Signature signal strategy: Electrogram-based ventricular tachycardia mapping.

Area of Science:

• Cardiovascular Electrophysiology
• Cardiac Arrhythmia Research

Background:

• Ventricular tachycardia (VT) substrate is complex, involving slow conduction, unidirectional block, and exit sites within ventricular scars.
• Current VT ablation often targets abnormal electrograms without fully appreciating their specific signatures during different cardiac rhythms.

Purpose of the Study:

• To promote physiology-based VT mapping and targeted ablation by focusing on underappreciated aspects of ischemic scar-related VT circuits.
• To provide practical applications for VT ablation procedures by analyzing characteristic electrograms.

Main Methods:

• Exploration of anatomic and functional elements underlying distinctive bipolar electrograms in VT substrates.
• Analysis of tissue branching, conduction restitution, and wave curvature in relation to VT initiation and maintenance.

Main Results:

• Identification of three critical components of re-entrant VT circuits within ventricular scars: slow conduction regions, unidirectional block zones, and exit sites.
• Characterization of distinct electrograms associated with these components during sinus rhythm, VT initiation, and sustained VT.

Conclusions:

• A proposed VT ablation approach based on recognizing signature electrogram features can improve targeting of critical VT circuit elements.
• Understanding these electrophysiological hallmarks is essential for effective scar-related VT ablation.