HEART ELECTRICAL ACTIVATION

By: Elnaz Shokrollahi

Supervisors: Dr. S. Krishnan

Dr. K. Nanthakumar

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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.

Ventricular Fibrillation Tachycardia

(Fast Heartbeat)Bradycardia

(Slow Heartbeat)

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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 time-consuming 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

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o Recording of cardiac potentialsfrom electrodes directly in contactwith the heart.

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

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.

AR modeling

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( 1)( 1)

1

( ) ( )N

j kN

j

X k x j

1

i p

n i n i ni

x a x

RESULTS OF CLASSIFICATION

Method Groups Endocardial Epicardial Total

Original Endocardial 44 1 45Epicardial 9 51 60

% Endocardial 97.8 2.2 100Epicardial 15 85 100

Cross-Validated Endocardial 42 3 45Epicardial 11 49 60

% Endocardial 93.3 6.7 100Epicardial 18.3 81.7 100

Results with AR Coefficients

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 STORMINGThank you for your attention!

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