BACKGROUND: Giant cell myocarditis is a rapidly progressive and often fatal condition without a clear etiology or treatment. A better understanding of giant cell myocarditis pathogenesis is critical to developing treatments to prevent progression and reverse damage. We compared the gene expression of giant cell myocarditis with that of nonfailing hearts. METHODS: Left ventricular samples from two giant cell myocarditis patients harvested during ventricular assist device placement and six unused donor hearts were examined using Affymetrix U133A microarrays. Differential gene expression was defined with a Bonferroni-adjusted p value < or = 0.05 from a Student's t-test and an absolute fold change > or = 2.0. Select gene expression was confirmed with quantitative PCR. RESULTS: Of 115 differentially expressed genes, most were upregulated in giant cell myocarditis and involved in immune response, transcriptional regulation, and metabolism. T-cell activation genes included chemokine receptor 4; chemokine ligands 5, 9, 13, and 18; interleukin-10 receptor alpha; and beta-2 integrin. CONCLUSIONS: Gene expression analysis of giant cell myocarditis offers novel insights into its pathogenesis, namely the role of T-cell activators of the Th1 subset and immune response genes previously implicated in heart failure. This forms the basis for future work aimed at defining novel therapeutic targets for giant cell myocarditis.

Idiopathic giant-cell myocarditis--natural history and treatment. Multicenter Giant Cell Myocarditis Study Group Investigators.N Engl J Med. 1997 Jun 26;336(26):1860-6.

BACKGROUND: Idiopathic giant-cell myocarditis is a rare and frequently fatal disorder. We used a multicenter data base to define the natural history of giant-cell myocarditis and the effect of treatment. METHODS: We identified 63 patients with idiopathic giant-cell myocarditis through journal announcements and direct mailings to cardiovascular centers worldwide. RESULTS: The patients consisted of 33 men and 30 women with an average age of 42.6 years; 88 percent were white, 5 percent were black, 5 percent were Southeast Asian or Indian, and 2 percent were Middle Eastern. Most presented with congestive heart failure (47 patients, or 75 percent), ventricular arrhythmia (9 patients, or 14 percent), or heart block (3 patients, or 5 percent), although in some cases the initial symptoms resembled those of acute myocardial infarction (4 patients). Nineteen percent had associated autoimmune disorders. The rate of survival was worse than among 111 patients with lymphocytic myocarditis in the Myocarditis Treatment Trial (P<0.001); among our patients, the rate of death or cardiac transplantation was 89 percent, and median survival was only 5.5 months from the onset of symptoms. The 22 patients treated with corticosteroids and cyclosporine, azathioprine, or both therapies survived for an average of 12.3 months, as compared with an average of 3.0 months for the 30 patients who received no immunosuppressive therapy (P=0.001). Of the 34 patients who underwent heart transplantation, 9 (26 percent) had a giant-cell infiltrate in the transplanted heart and 1 died of recurrent giant-cell myocarditis. CONCLUSIONS: Giant-cell myocarditis is a disease of relatively young, predominantly healthy adults. Patients usually die of heart failure and ventricular arrhythmia unless cardiac transplantation is performed. Despite the possibility of fatal disease recurrence, transplantation is the treatment of choice for most patients.

Giant cell myocarditis mimicking idiopathic fascicular ventricular tachycardia.J Heart Lung Transplant. 2008 Feb;27(2):238-41.

We report an adolescent with giant cell myocarditis (GCM) mimicking tachycardia-induced cardiomyopathy. His electrocardiogram (ECG) was typical for an incessant form of fascicular ventricular tachycardia. The patient rapidly deteriorated and required support using extracorporeal membrane oxygenation (ECMO). Biopsy revealed GCM with massive myocyte necrosis. He was successfully heart transplanted 6 days after admission.

Giant cell myocarditis triggered by a parvovirus B19 infection. Int J Cardiol. 2008 Feb 14.

Giant cell myocarditis (GCM) is an uncommon inflammatory heart disease with a rapid progression and a devastating outcome. Its exact cause is unknown, but it has been associated with various inflammatory and autoimmune disorders. The authors report a case where GCM is triggered by a parvovirus B19 (PVB19) infection.