Cardiac resynchronisation therapy (CRT) is highly effective in dilated cardiomyopathy patients with impaired LVEF and LBBB. In cardiac amyloidosis (CA) patients, left ventricular dysfunction and conduction disorders are common but the potential benefit of CRT in this particular setting is unknown. We aimed to investigate outcomes of CA patients who were implanted of CRT devices with respect to left ventricular ejection fraction (LVEF) evolution and major cardiovascular events (MACE).

Our retrospective observational study included CA patients implanted with a CRT pacemaker (CRT-P) or defibrillator (CRT-D) from 2012 to 2019, in 8 French university hospitals. MACE were defined as either hospitalisation for heart failure or death at follow-up after CRT implantation.

We included 46 patients, [77 (±5) years old, 42 (91%) male sex]. Cardiac amyloidosis form was AL in 8 patients (17%) and senile/TTR in 38 (83%) patients. CRT indication was LBBB+LVEF<35% in 27 (59%) patients, upgrading for a LVEF drop after right ventricle pacing in 10 (22%) patients, RBBB+LVEF<35% in 6 (13%) patients and complete AV block (“Block HF” indication) in the remaining 3 (7%) patients. The implanted device was CRT-D in 19 patients (41%) and CRT-P in 27 patients (59%). At the time of CRT implantation, the mean LVEF was 31 (±8%). During a mean follow-up after CRT implantation of 620 days, 31 (67%) MACE occurred. After Cox multivariate analysis, the only predictor of MACE was NYHA>2 at the time of CRT implantation [OR: 2.18 (1.03–4.60); P=0.059]. We tested the clinical impact of CRT response with various definitions (10/20/25%) validated in the literature but none was significantly associated with MACE.

In cardiac amyloidosis patients implanted with a CRT device, the one-year echocardiographic response is not significantly associated with a reduction of MACE at long-term follow up. Thus, the benefit of CRT in CA patients appears uncertain.