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

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

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