Transcript Heart Electrical Activation

HEART ELECTRICAL ACTIVATION
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By: Elnaz Shokrollahi
Supervisors: Dr. S. Krishnan
Dr. K. Nanthakumar
SIGNAL PROPAGATION IN HEART
1.
Stimulus originates in the SA
node and travels across the
walls of the atria, causing
them to contract.
2.
Stimulus arrives at the AV
node and travels along the AV
bundle
3.
Stimulus descends to the apex
of the heart through the
bundle branches
4.
After stimulus reaches the
Purkinje fibers, the ventricles
contract.
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CARDIAC ARRHYTHMIA

Cardiac arrhythmia is when the electrical activity of the
heart is irregular (faster/slower) than normal.
Tachycardia
(Fast Heartbeat)
Bradycardia
(Slow Heartbeat)
Ventricular Fibrillation
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CARDIAC ELECTROPHYSIOLOGY (EP)
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CONVENTIONAL EP MAPPING
 Point-by-point
mapping acquisition.
 Direct voltage mapping.
 Many Disadvantages:



Identification of areas of low voltage is timeconsuming catheter manipulation.
Focal lesion creation may not be sufficient to ablate
VT conduction through a broad isthmus region.
Identification breakthrough points may be
challenging.
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NON-CONTACT MAPPING
 Catheter
of its own.
 Non-contact
mapping
uses unipolar Virtual
Electrograms (VE)
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ILLUSTRATION OF GEOMETRY AND
POSITION OF PACED AREAS
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ELECTROGRAM
o Recording of cardiac potentials
from electrodes directly in contact
with the heart.
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TIME-DOMAIN ANALYSIS


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-Peak Negative Voltage (PNV) in (mV)
-Maximal Negative dV/dt (mV/ms)
-Area Under the Curve (AUC)
-Presence of an initial R-wave
-Duration
-Presence of low-amplitude depolarization
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RESULTS OF TIME-DOMAIN ANALYSIS
Case
Endocardial
Epicardial
Latency
14.5 ± 5.3 ms
18.2 ± 7.8 ms
Duration
18.8 ± 6.2 ms
22.2 ± 5.3 ms
PNV
-2 ± 1 mV
-3 ± 5.3 ms
Low Amp. Depo
0%
60%
Max Neg dV/dt
1.6 ± 0.2mV/ms
2.27 ± 0.4mV/ms
AUC
881 ± 36
1090 ± 50.5
R-wave
0%
80%
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FREQUENCY- DOMAIN ANALYSIS

FFT requires large quantities of data to produce
significant result.
X ( k )   x ( j )
N
( j  1)( k  1)
N
j 1

AR modeling
i p
xn    ai xn i   n
i 1
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RESULTS OF CLASSIFICATION
Results with AR Coefficients
Method
Groups
Endocardial
Epicardial
Total
Original
Endocardial
Epicardial
Endocardial
Epicardial
Endocardial
Epicardial
Endocardial
Epicardial
44
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97.8
15
42
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93.3
18.3
1
51
2.2
85
3
49
6.7
81.7
45
60
100
100
45
60
100
100
%
Cross-Validated
%
CONCLUSIONS

Presented electrographic parameters.

Morphologies of electrograms allowed the
discrimination of endo/epicardially paced activation.
Possibility of combination of the criteria will
improve the perception over any single criterion.
 Allow to detect tachycardia originating
epicardially using noncontact mapping.

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BRAIN STORMING
Thank you for
your attention!
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