Exploring the cause of conduction delays in patients with repaired Tetralogy of Fallot

Abstract Aims Cardiac dyssynchrony in patients with repaired Tetralogy of Fallot (rToF) has been attributed to right bundle branch block (RBBB), fibrosis and/or the patches that are inserted during repair surgery. We aimed investigate basis abnormal activation rToF by mapping electrical sequence sinus rhythm (SR) and ventricular (RV) pacing. Methods Results A total 17 were studied [13 rToF, 2 left (LBBB), without RBBB or LBBB (non-BBB)] medically indicated cardiac During SR RV pacing, measurements performed using 112-electrode endocardial balloons (rToF only) biventricular epicardial sock arrays (four all non-rToF patients). SR, functional lines occurred five patients, while pacing caused blocks four patients. The line persisted both only out 13 Compared increased dispersion septal activation, but not free wall. comparable Conclusion results present study indicate delayed ventricle is predominantly due block(s) Purkinje system conduction tissue fairly normal.