Left atrial dual-loop reentry with endocardial and epicardial conduction pathway

Dual-loop reentry is a commonly iatrogenic atrial arrhythmia often caused by previous open-heart surgery.1–4 The reentry circuits primarily involve incisional wounds created for cardiopulmonary circulation support or to access the target sites within the heart, as well as the tricuspid annulus. Entrainment mapping is a fundamental maneuver for identifying reentry circuits in electrophysiological studies; recent advances in high-density mapping technology have further facilitated this process.5