Background: Cardiac amyloidosis (CA), particularly transthyretin-related (ATTR-CA), frequently causes conduction disease requiring pacing. Conventional right ventricular pacing (RVP) may worsen heart failure (HF) through dyssynchronous activation, while left bundle branch area pacing (LBBAP) provides a more physiological alternative. Comparative data in CA are lacking.
Methods: This single-center, retrospective study included CA patients with CIED (cardiac implantable electronic devices with LBBAP and RVP. It aimed to compare feasibility, procedural characteristics, and outcomes between both approaches. Diagnosis of CA followed current guideline criteria. HF worsening was defined as clinical deterioration requiring escalation of diuretics or outpatient reassessment; acute HF events as hospitalizations for decompensated HF.
Results: 35 CA patients (22 LBBAP, 13 RVP) were included. Overall, 32 (91%) had transthyretin cardiac amyloidosis (ATTR-CA) and 3 (9%) light-chain amyloidosis (AL-CA). Baseline HF was more advanced in the LBBAP group (NYHA 2.6 ± 0.7 vs 2.0 ± 0.6, p = 0.007; BNP 594 ± 617 vs 121 ± 71 pg/mL, p = 0.006). Procedural and fluoroscopy times were longer with LBBAP, but paced QRS duration was significantly shorter (116 ± 17 vs 159 ± 12 ms, p < 0.001). During follow-up (16 ± 10 vs 32 ± 24 months), LBBAP was associated with markedly fewer HF worsening (9.1% vs 69.2%, p = 0.0012) and acute HF events (4.5% vs 69.2%, p < 0.001), despite higher ventricular pacing burden (>40% in 90.9% vs 53.8%, p = 0.032). Mortality (22.7% vs 15.4%, p = 0.689) and complication rates (9.1% vs 15.4%, p = 0.618) were comparable.
Conclusions: LBBAP is feasible and safe in cardiac amyloidosis and may prevent HF progression compared with RVP, even in advanced disease. These findings support LBBAP as a preferred pacing strategy in CA, warranting validation in larger prospective studies
