Cardiac manifestations of IgG4-related disease: a case series.

Background: IgG4-related disease (IgG4-RD) is an autoimmune condition affecting almost every organ system, with an early inflammatory phase and later fibrotic consequences. Vascular manifestations, particularly, large-vessel involvement in IgG4-RD, are well described. However, important IgG4-related effects on medium-sized arteries and the pericardium are less well recognized. These less frequently reported cardiovascular effects of IgG4-RD include coronary artery stenosis, pericardial disease, cardiac masses, and valvular heart disease. Case summary: This case series focuses on three patients that demonstrate the cardiovascular effects of IgG4-RD and the pitfalls and importance of early diagnosis. Cases 1 and 2 presented with cardiac manifestations prior to more typical organ systems being affected which led to a delay in diagnosis. Case 1 presented with an acute myocardial infarction secondary to IgG4-RD of the coronary arteries and Case 2 presented with pericarditis which progressed to pericardial constriction due to IgG4-RD. Case 3 already had a diagnosis of IgG4-RD from a prior renal biopsy which raised the index of suspicion that his pericardial disease and thoracic mass were also related to IgG4-RD. Discussion: Cardiac manifestations of IgG4-RD remain under-recognized and include coronary artery and pericardial disease. These manifestations often precede more typical manifestations in other organ systems. Recognizing cardiac manifestations of IgG4-RD on cardiac imaging can raise clinical suspicion and act as a catalyst to ascertain a confirmatory diagnosis. Early diagnosis and treatment are crucial to prevent potentially fatal outcomes and irreversible fibrosis.