301 Clinical Outcome and Echographic Features of Patients with Repaired Tetralogy of Fallot and Biventricular Pacing

Right heart failure is a common feature in patients with repaired tetralogy of Fallot (TOF), right ventricular (RV) dysfunction and right bundle branch block (RBBB). Biventricular pacing (BVP) has been described as a potentially useful therapeutic in some cases. We aimed to investigate the clinical outcome and dyssynchrony echocardiographic characteristics of patients with repaired TOF and BVP. A systematic retrospective study of all of the patients of CHU de Bordeaux with repaired TOF and BVP was realized. Clinical NYHA status and exercise test performance were retrieved before and 6 months after BVP. All patients benefited from an echocardiography with dyssynchrony measures in spontaneous rhythm, RV pacing and BVP. 10 patients (7 male, 36,6 ± 13 years old) were retrieved from our database. Surgical repair had occurred at the age of 7,4 ± 5,8 years. BVP was effective since 18 ± 10 months. After 6 months of BVP were noted a significant improvement in NYHA class (1,3 ± 0,4 vs 1,8 ± 0.6, p = 0.05) and exercise test capacity (93 ± 22 W vs 78 ± 14 W, p<0,05). In spontaneous rhythm (SR), a significant inter-ventricular dyssynchrony was found (41 ± 13 ms, p<0,01) as well as late activation of RV lateral wall (electrosystolic delay: 42 ± 22 ms vs lateral LV wall and 49 ± 30 ms vs interventricular septum; p<0,01 for both). This dyssynchrony is corrected in biventricular pacing (inter-ventricular delay 8,6 ± 6,4 ms electrosystolic delays repectively 25,5 ± 13 ms and 12 ± 9 ms, p<0,01 vs SR). RV pacing is responsible for late activation of LV lateral wall (36,5 ± 30 ms) BVP pacing in selected patients with repaired TOF, BVP significantly improves dyssynchrony parameters. This is associated with significative improvement of clinical status.