Newly acquired complete right bundle branch block early after heart transplantation is associated with lower survival.

Aims: Right bundle branch block (RBBB) after heart transplantation (HTX) is a common finding, but its impact on post-transplant survival remains uncertain. This study investigated the post-transplant outcomes of patients with complete RBBB (cRBBB) ≤ 30 days after HTX.

Methods: This registry study analysed 639 patients receiving HTX at Heidelberg Heart Center between 1989 and 2019. Patients were stratified by diagnosis of cRBBB ≤ 30 days after HTX. Analysis included recipient and donor data, medication, echocardiographic features, graft rejections, atrial fibrillation, heart rates, permanent pacemaker implantation and mortality after HTX including causes of death.

Results: One hundred thirty-nine patients showed cRBBB ≤ 30 days after HTX (21.8%), 20 patients with pre-existing cRBBB in the donor heart (3.2%) and 119 patients with newly acquired cRBBB (18.6%). Patients with newly acquired cRBBB had a worse 1-year post-transplant survival (36.1%, P < 0.01) compared with patients with pre-existing cRBBB (85.0%) or without cRBBB (86.4%), along with a higher percentage of death due to graft failure (P < 0.01). Multivariate analysis indicated cRBBB ≤ 30 days after HTX as significant risk factor for 1-year mortality after HTX (HR: 2.20; 95% CI: 1.68-2.87; P < 0.01). Secondary outcomes showed a higher rate of an enlarged right atrium (P = 0.01), enlarged right ventricle (P < 0.01), reduced right ventricular function (P < 0.01), 30-day atrial fibrillation (P < 0.01) and 1-year permanent pacemaker implantation (P = 0.02) in patients with cRBBB after HTX.

Conclusions: Newly acquired cRBBB early after HTX is associated with increased post-transplant mortality.