Upgrade of cardiac resynchronization therapy by utilizing additional His-bundle pacing in a patient with lamine A/C cardiomyopathy: an autopsy case report

Background A number of heart failure patients (HF) do not fully benefit from cardiac resynchronization therapy (CRT). Although His bundle pacing (HBP) have been developed as an alternative strategy, its role for treating advanced cardiomyopathy remains unclear. Case summary We previously reported a patient with lamin A/C cardiomyopathy (Eur Heart J Case Rep. 2020; 4:1-9). He had turned non-response to conventional biventricular pacing (BVP), and an upgrade to CRT combining para-His bundle pacing (HBP) and left ventricular (LV) pacing had markedly improved his HF status. In the present report, we assessed the autopsy and histological findings of this patient. A histological examination of both the LV and right ventricular (RV) apex pacing regions exhibited extensive scarring. Although a distinct conduction system was not identified in the alternative para-HBP region, the RV endocardium had more viable myocytes in this region. Discussion In patients with advanced cardiomyopathy accompanied by extensive fibrosis, RV apex pacing, delivered from scar tissue, can render conventional BVP ineffective. Additionally, HBP alone can not provide adequate resynchronization under the presence of diffuse injury of the His-Purkinje system. In these circumstances, combined para-HB and LV pacing may facilitate electrical and mechanical resynchronization of the ventricles and may be attributed to favourable CRT response in advanced HF, even if para-HBP fails to directly capture the conduction system.