Applied topology to treat cardiac arrhythmia

This is me

Robin

Professor Nele Vandersickel

Sander Hendrickx

  • Physics and astronomy at Ghent University
  • Masterthesis at biophysics
  • 3rd year PhD at biophysics
    • Topology on cardiac arrhythmia
    • Developing software package: openDGM

Overview

  • Clinical validation
  • Conclusion
  • Future research
  • Cardiac arrhythmia
    • Electrical waves
    • Mechanisms
    • Atrial tachycardia
  • Topology
    • Deformation
    • Index theorem
  • Simulations
    • Patterns
    • Virtual treatment

What is an arrhythmia

Any abnormal heartbeat, disturbing the normal rhythm

 

  1. Anatomy
    • Atria / ventricles
    • Left / right
  2. ECG
    • Regular
      • Faster: tachycardia
      • Slower: bradycardia
    • Irregular
      • Fibrillation

Electrical waves in the heart

Complex system of differential equations

Action potential

Arrhythmia mechanisms

3 main mechanisms for maintaining arrhythmia

Focal beats

Anatomical reentry

Functional reentry

Clinical: the atrial tachycardia

Atrial tachycardia (AT):

Atria, Regular, Fast

 

Mechanism: Anatomical reentry

 

Treatment: Ablation procedure (burning tissue)

 

Standard practice:

  1. Electro-anatomical map
  2. Identify the reentrant boundary
  3. Ablate to the closest non-conductive structure

 

Problem:

A slower AT can arise after ablation

Topology in cardiac arrhythmia

  • Field of mathematics
  • Deformation
  • Preservation of properties

LPV

MV

RPV

LPV

MV

RPV

Topology: the index theorem

  • Calculation of Index / Topological charge
    • 0 for no rotation
    • +1 for counter-clockwise rotation
    • -1 for clockwise rotation

 

  • Closed surface
  • Sum of all TC = 0

 

  • Consider tachycardia:
    • Only anatomical reentry
    • Pairs of counter rotating patterns

Simulations

Complete rotation

Near-complete rotation

Parallel activation

TC = +1

TC = -1

TC = 0

Simulations: ablation

Clinical validation

  • Clinical proof of concept: 24 cases
  • 131 High Quality clinical cases
  • Upcoming multi-center clinical study
  • Upcoming dataset of bi-atrial tachycardia

Dr. M. Duytschaever

Dr. A. Luik

Dr. S. Knecht

A. Haas

Conclusion

1. Rotational patterns in atrial tachycardia exist in counter-rotating pairs.

 

2. Only ablation between the rotation pairs will terminate the tachycardia. Any other ablation will either cause no notable change or slow down the tachycardia.

Future research

  • Bi-atrial
    • More complex topology
    • Voids

 

  • Atrial fibrillation
    • Functional reentry
    • Mathematical boundaries (singularities)

 

  • Ventricles: thickness
    • 2D manifolds

Thank you!

Questions?

Appendix: index calculation