Methods and apparatuses for localizing myocardial infarction during catheterization

• US 20050283195A1
• Filed: 06/18/2004
• Published: 12/22/2005
• Est. Priority Date: 06/18/2004
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Pastore, Joseph M., Girouard, Steven D.
• Granted Patent: US 7,640,046 B2
• Time in Patent Office: Days
• US Class Current: 607/4
• CPC Class Codes: A61B 2562/0219 Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches
• CPC Class Codes: A61B 5/0071 by measuring fluorescence emission
• CPC Class Codes: A61B 5/0084 for introduction into the body, e.g. by catheters A61B5/1459 takes precedence
• CPC Class Codes: A61B 5/0265 using electromagnetic means, e.g. electromagnetic flowmeter
• CPC Class Codes: A61B 5/1107 Measuring contraction of parts of the body, e.g. organ, muscle apparatus for measuring work or force in general G01L
• CPC Class Codes: A61B 5/4839 combined with drug delivery
• CPC Class Codes: A61B 5/6869 Heart
• CPC Class Codes: A61B 8/12 in body cavities or body tracts, e.g. by using catheters catheters per se A61M25/00
• CPC Class Codes: A61N 1/3702 Physiological parameters A61N1/365 takes precedence; evoked response A61N1/371

Abstract

A catheter with a tissue property sensor provides for localization of myocardial infarction (MI) by utilizing one or more differences between properties of infarcted myocardial tissue and properties of normal myocardial tissue. The tissue property sensor is to be placed on endocardial wall or epicardial wall during catheterization to sense at least one tissue property allowing for detection of MI. Examples of the tissue property sensor include, but are not limited to, an optical sensor, an acoustic sensor, a contractility sensor, a temperature sensor, and a drug response sensor. In one embodiment, the tissue property sensor senses a tissue property in various locations on endocardial wall or epicardial wall and detects substantial changes in the tissue property that indicate a boundary between infarcted tissue and normal tissue.

Claims

1. A system for localizing myocardial infarction (MI) in a heart having a cardiac wall, the system comprising:

a catheter including a distal end configured for placement in a location on the cardiac wall;

a myocardial tissue property sensor incorporated into the distal end of the catheter and adapted to be placed in a myocardial location to sense a signal indicative of at least one tissue property, the myocardial tissue property sensor selected from a group consisting of an optical sensor, an acoustic sensor, a contractility sensor, a temperature sensor, and a drug response sensor; and

a tissue property analyzer including an input to receive the sensed signal and an output indicative of whether the sensed signal indicates infarcted tissue.

2. The system of claim 1, wherein the distal end of the catheter is configured for placement in a location on an endocardial wall.

3. The system of claim 1, wherein the distal end of the catheter is configured for placement in a location on an epicardial wall.

4. The system of claim 1, wherein the tissue property analyzer comprises a parameter generator to produce a parameter based on the sensed signal.

5. The system of claim 4, wherein the tissue property analyzer further comprises a comparator including a signal input receiving the parameter, a threshold input receiving a predetermined threshold, and an output indicating a detection of infarcted tissue based on a comparison between the signal and the threshold.

6. The system of claim 1, wherein the myocardial tissue property sensor is adapted to be placed in a plurality of locations, one at a time, over at least a portion of the cardiac wall to sense signals each indicative of at least one tissue property associated with one of the plurality of locations.

7. The system of claim 6, wherein the tissue property analyzer comprises a tissue property mapping module to produce a tissue property map presenting a measure of the at least one tissue property over the at least the portion of the cardiac wall based on the sensed signals.

8. The system of claim 7, wherein the tissue property analyzer further comprises a myocardial infarction detector to detect one or more infarcted regions based on the tissue property map.

9. The system of claim 1, wherein the catheter comprises a diagnostic catheter adapted for assessment of hemodynamic function.

10. The system of claim 1, wherein the catheter comprises a diagnostic catheter adapted for mapping of cardiovascular structure.

11. The system of claim 1, wherein the catheter comprises a substance-delivery catheter.

12. The system of claim 1, wherein the catheter comprises an ablation catheter.

13. The system of claim 1, wherein the catheter comprises a pacing lead.

14. The system of claim 1, wherein the catheter comprises a defibrillation lead.

15. A system for localizing myocardial infarction (MI) in a heart having a cardiac wall, the system comprising:

a catheter including a distal end configured for placement in a location on the cardiac wall;

a myocardial tissue property sensor incorporated into the distal end of the catheter and adapted to be placed in a myocardial location, the myocardial tissue property including an optical sensor including;

an optical transmitter to emit a light; and

an optical receiver to receive an optical signal related to the emitted light, the optical signal indicative of a tissue property; and

a tissue property analyzer including an input to receive the optical signal and an output indicative of whether the optical signal indicates infarcted tissue.

16. The system of claim 15, wherein the catheter comprises a lumen allowing injection of a fluorescent dye through the lumen, the fluorescent dye sensitive to transmembrane potentials.

17. The system of claim 16, wherein the catheter comprises a lead extending through at least a portion of the catheter and an electrode at or near the distal end, the electrode connected to the lead to allow delivery of electrical stimuli.

18. The system of claim 15, wherein the tissue property analyzer comprises a wavelength analyzer to produce an optical spectrum of the optical signal.

19. The system of claim 18, wherein the tissue property analyzer further comprises an MI detector to detect the infarcted tissue based on the optical spectrum.

20. The system of claim 19, wherein the MI detector is adapted to detect the infarcted tissue by comparing the optical spectrum to a template spectrum.

21. The system of claim 19, wherein the MI detector is adapted to detect the infarcted tissue based on a substantial change in the optical spectrum when the optical sensor is moved from one myocardial location to another myocardial location.

22. A system for localizing myocardial infarction (MI) in a heart having a cardiac wall, the system comprising:

a catheter including a distal end configured for placement in a location on the cardiac wall;

a myocardial tissue property sensor incorporated into the distal end of the catheter and adapted to be placed in a myocardial location, the myocardial tissue property sensor including an acoustic sensor including;

an acoustic transmitter to emit an acoustic energy; and

an acoustic receiver to receive an acoustic signal related to the emitted acoustic energy, the acoustic signal indicative of a tissue property; and

a tissue property analyzer including an input to receive the acoustic signal and an output indicative of whether the acoustic signal indicates infarcted tissue.

23. The system of claim 22, wherein the acoustic transmitter comprises a speaker to transmit an audible sound.

24. The system of claim 22, wherein the acoustic transmitter comprises an ultrasound transmitter to transmit an ultrasound.

25. The system of claim 22, wherein the acoustic transmitter comprises a piezoelectric crystal.

26. The system of claim 22, wherein the tissue property analyzer comprises a frequency analyzer to produce an acoustic spectrum of the received acoustic signal.

27. The system of claim 26, wherein the tissue property analyzer further comprise an MI detector to detect the infarcted tissue based on the acoustic spectrum.

28. The system of claim 27, wherein the MI detector is adapted to detect the infarcted tissue by comparing the acoustic spectrum to a template spectrum.

29. The system of claim 27, wherein the MI detector is adapted to detect the infarcted tissue based on a substantial change in the acoustic spectrum when the acoustic sensor moves from one myocardial location to another myocardial location.

30. A system for localizing myocardial infarction (MI) in a heart having a cardiac wall, the system comprising:

a catheter including a distal end configured for placement in a location on the cardiac wall;

a myocardial tissue property sensor incorporated into the distal end of the catheter and adapted to be placed in a myocardial location, the myocardial tissue property sensor including a contractility sensor being an accelerometer array including a plurality of accelerometers to sense acceleration signals each indicative of a tissue property; and

a tissue property analyzer including an input to receive the acceleration signals and an output indicative of whether the acceleration signals indicate infarcted tissue.

31. The system of claim 30, wherein the contractility senor is adapted to sense the acceleration signals from a plurality of myocardial locations constituting a myocardial region.

32. The system of claim 31, wherein the tissue property analyzer comprises a motion pattern analyzer to produce a cardiac wall motion pattern for the myocardial region based on the sensed acceleration signals.

33. The system of claim 32, wherein the contractility sensor is adapted to be placed in a plurality of myocardial regions, one at a time, over at least a portion of a cardiac wall, and wherein the tissue property analyzer further comprises a mapping module to produce a contractility map presenting cardiac wall motion patterns for the at least the portion of a cardiac wall.

34. The system of claim 33, wherein the tissue property analyzer further comprises an MI detector adapted to detect the infarcted tissue based on the contractility map.

35. A system for localizing myocardial infarction (MI) in a heart having a cardiac wall, the system comprising:

a catheter including a distal end configured for placement in a location on the cardiac wall;

a myocardial tissue property sensor incorporated into the distal end of the catheter and adapted to be placed in a myocardial location, the myocardial tissue property sensor including a temperature sensor including;

a thermal transmitter to emit a thermal energy; and

a thermometer to sense a temperature signal related to the emitted thermal energy, the temperature indicative of a tissue property; and

a tissue property analyzer including an input to receive the temperature signal and an output indicative of whether the temperature signal indicates infarcted tissue.

36. The system of claim 35, wherein the catheter includes a lumen allowing injection of thermal dilution liquid through the lumen.

37. The system of claim 35, wherein the tissue property analyzer comprises a thermal perfusion analyzer to produce a rate of temperature change based on the temperature signal, the rate of temperature change being a change in a temperature over a predetermined period of time.

38. The system of claim 37, wherein the tissue property analyzer further comprises an MI detector adapted to detect the infarcted tissue based on the rate of temperature change.

39. The system of claim 38, wherein the MI detector is adapted to detect the infarcted tissue by comparing the rate of temperature change to a template rate.

40. The system of claim 38, wherein the MI detector is adapted to detect the infarcted tissue based on a substantial change in the rate of temperature change when the temperature sensor moves from one myocardial location to another myocardial location.

41. A system for localizing myocardial infarction (MI) in a heart having a cardiac wall, the system comprising:

a catheter including a distal end configured for placement in a location on the cardiac wall;

a myocardial tissue property sensor incorporated into the distal end of the catheter and adapted to be placed in a myocardial location, the myocardial tissue property sensor including a drug response sensor including;

a drug delivery device to deliver a drug; and

a drug response detector to detect a signal indicative of a tissue response to the delivered drug; and

a tissue property analyzer including an input to receive the signal and an output indicative of whether the signal indicates infarcted tissue.

42. The system of claim 41, wherein the drug comprises one of isoproterenol, dobutamine, nitroglycerin, and brain natriuretic peptide (BNP).

43. The system of claim 41, wherein the catheter comprises a lumen allowing injection of the drug through the lumen.

44. The system of claim 41, wherein the tissue property analyzer comprises a drug response analyzer to produce a tissue response parameter based on the signal indicative of the tissue response.

45. The system of claim 44, wherein the tissue property analyzer further comprises an MI detector adapted to detect the infarcted tissue based on the tissue response parameter.

46. The system of claim 45, wherein the MI detector is adapted to detect the infarcted tissue by comparing the tissue response parameter to a template tissue response parameter.

47. The system of claim 45, wherein the MI detector is adapted to detect the infarcted tissue based on a substantial change in the tissue response parameter when the drug response sensor moves from one myocardial location to another myocardial location.

48. The system of claim 41, wherein the drug comprises an agent changing contractility of myocardial tissue.

49. The system of claim 48, wherein the drug response detector comprises a contractility sensor to sense a signal indicative of the contractility of myocardial tissue.

50. The system of claim 49, wherein the contractility sensor comprises an accelerometer.

51. The system of claim 50, wherein the drug includes isoproterenol.

52. The system of claim 50, wherein the tissue property analyzer comprises a displacement analyzer to produce a parameter indicative of a cardiac wall displacement.

53. The system of claim 52, wherein the tissue property analyzer further comprises an MI detector to detect the infarcted tissue based on parameter indicative of the cardiac wall displacement.

54. The system of claim 41, wherein the drug response detector comprises a drug concentration sensor.

55. The system of claim 54, wherein the drug comprises nitroglycerin.

56. The system of claim 54, wherein the tissue property analyzer comprises a drug perfusion analyzer to produce a rate of drug perfusion being a change in the sensed drug concentration over a predetermined period of time.

57. The system of claim 56, wherein the tissue property analyzer further comprises an MI detector adapted to detect infarcted tissue based on the rate of drug perfusion.

58. A system for localizing myocardial infarction (MI), the system comprising:

a catheter including a distal end configured for myocardial placement;

a myocardial tissue property sensor incorporated into the distal end of the catheter and adapted to be placed in a myocardial location to sense a signal indicative of at least one tissue property; and

a tissue property analyzer receiving the sensed signal, the tissue property analyzer including;

a parameter generator to produce a parameter based on the sensed signal; and

a comparator including a signal input receiving the parameter, a threshold input receiving a predetermined threshold, and an output indicating a detection of infarcted tissue based on a comparison between the parameter and the threshold.

59. The system of claim 58, wherein the distal end of the catheter is configured for endocardial placement.

60. The system of claim 58, wherein the distal end of the catheter is configured for epicardial placement.

61. The system of claim 58, wherein the myocardial tissue property sensor comprises an optical sensor.

62. The system of claim 61, wherein the optical sensor comprises:

an optical transmitter to emit a light; and

an optical receiver to receive an optical signal related to the emitted light.

63. The system of claim 58, wherein the myocardial tissue property sensor comprises an acoustic sensor.

64. The system of claim 63, wherein the acoustic sensor comprises:

an acoustic transmitter to emit an acoustic energy; and

an acoustic receiver to receive an acoustic signal related to the emitted acoustic energy.

65. The system of claim 58, wherein the myocardial tissue property sensor comprises a myocardial contractility sensor.

66. The system of claim 65, wherein the contractility sensor comprises a plurality of accelerometers.

67. The system of claim 58, wherein the myocardial tissue property sensor comprises a temperature sensor.

68. The system of claim 67, wherein the temperature sensor comprises:

a thermal transmitter to emit a thermal energy; and

a thermometer to sense a temperature related to the emitted thermal energy.

69. The system of claim 58, wherein the myocardial tissue property sensor comprises a drug response sensor to sense a signal indicative of a myocardial tissue response to a drug delivery.

70. The system of claim 69, wherein the drug response sensor comprises:

a drug delivery device to deliver the drug; and

a drug response detector to detect a signal indicative of a tissue response to the delivered drug.

71. A system for localizing myocardial infarction (MI), the system comprising:

a catheter including a distal end configured for myocardial placement;

a myocardial tissue property sensor adapted to sense a signal indicative of at least one tissue property, the myocardial tissue property sensor incorporated into the distal end of the catheter and adapted to be placed in a plurality of myocardial locations, one at a time, over at least a portion of a cardiac wall to sense signals each indicative of the at least one tissue property for one of the plurality of myocardial locations;

a tissue property analyzer receiving the sensed signals, the tissue property analyzer including a tissue property mapping module adapted to produce a tissue property map presenting a measure of the at least one tissue property over the at least the portion of the cardiac wall based on the sensed signals.

72. The system of claim 71, wherein the distal end of the catheter is configured for endocardial placement.

73. The system of claim 71, wherein the distal end of the catheter is configured for epicardial placement.

74. The system of claim 71, wherein the tissue property analyzer further comprises a myocardial infarction detector to detect one or more infarcted regions based on the tissue property map.

75. The system of claim 71, wherein the myocardial tissue property sensor comprises an optical sensor.

76. The system of claim 75, wherein the optical sensor comprises:

an optical transmitter to emit a light; and

an optical receiver to receive an optical signal related to the emitted light.

77. The system of claim 71, wherein the myocardial tissue property sensor comprises an acoustic sensor.

78. The system of claim 77, wherein the acoustic sensor comprises:

an acoustic transmitter to emit an acoustic energy; and

an acoustic receiver to receive an acoustic signal related to the emitted acoustic energy.

79. The system of claim 71, wherein the myocardial tissue property sensor comprises a myocardial contractility sensor.

80. The system of claim 79, wherein the contractility sensor comprises a plurality of accelerometers.

81. The system of claim 71, wherein the myocardial tissue property sensor comprises a temperature sensor.

82. The system of claim 81, wherein the temperature sensor comprises:

a thermal transmitter to emit a thermal energy; and

a thermometer to sense a temperature related to the emitted thermal energy.

83. The system of claim 71, wherein the myocardial tissue property sensor comprises a drug response sensor to sense a signal indicative of a myocardial tissue response to a drug delivery.

84. The system of claim 83, wherein the drug response sensor comprises:

a drug delivery device to deliver the drug; and

a drug response detector to detect a signal indicative of a tissue response to the delivered drug.

85. A method for localizing myocardial infarction (MI) in a heart having a cardiac wall, the method comprising:

introducing a catheter including a sensor to provide for access to the heart, placing the sensor in a myocardial location;

sensing an signal using the sensor, the signal indicative of at least one tissue property in the myocardial location, the signal selected from a group consisting of an optical signal, an acoustic signal, a signal indicative of myocardial contractility, a temperature signal, and a signal indicative of a myocardial tissue response to a drug delivery; and

detecting infarcted tissue based on the signal.

86. The method of claim 85, wherein detection the infarcted tissue comprises:

producing a parameter representative of the at least one tissue property;

comparing the parameter to a predetermined threshold value; and

determining whether tissue in the myocardial location is infarcted based on the comparing.

87. The method of claim 85, further comprising:

sensing signals in a plurality of myocardial locations within at least a portion of the cardiac wall, the signals each indicative of the at least one tissue property in one location of the plurality of myocardial locations; and

producing a parameter representative of the at least one tissue property for each location of the plurality of myocardial locations.

88. The method of claim 87, further comprising:

comparing the measure of the at least one tissue property for the each location to a predetermined threshold value; and

detecting whether tissue in the each location is infarcted based on the comparing.

89. The method of claim 87, further comprising:

producing a tissue property map presenting the measure of the at least one tissue property over the at least the portion of the cardiac wall; and

detecting one or more infarcted regions based on the tissue property map.

90. The method of claim 89, wherein detecting the one or more infarcted regions comprises identifying where substantial changes in the measure of the at least one tissue property occur on the tissue property map.

91. A method for localizing myocardial infarction (MI) in a heart, the method comprising:

placing an optical sensor in a myocardial location;

emitting a light from the optical sensor;

receiving an optical signal related to the emitted light, the optical signal indicative of a tissue property in the myocardial location; and

detecting infarcted tissue based on the optical signal.

92. The method of claim 91, further comprising injecting a fluorescent dye sensitive to transmembrane potentials to the myocardial location.

93. The method of claim 91, further comprising delivering subthreshold electrical stimuli to the myocardial location.

94. The method of claim 91, wherein detecting the infarcted tissue comprises:

producing an optical spectrum of the received optical signal; and

detecting the infarcted tissue based on the optical spectrum.

95. The method of claim 94, wherein detecting the infarcted tissue comprises detecting the infarcted tissue when the optical spectrum differs from a template spectrum by a predetermined margin.

96. The method of claim 94, wherein detecting the infarcted tissue comprises detecting the infarcted tissue when the optical spectrum matches a template spectrum within a predetermined margin.

97. The method of claim 94, further comprising repeating the emitting the light, receiving the optical signal, and producing the optical spectrum for a plurality of myocardial locations, wherein detecting the infarcted tissue comprises detecting the infarcted tissue based on the optical spectra produced for the plurality of myocardial locations.

98. The method of claim 97, wherein detecting the infarcted tissue further comprises detecting an infarcted tissue region including one or more myocardial locations of the plurality of myocardial locations when the optical spectra for the myocardial locations adjacent to the one or more myocardial locations are substantially different from the optical spectra for the one or more myocardial locations.

99. A method for localizing myocardial infarction (MI) in a heart, the method comprising:

placing an acoustic sensor in a myocardial location;

emitting an acoustic energy from the acoustic sensor;

receiving an acoustic signal related to the emitted acoustic energy, the acoustic signal indicative of a tissue property in the myocardial location; and

detecting infarcted tissue based on the acoustic signal.

100. The method of claim 99, wherein emitting the acoustic energy comprises transmitting an audible sound.

101. The method of claim 99, wherein emitting the acoustic energy comprises transmitting an ultrasound.

102. The method of claim 99, wherein detecting the infarcted tissue comprises:

producing an acoustic spectrum of the received acoustic signal; and

detecting the infarcted tissue based on the acoustic spectrum.

103. The method of claim 102, wherein detecting the infarcted tissue further comprises detecting the infarcted tissue when the acoustic spectrum differs from a template spectrum by a predetermined margin.

104. The method of claim 102, wherein detecting the infarcted tissue further comprises detecting the infarcted tissue when the acoustic spectrum matches a template spectrum within a predetermined margin.

105. The method of claim 102, further comprising repeating the emitting the acoustic energy, receiving the acoustic signal, and producing the acoustic spectrum for a plurality of myocardial locations, wherein detecting the infarcted tissue further comprises detecting the infarcted tissue based on the acoustic spectra produced for the plurality of myocardial locations.

106. The method of claim 105, wherein detecting the infarcted tissue further comprises detecting an infarcted tissue region including one or more myocardial locations of the plurality of myocardial locations when the acoustic spectra for the myocardial locations adjacent to the one or more myocardial locations are substantially different from the acoustic spectra for the one or more myocardial locations.

107. A method for localizing myocardial infarction (MI) in a heart having a cardiac wall, the method comprising:

placing an accelerometer array on the cardiac wall;

sensing a plurality of acceleration signals indicative of myocardial contractility; and

detecting infarcted tissue on the cardiac wall based on the plurality of acceleration signals.

108. The method of claim 107, wherein sensing the plurality of acceleration signals comprises sensing the plurality of acceleration signals from a plurality of myocardial locations on the cardiac wall, the myocardial locations constituting a myocardial region.

109. The method of claim 108, wherein detecting the infarcted tissue comprises producing a cardiac wall motion pattern for the myocardial region based on the plurality of acceleration signals.

110. The method of claim 108, wherein detecting the infarcted tissue further comprises:

producing a contractility map representing cardiac wall motion patterns for a plurality of myocardial regions; and

detecting the infarcted tissue based on the contractility map.

111. The method of claim 110, wherein detecting the infarcted tissue based on the contractility map comprises identifying dyskinetic or hypokinetic regions on the contractility map.

112. The method of claim 111, wherein detecting the infarcted tissue based on the contractility map comprises identifying one or more regions of the plurality of myocardial regions associated with cardiac wall displacements that are substantially smaller than cardiac wall displacements of other regions of the of the plurality of myocardial regions.

113. A method for localizing myocardial infarction (MI) in a heart, the method comprising:

placing a thermal sensor in a myocardial location;

emitting a thermal energy from the thermal sensor;

sensing a temperature signal related to the emitted thermal energy, the temperature signal indicative of a tissue property in the myocardial location; and

detecting infarcted tissue based on the temperature signal.

114. The method of claim 113, wherein emitting the thermal energy comprises emitting a thermal energy to raise a temperature in the myocardial location.

115. The method of claim 113, wherein emitting the thermal energy comprises emitting a thermal energy to lower a temperature in the myocardial location.

116. The method of claim 113, wherein emitting the thermal energy comprises injecting the thermal dilution liquid.

117. The method of claim 116, wherein detecting the infarcted tissue comprises measuring a rate of temperature change from the temperature signal, the rate of temperature change being a change in a temperature over a predetermined period of time.

118. The method of claim 116, wherein detecting the infarcted tissue further comprises detecting the infarcted tissue when the rate of temperature change differs from a template rate by a predetermined margin.

119. The method of claim 116, wherein detecting the infarcted tissue further comprises detecting the infarcted tissue when the rate of temperature change matches a template spectrum within a predetermined margin.

120. The method of claim 116, further comprising repeating the emitting the thermal energy, sensing the temperature, and measuring the rate of temperature change for a plurality of myocardial locations, wherein detecting the infarcted tissue comprises detecting the infarcted tissue based on the rate of temperature change measured for the plurality of myocardial locations.

121. The method of claim 120, wherein detecting the infarcted tissue comprises detecting an infarcted tissue region including one or more myocardial locations of the plurality of myocardial locations when the rates of temperature change for the myocardial locations adjacent to the one or more myocardial locations are substantially different from the rates of temperature change for the one or more myocardial locations.

122. A method for localizing myocardial infarction (MI) in a heart, the method comprising:

placing a drug response sensor in a myocardial location;

delivering a drug from the drug response sensor;

detecting a signal indicative of a tissue response to the delivered drug; and

detecting infarcted tissue based on the signal indicative of the tissue response.

123. The method of claim 122, wherein delivering the drug comprises delivering one of isoproterenol, dobutamine, nitroglycerin, and brain natriuretic peptide (BNP).

124. The method of claim 122, wherein detecting the infarcted tissue comprises producing a tissue response parameter based on the signal indicative of the tissue response.

125. The method of claim 124, wherein detecting the infarcted tissue further comprises detecting the infarcted tissue when the tissue response parameter differs from a template tissue response parameter by a predetermined margin.

126. The method of claim 125, wherein detecting the infarcted tissue further comprises detecting the infarcted tissue when the tissue response parameter matches a template tissue response parameter within a predetermined margin.

127. The method of claim 125, further comprising repeating the delivering the drug, detecting the signal, and producing the tissue response parameter for a plurality of myocardial locations, wherein detecting the infarcted tissue comprises detecting the infarcted tissue based on the tissue response parameters produced for the plurality of myocardial locations.

128. The method of claim 127, wherein detecting the infarcted tissue comprises detecting an infarcted tissue region including one or more myocardial locations of the plurality of myocardial locations when the tissue response parameters for the myocardial locations adjacent to the one or more myocardial locations are substantially different from the tissue response parameters for the one or more myocardial locations.

129. The method of claim 122, wherein delivering the drug comprises delivering an agent changing contractility of myocardial tissue, wherein detecting the tissue response comprises sensing a signal indicative of the myocardial contractility, and wherein detecting the infarcted tissue comprises detecting the infarcted tissue based on the signal indicative of the myocardial contractility.

130. The method of claim 129, wherein delivering the drug comprises delivering isoproterenol.

131. The method of claim 129, wherein sensing the signal indicative of myocardial contractility comprises sensing an acceleration.

132. The method of claim 122, wherein delivering the drug comprises delivering nitroglycerin.

133. The method of claim 132, wherein detecting the tissue response comprises sensing a drug concentration.

134. The method of claim 133, wherein detecting the infarcted tissue comprises:

producing a rate of drug perfusion being a change in the sensed drug concentration over a predetermined period of time; and

detecting the infarcted tissue based on the rate of drug perfusion.