Exploring Strategies to Improve Outcomes in Patients With Giant Cell Myocarditis: A Case Series of Five Biopsy-Proven Cases.

Giant cell myocarditis (GCM) is a rare but severe disease with high morbidity and mortality, often requiring heart transplantation (HT). While immunosuppressive therapy has improved outcomes, recurrence after HT remains high, and long-term survival without transplantation is also limited. This case series presents five biopsy-confirmed GCM cases, highlighting clinical characteristics and strategies to improve prognosis. A retrospective analysis was conducted on five GCM patients at Samsung Medical Center (2004-2024). The median age was 57.8 years, and 40% had underlying autoimmune diseases. All patients presented with fulminant heart failure, requiring vasopressor support or mechanical circulatory support (MCS). Early diagnosis facilitated targeted therapy, improving outcomes in select cases. Two patients achieved long-term survival without recurrence. One patient recovered cardiac function and avoided in-hospital mortality but was later readmitted due to infection and subsequently died. The remaining two patients underwent HT but died during hospitalization due to post HT complications. Timely histologic confirmation, early immunosuppressive therapy, and appropriate MCS bridging are critical in GCM management. Larger studies are needed to validate these findings.