Upper Loop Reentry Revisited: Clinical Features, Mechanisms, and Therapeutic Approaches-Insights From a Case Series

Area of Science:

• Cardiology
• Electrophysiology
• Cardiac Arrhythmias

Background:

• Upper loop reentry (ULR) is a macroreentrant atrial flutter.
• ULR is associated with cardiac surgeries and atrial fibrillation ablation.
• Clinical features and ablation strategies for ULR are not well-defined.

Purpose of the Study:

• To describe the clinical features of ULR.
• To evaluate individualized catheter ablation strategies for ULR.

Main Methods:

• Retrospective analysis of six ULR cases treated with catheter ablation.
• Individualized ablation strategies based on identified slow conduction zones (SCZs) or anatomical substrates.

Main Results:

• ULR occurred post-cardiac surgery, transseptal procedures, and atrial fibrillation ablation.
• SCZs were variably located; one case lacked a distinct SCZ.
• All patients achieved successful tachycardia termination with no inducible arrhythmia.

Conclusions:

• ULR circuits are heterogeneous and occur in diverse clinical settings.
• Individualized ablation strategies are effective for ULR elimination.