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A New Mechanistic Insight Into Macro-Reentrant Atrial Tachycardia in a Patient With Modified Fontan Circulation.
Peter C Murray1, Intisar Ahmed1, Krishnakumar Nair1
1Toronto General Hospital University Health Network Toronto Ontario Canada.
Journal of Arrhythmia
|April 13, 2026
Summary
Fontan flutter, an unusual atrial tachycardia, was identified in a patient with an atrio-pulmonary connection conduit. Radiofrequency ablation successfully terminated the tachycardia by targeting the circuit around the conduit base.
Area of Science:
- Cardiology
- Electrophysiology
- Congenital Heart Disease
Background:
- The Fontan procedure is a palliative surgery for single-ventricle defects, creating an atrio-pulmonary connection (APC) conduit.
- Atrial tachycardia is a known complication after Fontan surgery, but specific circuit mechanisms can be complex.
Purpose of the Study:
- To describe an unusual case of atrial tachycardia in a patient with an APC conduit.
- To elucidate the tachycardia circuit mechanism and demonstrate successful ablation.
Main Methods:
- Case report detailing electrophysiological study in a patient with Fontan physiology.
- Mapping of atrial tachycardia circuit propagation around the APC conduit.
- Radiofrequency ablation targeting the identified circuit.
Main Results:
- An unusual atrial tachycardia circuit was identified, propagating around the base of the APC conduit.
- Radiofrequency ablation delivered at a specific point (green arrow) successfully terminated the tachycardia.
- The findings illustrate a unique mechanism of arrhythmia in Fontan patients.
Conclusions:
- Fontan flutter can represent an unusual atrial tachycardia circuit around an APC conduit.
- Targeted radiofrequency ablation is effective for terminating such arrhythmias.
- Understanding these specific circuits is crucial for managing arrhythmias in Fontan survivors.
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