Key result
Catheter ablation successfully terminates rare intra-CTI macro-reentrant atrial tachycardia after prior cardiac surgery.
Why the study?
Intra-isthmus reentry has been reported as an atypical atrial tachycardia, but a distinct macro-reentrant form localized within the cavotricuspid isthmus region in a post-cardiac surgery patient had not been previously described.
Case Report (n=1)
No
Demonstrates a new form of macro-reentrant intra-isthmus reentry localized entirely within the cavotricuspid isthmus, successfully mapped and treated with linear ablation.
Linear ablation terminated novel intra-isthmus reentry; extends circuit mapping but leaves open validation in larger cohorts.
Background Intra-isthmus reentry, in which the tachycardia circuit is localized within the cavotricuspid isthmus region and the coronary sinus ostium, has been reported as an atypical form of atrial tachycardia. It has been delineated by three-dimensional mapping as either macro-reentrant type around the cavotricuspid isthmus and coronary sinus area (but with the coexistence of typical atrial flutter), or focal type from the cavotricuspid isthmus area. Case summary We present the first reported case of an apparently new form of macro-reentrant intra-isthmus reentry that occurred in a patient with history of prior cardiac surgery. By correcting incorrect annotation of double potentials at the cavotricuspid isthmus lesion, the local activation time map showed a reentrant circuit rotating around a low-voltage area within the cavotricuspid isthmus region. Preoperative computed tomography revealed a pouch on the septal side of the cavotricuspid isthmus that was anatomically adjacent to the boundary of the tachycardia circuit. Termination of tachycardia was achieved by typical cavotricuspid isthmus linear ablation. Discussion The formation of a low-voltage area, which might have been created by prior surgery, was presumed to contribute to the maintenance of intra-isthmus reentry as a kind of boundary. By use of an ultra-high-resolution mapping system and the entrainment pacing maneuver, we could clearly delineate the tachycardia circuit and determine an ablation strategy.
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Miyake et al. (2026) conducted a case report in Intra-cavotricuspid isthmus reentrant atrial tachycardia (n=1). Catheter ablation was evaluated on Termination of tachycardia. Catheter ablation successfully terminated a rare form of intra-cavotricuspid isthmus macro-reentrant atrial tachycardia in a patient with prior cardiac surgery.
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