Histopathological criteria of myocarditis--a study based on normal heart, chagasic heart and dilated cardiomyopathy
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M de L Higuchi1, C F De Morais, N V Sambiase
1Division of Pathology of Heart Institute (Instituto do Caracao), Sao Paulo Medical School, Sao Paulo University, Brazil.
Insights
This study evaluated three criteria for diagnosing myocarditis, finding the authors' modified Dallas criterion most effective. It identified myocarditis in 92% of chronic chagasic patients and 33% of dilated cardiomyopathy patients.
Area of Science:
- Cardiology
- Pathology
- Immunology
Background:
- Myocarditis diagnosis relies on specific histological criteria.
- Existing criteria like Dallas and Edwards may have limitations in sensitivity.
- Chagasic cardiomyopathy and dilated cardiomyopathy present diagnostic challenges for myocarditis.
Purpose of the Study:
- To compare the diagnostic relevance of three criteria for myocarditis.
- To evaluate the efficacy of the Dallas criterion, Edwards criterion, and a modified Dallas criterion.
- To determine the most appropriate criterion for identifying myocarditis in various patient groups.
Main Methods:
- Histopathological analysis of endomyocardial biopsies and autopsied hearts.
- Application and comparison of three distinct myocarditis diagnostic criteria.
- Evaluation of normal hearts, chronic chagasic hearts, and hearts from patients with dilated cardiomyopathy.
Main Results:
- The authors' modified Dallas criterion identified myocarditis in 92% of chronic chagasic patients, significantly higher than Edwards (67%) and Dallas (42%) criteria.
- For dilated cardiomyopathy patients, the modified criterion showed 33% incidence, compared to 7% (Edwards) and 22% (Dallas).
- Myocarditis was detected in 33% of 27 endomyocardial biopsy specimens from DCM patients using the authors' criterion.
Conclusions:
- The authors' modified Dallas criterion is proposed as the most appropriate for diagnosing myocarditis.
- This criterion, focusing on inflammatory cells aggregated to cardiac sarcolemma, enhances diagnostic accuracy.
- Myocarditis is prevalent in chronic chagasic patients and a significant finding in dilated cardiomyopathy.
Abstract:
This work is a detailed study of the relevance of three sets of criteria to define myocarditis: Dallas meeting criterion, Edwards criterion and Dallas meeting criterion modified by the authors. Two groups were evaluated: normal autopsied hearts and endomyocardial biopsy from chronic chagasic patients at high risk of having myocarditis. Furthermore, endomyocardial biopsies from patients with dilated cardiomyopathy (DCM) were also evaluated. Applying the Edwards criterion, incidences of myocarditis in normal and chagasic hearts were 0% and 67% while with Dallas meeting criterion they were 0% and 42% and using our criterion the incidences were 0% and 92% respectively. In endomyocardial biopsies from DCM patients, the incidence of myocarditis was 7% with Edwards criterion, 22% with Dallas meeting and 33% with the authors own criterion. The authors concluded that their criterion, which defines myocarditis as the presence of inflammatory mononuclear cells enclosing more than 2 lymphocytes/400X aggregated to the cardiac fiber sarcolemma, is the most appropriate criterion of the three. Myocarditis was found in 33% of the 27 endomyocardial biopsy specimens from patients with DCM.