Abstract
BACKGROUND: There is currently no evidence of the best pacing mode for high-degree atrioventricular (AV) block occurring after transcatheter aortic valve implant (TAVI) in patients with preserved left ventricular systolic ejection fraction (LVEF). PURPOSE: The purpose of the trial was to compare a clinical combined endpoint achieved by left bundle branch pacing (LBBP) vs right ventricular (RV) pacing in patients with preserved LVEF post-TAVI at 12-month follow-up. METHODS: Physiological vs right ventricular pacing in patients with normal ventricular function post-TAVI (Phys-TAVI) was a pilot study designed as a single-center, prospective, randomized, parallel-controlled clinical trial. Adhered to CONSORT guidelines. Consecutive patients (n=24) post-TAVI with high-degree AV block and LVEF≥50% were randomized to LBBP or RV pacing. The primary endpoint was survival with an improvement ≥1point in NYHA class or ≥25% increase in the distance covered in the 6-minute-walking-test (6MWT). Secondary endpoints were change in LVEF, septal flash correction, mitral regurgitation, NTproBNP, heart failure hospitalization, score on symptoms (KCCQ-12 Kansas City Cardiomyopathy Questionnaire), and QRS duration. RESULTS: Twenty-four patients were included, 12 in each arm. Median stimulation 98.6% (75%-99%), no differences between groups. Both groups showed a similar incidence of the primary endpoint: 33.3% (n=4) in LBBP group vs 25% (n=3) in RV group (p=1). One patient in each group had died at 1-year follow-up. In relation to secondary endpoints, significant shortening in the QRS was observed in LBBP patients, as compared to RV pacing (median -39ms vs 0ms), p<0.001. Septal flash excursion was significantly lower for the LBBP group (median 0mm vs 2mm), p=0.03. None of the patients had LVEF<50% at 12-month follow-up. CONCLUSION: Similar midterm outcomes were obtained with LBBP and RV pacing in an elderly population with high-degree AV block and preserved LVEF after TAVI. The pilot Phys-TAVI trial showed the feasibility of LBBP in this population and set paves the way for larger randomized clinical trials with extended follow-up to test for differential clinical outcomes between pacing modalities. [Figure: see text] [Figure: see text]