithms; and

d) a display/guidance subsystem for creating real-time maps and generating other textual information based on reentrant circuit features algorithms.

103. The system of claim 102, wherein the multipolar ring electrode catheter comprises electrodes attached to wires at a tip of the catheter for recording electrogram signals and for ablating the heart from any of the electrodes.

104. The system of claim 103, wherein the wires are insulated.

105. The system of claim 103, wherein the wires are shielded.

106. The system of claim 103, wherein the wires are thin.

107. The system of claim 102, wherein the multipolar ring electrode catheter comprises a configuration of electrodes in concentric circular patterns.

108. The system of claim 107, wherein the configuration of electrodes in concentric circular patterns are located at a tip of the catheter.

109. The system of claim 108, wherein the electrodes record electrogram signals and ablate the heart with radiofrequency or other energy.

110. The system of claim 102, wherein the multipolar ring electrode catheter comprises an electrode array.

111. The system of claim 110, wherein the electrode array is conical-shaped.

112. The system of claim 110, wherein the electrode array is capable of being folded.

113. The system of claim 112 wherein the electrode array is capable of being folded in a fan-like folding action.

114. The system of claim 112, wherein the electrode array is folded when located in a human artery.

115. The system of claim 112, wherein the electrode array is opened into a conical-shape when located in a ventricular cavity of the heart so as to fit the contour of the heart.

116. The system of claim 102, wherein the multipolar ring electrode catheter comprises a catheter shell.

117. The system of claim 116, wherein the catheter shell is flexible.

118. The system of claim 116, wherein the catheter shell contains wires.

119. The system of claim 118, wherein the wires are used to record electrograms and to ablate the heart.

120. The system of claim 102, wherein the multipolar ring electrode catheter comprises a terminal mount.

121. The system of claim 120, wherein the terminal mount is used to connect and disconnect the catheter at its end which is proximal to the data acquisition subsystem.

122. The system of claim 102, wherein the data acquisition subsystem comprises circuitry.

123. The system of claim 122, wherein the circuitry amplifies signals so as to thereby reduce noise pickup.

124. The system of claim 122, wherein the circuitry increases voltage resolution of the digitized signals.

125. The system of claim 122, wherein the circuitry low pass filters signals so as to thereby prevent aliasing during digitization.

126. The system of claim 122, wherein the circuitry high pass filters signals so as to prevent buildup of bias voltage and prevent motion artifacts.

127. The system of claim 122, wherein the circuitry mutiplexes and stores electrogram signals.

128. The system of claim 127, wherein the electrogram signals are stored in analog form.

129. The system of claim 127, wherein the electrogram signals are stored in digital form.

130. The system of claim 102, wherein the processing unit comprises algorithms for identification and location of reentrant circuit features.

131. The system of claim 102, wherein the algorithms are hardwired using analog circuitry for serial or parallel processing.

132. The system of claim 102, wherein the algorithms are hardwired using integrated circuits for serial or parallel processing.

133. The system of claim 102, wherein the algorithms are downloaded to programmable logic array integrated circuits for serial or parallel processing.

134. The system of claim 102, wherein the algorithms are written in software code for serial or parallel processing using a microprocessor or parallel processing using multiple microprocessors.

135. The system of claim 102, wherein the display/guidance subsystem displays wavefront, speed, direction and conduction velocity.

136. The system of claim 135, wherein the wavefront, speed, direction and conduction velocity are determined based on electrogram signals obtained from the multipolar electrode array and the conduction velocity algorithm.

137. The system of claim 136, wherein location of block lines is determined based on measurements made using an ATM algorithm.

138. The system of claim 136, wherein direction of the slow conduction zone with respect to catheter location is determined based on measurements made using a PLATM algorithm.

139. The system of claim 136, wherein distance to proximal and distal borders of the slow conduction zone with respect to the catheter location is determined.

140. The system of claim 136, wherein the central common pathway'"'"'s entrance and exit are located based on measurements made using an NATM algorithm.

141. The system of claim 136, wherein lengths of bounding functional line of block are determined based on measurements made using an NATM algorithm.

142. The system of claim 136, for locating a narrowed width of the central common pathway based on a center of mass algorithm.

143. The system of claim 136, which further comprises a system of symbols which den te features of the reentrant circuit on a real-time display map.

144. The system of claim 143, wherein the system of symbols comprises shaded and extured shapes.

145. The system of claim 136, which further comprises a system of symbols which denote distance and directional information pertaining to a location of reentrant circuit features with respect to a location of the catheter on a real-time display map.

146. The system of claim 145, wherein the system of symbols comprises arrows and angles.

147. The system of claim 136, wherein maps and textual information are updated in near-real time based on reentrant circuit feature algorithms and on new data obtained at each new site at which the catheter tip is positioned.

148. The system of claim 147, wherein the maps and textual information are updated on the display screen.

149. The system of claim 102 for ablating the heart to stop ventricular tachycardia when the pattern of reentry is a single loop or multiple loops.

150. The system of claim 102 for ablating the heart to stop ventricular tachycardia when lines of block around which an activating wavefront traverses are anatomical.

151. The system of claim 102 which uses sensors other than electrodes selected from the group consisting of magnetometers, microphones, pressure transducers, thermistors, charge-coupled diode arrays, or gas analyzers.

152. The system of claim 151, wherein the sensors obtain signal or image information for detection and localization of pathologic conditions in the heart, brain, lung, gastroinestinal system or musculoskeletal system.

153. The system of claim 102, wherein the real time maps and other textual information are displayed on a computer screen.

154. The system of claim 153, wherein the computer screen is touch sensitive.

155. The system of claim 102, for ablating the heart to stop ventricular tachycardia when the pattern of reentry is intramural or transmural.

156. The system of claim 102 for pinpointing sites or specific areas for drug delivery.

157. The system of claim 102 used to detect and localize pathologic conditions in the heart, brain, lung, gastrointestinal system, musculoskeletal system and other systems.