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IART in Repaired CHD — EECC MCQ

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ModerateCongenital Heart Disease (Adult)IART in Repaired CHDEECC

A 25-year-old man with repaired tetralogy of Fallot develops atrial flutter. His cardiologist notes this is a common late complication. What type of atrial flutter is most common in repaired congenital heart disease?

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Correct answer: C — Incisional (intra-atrial) re-entrant tachycardia (IART) — macro-re-entrant circuits around surgical scars and atriotomy sites rather than the typical CTI-dependent flutter; these atypical circuits require detailed electroanatomical mapping for successful ablation

Atrial arrhythmias are the most common late complication in adults with repaired CHD (ACHD), occurring in 10-50% depending on the type of repair. The predominant arrhythmia is NOT typical CTI-dependent flutter but rather intra-atrial re-entrant tachycardia (IART), also called incisional or atypical flutter. IART circuits form around: (1) surgical atriotomy scars (from the right atriotomy used for VSD/ASD closure, Fontan baffles, etc.); (2) prosthetic patches/baffles; (3) natural barriers (crista terminalis, IVC/SVC orifices). These circuits are often complex and multiple. The 2020 ESC ACHD Guidelines recommend: (1) catheter ablation at experienced ACHD electrophysiology centres with 3D electroanatomical mapping (CARTO/EnSite); (2) success rates are lower than for typical flutter (~60-80% vs >95%) with higher recurrence rates (different circuits may develop); (3) anticoagulation for all ACHD patients with atrial arrhythmias.

Reference: ESC (2020): ACHD Guidelines