Abstract
BACKGROUND: Relatively little is known about the clinical features of left bundle branch block (LBBB) in patients previously treated with chest radiation therapy (RT). CASE SUMMARY: Six long-term Hodgkin lymphoma survivors developed isolated, nonischemic LBBB decades after chest RT. None had prior conduction issues or coronary artery disease on evaluation. We describe in detail 3 patients with new focal LBBB who developed worsening low/normal left ventricular (LV) systolic function and heart failure onset, which improved with cardiac resynchronization therapy. DISCUSSION: Dense calcification of the subaortic/LV outflow tract region was observed on echocardiography, an area included in the RT field overlap for Hodgkin lymphoma and through which the left bundle branch courses after bifurcation from the right bundle. QTc interval prolongation preceded LBBB onset. TAKE-HOME MESSAGES: Patients who received high-dose chest radiation may present with isolated LBBB, without coronary artery disease, decades post-treatment. LBBB may unmask subclinical LV dysfunction and heart failure onset in cancer survivors, which may be reversible with cardiac resynchronization therapy.