Instructions: Given an abstract, generate a keyword (a noun phrase) that best describes the focus or contribution of the paper. Such keywords can be directly from the given abstract or outside it.
Input: Abstract: Endomyocardial biopsy is most frequently used to establish a definitive diagnosis of myocarditis, especially since this disorder has been treated with immunosuppressive therapy. Recent diagnostic criteria (the "Dallas Classification") are reviewed, and pitfalls and limitations are discussed.
Output:
Biopsy