109-04: Triple-site pacing cardiac resynchronization therapy in patients with permanent atrial fibrillation: results from a prospective observational study

Abstract

Purpose: cardiac resynchronization therapy (CRT) still has a significant non-response rate of 30%. In patients with atrial fibrillation (AF) the rate of non-responders is even higher, and few studies focused on this specific subgroup of patients. Triple-site pacing (Tri-V) is a new method of CRT which may help overcome these limitations. We aim to assess the effectiveness of this new type of CRT in patients with permanent AF. Methods: single-center prospective observational study of patients with permanent AF, NYHA class ≥ II and ejection fraction < 35% who underwent CRT implantion. 2 leads were implanted in the right ventricle, one in the apex and another in the outflow tract septal wall. A left ventricle lead was implanted as usual in a conventional CRT. Within 1 month after implantation, all patients underwent minimally invasive hemodynamic assessment using the Vigileo Flotrac® (Edwards Lifesciences) for the determination of cardiac output in Tri-V or conventional biventricular pacing (Bi-V). The final mode (Tri-V vs Bi-V) was programmed according to the hemodynamic performance. Patients follow-up (FUP) was then undertaken at 6 and 12 months, and included clinical assessment with NYHA class determination, quality of life (Qol) assessment with the Minesota QoL questionaire, 6-minute walk test (6MWT) and echocardiogram with determination of the ejection fraction (EF). Patients were classified as responders if NYHA class was reduced by at least one level and EF increase of ≥ 10%, and as super-responders if NYHA class at FUP was I and EF ≥ 50%. Survival rates and survival free of heart failure hospitalization were calculated. For statistical analysis we used the paired samples T test. Summary of Results: we included 40 patients (93% male, mean age 72 ± 10 years). 32 (80%) were programmed in Tri-V based on the hemodynamic test results. The following results pertain to this subgroup. At baseline, 58% of pts were in NYHA class III and 42% NYHA class II, with a mean ejection fraction of 28% ± 5. After completion of 1 year of follow-up, mean QoL score more than halved (31 ± 21 vs. 15 ± 18; p = 0,017 at 12 months), the 6MWT distance was significantly improved in the responder group (416 ± 104 m to 465 ± 107 m, p = 0,005 at 12 months) and the mean ejection fraction also increased (28 ± 5 vs. 40 ± 10; p < 0,001 at 6 months and 28 ± 5 vs. 41 ± 10; p < 0,001 at 12 months). The responder rate was 62% at 6 months and 76% at 12 months. The super-responder rate was 9% at 6 months and 25% at 12 months. 4 pts died. Survival free of of heart failure hospitalization was 87,5%. Conclusion: Tri-V CRT yielded a high response rate, and a much higher super-response rate, than usually reported for conventional CRT in patients with permanent AF. There was a clear improvement in functional capacity and QoL, as well as positive reverse remodeling. These results may warrant considering Tri-V as a first line therapy in patients with permanent AF who are candidates for CRT, or as an upgrade option in non-responders.