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Posteroseptal RVOT PVCs in a Clockwise-Rotated Congenital Heart: A Left-Sided Illusion
Adithya Shastry1, Lung En Teng1, Robert D Anderson1
1Department of Cardiology, The Royal Melbourne Hospital, Melbourne, Victoria, Australia.
Background:
Electrocardiography (ECG) localization of ventricular arrhythmias assumes normal cardiac anatomy. In cases of adult congenital heart disease, surgical remodeling can confound traditional algorithms.
Case:
A 26-year-old male with repaired pulmonary atresia and ventricular septal defect presented with a 17% premature ventricular complexes burden. The ECG showed right bundle branch block morphology, inferior axis, and positive precordial concordance, classically suggesting a left-sided origin. However, cardiac computed tomography revealed extreme clockwise rotation, displacing the right ventricular outflow tract (RVOT) posteriorly.
Management:
Guided by imaging, mapping prioritized the RVOT. Earliest activation (-20 ms) and a 99% pace-map match were identified at the posteroseptal RVOT. Ablation resulted in immediate suppression, confirming the right-sided origin.
Conclusions:
This "left-sided illusion" demonstrates that anatomical rotation can cause right-sided foci to mimic left-sided origins. Integrating cross-sectional imaging with ECG interpretation is critical for guiding ablation strategies in the adult congenital heart disease population.
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