Rapid detection of isthmus block and rhythm change using local electrogram changes during complex atrial flutter...

Area of Science:

• Electrophysiology
• Cardiac Arrhythmia Research
• Catheter Ablation Techniques

Background:

• Multiple re-entry circuits can coexist in the atria, complicating ablation procedures.
• Ablating one circuit may lead to unnoticed transitions to other rhythms due to seamless changes in surface electrocardiogram and tachycardia cycle length.

Purpose of the Study:

• To develop and illustrate methods for rapid identification of rhythm transitions and isthmus block during ablation.
• To highlight the importance of local electrogram analysis in managing complex atrial re-entry.

Main Methods:

• Analysis of local electrogram changes at the ablation site.
• Observation of rhythm transitions in three patient cases undergoing ablation for multiloop re-entry tachycardias.

Main Results:

• Local activation sequence changes, electrogram timing, and pre-existing double potentials effectively indicated isthmus block.
• Prompt detection of rhythm transitions was achieved using these electrogram-based methods.

Conclusions:

• Local electrogram analysis is crucial for promptly identifying isthmus block during ablation of coexisting atrial re-entry circuits.
• This approach helps prevent unnoticed rhythm transitions and ensures effective ablation outcomes.