Aortic regurgitation and combined ventricular tachycardia due to IgG4-related disease.

IgG4-related disease (IgG4-RD) is a systemic immune-mediated disorder that causes tissue inflammation and fibrosis in affected organs. A 68-year-old woman underwent aortic valve replacement due to severe aortic regurgitation. Aortic valve leaflets showed abnormal thickening, and fibrosclerosis of the subvalvular structure was observed. Histopathology revealed fibromyxoid degeneration with multifocal dense infiltration of IgG4-positive plasma cells and immunostaining confirmed IgG4-positive plasma cells, therefore the patient was clinically diagnosed with IgG4-RD. After discharge, she underwent implantable cardioverter defibrillator implantation and radiofrequency catheter ablation for refractory ventricular tachycardia. If a patient with underlying IgG4-RD develops a valvular disease or arrythmia, it is necessary to consider the possibility that IgG4-RD is the cause and pre/postoperative systemic inflammation control and thorough evaluation must be performed.