Characteristics of Scar-Related Ventricular Tachycardia Circuits Using Ultra-High-Density Mapping: A Multi-Center
Ruairidh Martin1,2, Philippe Maury3, Caterina Bisceglia4
1LIRYC Institute/INSERM 1045, Bordeaux University Hospital (R.M., C.D., C.A.M., M.T., A.F., N.T., T.K., K.V., M.W., G.C., J.D., G.M., T.P., A.D., N.D., M. Hocini, M. Haïssaguerre, P.J., R.D., F.S.).
Circulation. Arrhythmia and Electrophysiology
|October 26, 2018
Summary
Ultra-high-density mapping revealed complex ventricular tachycardia (VT) circuits in structural heart disease. Barriers to conduction, including slow electrical activity, define VT isthmuses, impacting ablation strategies.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Imaging
Background:
- Ventricular tachycardia (VT) in structural heart disease relies on reentry within scar tissue.
- Detailed assessment of VT circuits has been limited by mapping resolution.
Purpose of the Study:
- To utilize ultra-high-density mapping for a more detailed assessment of ventricular tachycardia circuits.
- To analyze the topography, conduction velocity, and voltage of VT circuits.
Main Methods:
- Analysis of ultra-high-density mapping data from VT ablation cases across 6 European centers.
- Offline map analysis to generate activation maps of tachycardia circuits.
- Evaluation of circuit complexity, barriers, conduction velocity, and local voltage.
Main Results:
- Thirty-six tachycardias in 31 patients were analyzed, revealing complex VT circuits (11 single-loop, 25 double-loop).
- Isthmuses were defined by anatomic obstacles, block, and slow conduction in 75% of cases.
- Conduction velocity varied significantly within the circuit, being slowest at entrances and exits compared to the mid-isthmus.
Conclusions:
- VT circuits are complex, featuring multiple entrances, exits, and dead ends.
- Conduction barriers within the isthmus are partly functional, with slowed conduction at entrances/exits.
- Isthmus voltage during VT can be higher than during sinus or paced rhythms, suggesting altered tissue properties.
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