Fulminant Giant Cell Myocarditis Is Associated With Poor Outcomes

Abstract

Background Giant cell myocarditis (GCM) is a rare autoimmune disorder that typically manifests with signs and symptoms of congestive heart failure, ventricular arrhythmias, or heart block. Diagnosis requires myocardial tissue to detect inflammatory infiltrates, with multinucleated giant cells and prominent myocyte necrosis. With immunosuppressive therapy, transplant-free 5-year survival rates range from approximately 40% to 60% across studies. However, the majority of published literature involves the entire spectrum of GCM, with minimal data on patients who present in cardiogenic shock. We hypothesized that patients who were critically-ill at presentation (fulminant myocarditis) would have a high likelihood of requiring advanced cardiac therapies, such as left ventricular assist device or heart transplantation (OHT). We report the demographics and outcomes of patients at a single-center who presented in fulminant giant cell myocarditis. Methods A natural language search for “giant cell myocarditis” was used to identify patients with a pathological diagnosis of GCM at the Vanderbilt University Medical Center between 1990 and 2020. Chart review of the results identified 7 patients who experienced cardiogenic shock during the index admission. Demographics, admission characteristics, and outcomes were analyzed. Results Major findings are shown in Figure 1. The median age at presentation was 53 years, with two of the seven patients having a history of left ventricular dysfunction. In all 7 patients, symptom-onset was within 30 days of presentation. The majority of patients experienced either ventricular arrhythmias or heart block. Hemodynamic assessment was consistent with cardiogenic shock, with elevated filling pressures and a median Fick cardiac index of 1.60 L/min/m2. All patients required support with at least one vasoactive agent. Five patients required an intra-aortic balloon pump, with two requiring escalation to extracorporeal membrane oxygenation (ECMO). Another patient required ECMO as the initial form of mechanical circulatory support. 30-day survival was 42.9%. Of the seven patients, three received steroids while another received a combination of steroids, thymoglobulin, and cyclosporine. The remaining three patients did not receive immunosuppressive therapy. Both the patients who survived for at least 1 year required OHT. Conclusions These findings suggest that GCM resulting in cardiogenic shock is rapidly progressive and highly lethal. Early mechanical circulatory support and urgent evaluation for advanced cardiac therapies may help improve outcomes. Large-scale studies are warranted to better understand this disease process.