Inverse Electric Imaging of Myocardial Ischemia: Getting the Most by 72b3i16T

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									Electric Imaging of Myocardial
           Ischemia

    Rob MacLeod, Bonnie Punske,
   Shibaji Shome, Bulent Yilmaz, and
             Bruno Taccardi

   Cardiovascular Research and Training Institute
            Bioenginering Department
                University of Utah
                                               CVRTI
           Origins




                                 Occlusion
Pre-PTCA             Peak-PTCA




                                 CVRTI
Biophysics of Acute Ischemia



        0


        mV



        -80




                        CVRTI
Imaging Approach




                   CVRTI
     Cardiac Mapping of Ischemia
                LAD                             LCx


Epicardium




Endocardium




 Source of Electrocardiographic ST Changes in
 Subendocardial Ischemia
 Li et al. Circ. Res. 82:957-970, 1998
                                                      CVRTI
      Research Questions

• ST elevation or (transient) depression?
• Acute occlusion versus graded flow?
• How do ST changes image on the body
  surface?




                                      CVRTI
    Technical
    Apparatus


•   “Andy III”
•   370 electrodes
•   R = 500 W cm
•   Homogeneous
•   1024 channel
    acquisition



                     CVRTI
  Isolated Heart Preparation
Electrolytic
                          Flow Regulators
Torso Tank
       Heat Exchange
                                     C      J




                                      Support
                                       Dog
                       Epicardial Sock
                       Electrodes


                            TorsoTank
                            Electrodes




                                                CVRTI
Flow Control




               CVRTI
    Epicardial Electrode Sock
• Nylon stocking
  material
• 490 recording wires
• 24 pacing wires
• Reference markers
  for geometry




                           CVRTI
                Protocols
• Acute, complete occlusion
  – 3-minute duration
  – measurements each 30 s
• Graded flow
  – 2-minute intervals at each flow rate
  – measurement at end of each interval
• Graded heart rate
  – constant flow rate
  – increase rate in 2-minute intervals
  – measurement at end of each interval


                                           CVRTI
Signal Processing

         3/8          5/8

      80ms


Qon   Soff       SToff      Toff
               ST80




                            CVRTI
Tank/Heart Geometry




                      CVRTI
 Acute
Occlusion
  ST
 Flow    Time
30
         300
24       270
         240
         210
18
         180
         150
12
         120
          90
 6
          60
          30
0
ml/min    s
                4Jan01-ocl1   CVRTI
Graded
 Flow
 ST
30 ml/m

24 ml/m

18 ml/m

12 ml/m

 6 ml/m

 0 ml/m

          10Jan01-ocl1   CVRTI
Graded
Pacing
  ST80
(reduced flow)
34 ml/m          215

24 ml/m          190

18 ml/m          165

12 ml/m          150

 6 ml/m          130

 0 ml/m
          Flow   Heart Rate
                              10Jan01-ocl4   CVRTI
Fixed Rate, Decreased Flow

•   Start flow at 35
•   Reduce to 0
•   Increase back to 35
•   3 minutes at each flow rate




                                  CVRTI
Reduced
  Flow:
 ST-80
 Flow     Time
          33
35        30
          27
28        24
          21
21        18
          15
14        12
            9
 7          6
            3
 0
 ml/min     min
                  19Jan01-ocl1   CVRTI
Reduced
  Flow:
 ST-80
 Flow     Time
          33
35        30
          27
28        24
          21
21        18
          15
14        12
            9
 7          6
            3
 0
 ml/min     min
                  19Jan01-ocl1   CVRTI
Reduced
  Flow:
 ST-80
 Flow     Time
          33
35        30
          27
28        24
          21
21        18
          15
14        12
            9
 7          6
            3
 0
 ml/min     min
                  19Jan01-ocl1   CVRTI
Reduced
  Flow:
 ST-80
 Flow     Time
          33
35        30
          27
28        24
          21
21        18
          15
14        12
            9
 7          6
            3
 0
 ml/min     min
                  19Jan01-ocl1   CVRTI
Reduced
  Flow:
 ST-80
 Flow     Time
          33
35        30
          27
28        24
          21
21        18
          15
14        12
            9
 7          6
            3
 0
 ml/min     min
                  19Jan01-ocl1   CVRTI
Reduced
  Flow:
 ST-80
 Flow     Time
          33
35        30
          27
28        24
          21
21        18
          15
14        12
            9
 7          6
            3
 0
 ml/min     min
                  19Jan01-ocl1   CVRTI
Reduced
  Flow:
 ST-80
 Flow     Time
          33
35        30
          27
28        24
          21
21        18
          15
14        12
            9
 7          6
            3
 0
 ml/min     min
                  19Jan01-ocl1   CVRTI
Reduced
  Flow:
 ST-80
 Flow     Time
          33
35        30
          27
28        24
          21
21        18
          15
14        12
            9
 7          6
            3
 0
 ml/min     min
                  19Jan01-ocl1   CVRTI
Reduced
  Flow:
 ST-80
 Flow     Time
          33
35        30
          27
28        24
          21
21        18
          15
14        12
            9
 7          6
            3
 0
 ml/min     min
                  19Jan01-ocl1   CVRTI
Reduced
  Flow:
 ST-80
 Flow     Time
          33
35        30
          27
28        24
          21
21        18
          15
14        12
            9
 7          6
            3
 0
 ml/min     min
                  19Jan01-ocl1   CVRTI
Reduced
  Flow:
 ST-80
 Flow     Time
          33
35        30
          27
28        24
          21
21        18
          15
14        12
            9
 7          6
            3
 0
 ml/min     min
                  19Jan01-ocl1   CVRTI
Reduced
  Flow:
 ST-80
 Flow     Time
          33
35        30
          27
28        24
          21
21        18
          15
14        12
            9
 7          6
            3
 0
 ml/min     min
                  19Jan01-ocl1   CVRTI
 Fixed Flow, Increased Rate

• Start flow at 35
• Reduce to 21
• Increase rate




                         CVRTI
Increased Rate:
    ST-80
 Flow      Time       Rate

35        18         231

28        15         214
          12         200
21
           9         188
14
           6         176
 7         3         167
 0                   158
 ml/min        min         BPM
                                 19Jan01-ocl1   CVRTI
Increased Rate:
    ST-80
 Flow      Time       Rate

35        18         231

28        15         214
          12         200
21
           9         188
14
           6         176
 7         3         167
 0                   158
 ml/min        min         BPM
                                 19Jan01-ocl1   CVRTI
Increased Rate:
    ST-80
 Flow      Time       Rate

35        18         231

28        15         214
          12         200
21
           9         188
14
           6         176
 7         3         167
 0                   158
 ml/min        min         BPM
                                 19Jan01-ocl1   CVRTI
Increased Rate:
    ST-80
 Flow      Time       Rate

35        18         231

28        15         214
          12         200
21
           9         188
14
           6         176
 7         3         167
 0                   158
 ml/min        min         BPM
                                 19Jan01-ocl1   CVRTI
Increased Rate:
    ST-80
 Flow      Time       Rate

35        18         231

28        15         214
          12         200
21
           9         188
14
           6         176
 7         3         167
 0                   158
 ml/min        min         BPM
                                 19Jan01-ocl1   CVRTI
Increased Rate:
    ST-80
 Flow      Time       Rate

35        18         231

28        15         214
          12         200
21
           9         188
14
           6         176
 7         3         167
 0                   158
 ml/min        min         BPM
                                 19Jan01-ocl1   CVRTI
Increased Rate:
    ST-80
 Flow      Time       Rate

35        18         231

28        15         214
          12         200
21
           9         188
14
           6         176
 7         3         167
 0                   158
 ml/min        min         BPM
                                 19Jan01-ocl1   CVRTI

								
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