Idiopathic giant-cell myocarditis
Rare, fatal heart muscle disease with no proven cure.
Idiopathic giant-cell myocarditis (IGCM) attacks the heart muscle. This rare condition is frequently fatal, and because its cause is unknown, no proven cure exists. The disease progresses rapidly, with a mortality rate of about 70% within the first year. Patients often show signs of heart failure, though some first experience ventricular arrhythmia or heart block. The median survival time from diagnosis is roughly six months, and 90% of patients either die or require a heart transplant within a year. Diagnosis is made through an endomyocardial biopsy during heart catheterization, which reveals multinucleated giant cells—hence the name. While heart transplantation was once the only option, recent studies indicate that high doses of immunosuppressants like prednisone and cyclosporine allow two-thirds of patients to survive beyond one year. However, the disease frequently recurs in the transplanted heart. Compared to lymphocytic (presumed viral) myocarditis, giant cell myocarditis is far more severe and progresses much faster. The condition is thought to be driven by T-lymphocytes.
- Field
- Cardiovascular disease
- Known for
- Rare, often fatal myocarditis with multinucleated giant cells on biopsy
- Mortality rate
- ~70% in first year
- Median survival
- ~6 months from diagnosis
- Transplant or death rate
- 90% within 1 year
Lore & Background
Idiopathic giant-cell myocarditis is a rare cardiovascular disease affecting the myocardium. It frequently leads to death, with a high mortality rate of about 70% in the first year. Patients typically present with symptoms of heart failure, though some may initially show ventricular arrhythmia or heart block. The median age from diagnosis to death is approximately 6 months, and 90% of patients are either deceased by the end of one year or have received a heart transplant.
Reader's Guide
Idiopathic giant-cell myocarditis is significant as a rare but highly lethal cardiac condition. Its unknown cause and lack of proven cure make it a challenging disorder. Diagnosis is made by endomyocardial biopsy during heart catheterization, revealing multinucleated giant cells. While previously all cases required heart transplantation, recent studies indicate that two-thirds of patients can survive past one year with high doses of immunosuppressants such as prednisone and cyclosporine. However, the transplanted heart has a high chance of disease recurrence. Compared to lymphocytic (presumed viral) myocarditis, giant cell myocarditis is much more severe with much more rapid progression. The disease is suggested to be caused by T-lymphocytes.
Did You Know?
- The condition is rare but often fatal, with a 70% mortality rate in the first year.
- Diagnosis is made by endomyocardial biopsy showing multinucleated giant cells.
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