Patients with repaired Tetralogy of Fallot (ToF), who have RBBB and predominant right ventricular (RV) dysfunction may benefit from RV electromechanical resynchronization. We describe the case of a patient with repaired ToF, biventricular (BiV) dysfunction and ineffective cardiac resynchronization therapy (CRT) in whom His bundle pacing (HBP) fused with RV wall pacing achieved RV CRT and acute hemodynamic improvement. N/A 58 YOF with repaired ToF and BiV dysfunction presented with decompensated heart failure (HF). BiV implantable cardioverter-defibrillator (ICD) with RA, RV and coronary sinus (CS) leads (Biotronik, Berlin, Germany) was placed at an outside facility one year ago. Underlying EKG showed sinus rhythm with 1stdegree AVB (PR 240 ms), RBBB (QRSd 200ms) and left posterior fascicular block. With presenting CRT, QRS was wider (QRSd 240). Chest Xray revealed RV ICD lead in the right ventricular outflow tract (RVOT) and the CS lead in the anterior interventricular vein with the tip electrode also near RVOT. Given concern for suboptimal CRT, defibrillation vector and limited alternative options, we pursued individualized CRT optimization. Activation mapping showed latest RV activation in the basal lateral tricuspid annulus. Pacing from this site simultaneously with the His Bundle narrowed the QRS significantly and improved RVEF and dyssynchrony on intracardiac echocardiography. Fick cardiac output and index improved to 4.4 and 2.4 respectively from 3.7 and 2.0 at baseline. Thus, we removed the old CS lead and replaced the ICD lead with a new DF-1 defibrillator lead (Medtronic, Minneapolis, MN) in the RV apical septum. Then, we placed a SelectSecureTM His lead (3830 model, Medtronic, Minneapolis, MN). Non-selective His capture threshold was 1.0 V at 0.4 ms. Then, we placed a SelectSecureTM lead (3830 model, Medtronic, Minneapolis, MN) in the RV basal lateral wall and this was Y-adapted to a new LV lead (4196Y model, Medtronic, Minneapolis, MN) which was placed on a lateral branch of the CS. HBP fused with LV and RV lateral wall pacing resulted in a QRS of 120ms. At one year follow up, she has not had HF admissions. Simultaneous HBP and RV basal lateral wall pacing may be a feasible strategy for RV CRT in patients with ToF, RBBB and predominant RV dysfunction.