•  Exclusion of potential common etiologies of dilated cardiomyopathy (familial; ischemic; alcohol; postpartum; cardiotoxic exposures) and the following:

•  Subacute or acute symptoms of heart failure refractory to standard management.

•  Substantial worsening of EF despite optimized pharmacological therapy.

•  Development of hemodynamically significant arrhythmias, particularly progressive heart block and ventricular tachycardia.

•  Heart failure with concurrent rash, fever, or peripheral eosinophilia.

•  History of collagen vascular disease such as systemic lupus erythematosus, scleroderma, or polyarteritis nodosum.

•  New-onset cardiomyopathy in the presence of known amyloidosis, sarcoidosis, or hemachromatosis.

•  Suspicion for giant cell myocarditis (young age, new subacute heart failure, or progressive arrhythmia without apparent etiology).