Alternating Right and Left Bundle Branch Block: Management in a Patient with Cardiac Amyloidosis.

Alternating bundle branch block (ABBB) is a phenomenon described by the presence of both right bundle branch block (RBBB) and left bundle branch block (LBBB) in the same individual at different points in time. We present the case of a 74-year-old male with known cardiac amyloid who was managed in hospital for an ABBB in the context of an accidental fall. Serial electrocardiograms (ECGs) revealed transient alternating RBBB and LBBB. The patient underwent dual-chamber permanent pacemaker implantation. This case reviews the management of alternating bundle brunch blocks and highlights the complexities of treating conduction disease in patients with cardiac amyloid.