Abstract 3381: Further Reverse Ventricular Remodeling by Dual-site Left Ventricular Pacing in Cardiac Resynchronization Therapy
Cardiac Resynchronization Therapy (CRT) is usually achieved by pacing the two ventricles at one site each. Current evidence indicates standard biventricular pacing (SBVP) may fail at providing acceptable mechanical ventricular resynchronization (VR) in a large subset of CRT patients, especially those with very enlarged heart. We hypothesised triple-site biventricular pacing (TSVP) with 2 LV leads, would further improve VR and reverse ventricular remodeling as compared to SBVP. The TRIP-HF (triple-site biventricular pacing in heart failure) study was a single blind randomised crossover comparison of the clinical and mechanistic effects of TSVP versus SBVP during two periods of 3-month each. Inclusion criteria were NYHA class III-IV chronic heart failure, optimal medical treatment, permanent atrial fibrillation with slow ventricular rate (to ensure permanent and complete ventricular capture with pacing) and LVEF≤35%. Patients were implanted with a CRT device connected to 3 ventricular leads, 2 LV leads (LV1 and LV2) placed in opposite position and 1 RV lead. LV1 and LV2+RV were connected to the atrial and ventricular ports, respectively. TSVP and SBVP were achieved by programming the device in the DDDR and VVIR modes, respectively. The primary endpoint of the study was the absolute change in VR compared to baseline. The principal second endpoint was reverse ventricular remodeling. 40 pts, mean age: 70±9 yrs, NYHA III/IV: 85%/15%, LVEF: 26±11%, intrinsic QRS width:165±42 ms, were included. 34 pts (85%) were successfully implanted (3 leads). 26 pts completed the follow-up and are included in the “per-protocol” analysis. TSVP lead to a wider mean QRS: 171±20 ms vs. 155 ±25 ms (p=0.0112), a higher increase in LVEF: 35±13 vs. 27±11% (p=0.001) and to a smaller LVESV: 134±75ml vs. 157±69ml (p=0.0191). No significant differences were observed in Z-ratio, 6 minWT, QOL score, LV ESD, inter and intra ventricular mechanical delays and mitral regurgitation area. Conclusion: Chronic TSVP is technically feasible. A significant improvement in LVEF was observed with TSVP, but without detectable benefit in clinical status during the 3 months follow-up time. Further and larger clinical studies are needed to evaluate the real clinical relevance of this new CRT modality.