Giant Cell Myocarditis Treatment — EECC MCQ

Correct answer: E — GCM requires aggressive combined immunosuppression (cyclosporine + corticosteroids ± azathioprine/muromonab) — it has a rapidly progressive course with median transplant-free survival of only 5 months without immunosuppression; unlike lymphocytic myocarditis, watchful waiting is not appropriate

Giant cell myocarditis (GCM) is a rare but devastating autoimmune condition characterised by multinucleated giant cells with myocyte destruction on biopsy. Without treatment, median transplant-free survival is ~5.5 months. The 2025 ESC Myocarditis/Pericarditis Guidelines distinguish GCM from lymphocytic myocarditis: (1) GCM: rapid progression, often presenting with acute HF or VT; aggressive combined immunosuppression is required (cyclosporine + high-dose corticosteroids ± azathioprine or muromonab-CD3 — based on the GCM Treatment Trial); high recurrence rate (>20% even in transplanted hearts); (2) Lymphocytic myocarditis: often self-limiting; immunosuppression only for virus-negative inflammatory cardiomyopathy (TIMIC trial). Endomyocardial biopsy is essential for diagnosis — GCM cannot be diagnosed by CMR alone. Heart transplant assessment should be initiated early.

Reference: ESC (2025): Myocarditis/Pericarditis Guidelines