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A morphological analysis of chronic myocarditis
1Department of Internal Medicine, School of Medicine, Juntendo University, Tokyo, Japan.
Insights
Chronic myocarditis (CM) patients exhibit cardiac changes similar to fibrosis-type dilated cardiomyopathy (DCM). This study found CM involves fewer myocardial cells and increased fibrosis, impacting heart structure.
Area of Science:
- Cardiology
- Pathology
- Morphometry
Background:
- Chronic myocarditis (CM) and dilated cardiomyopathy (DCM) are significant cardiac conditions.
- Understanding the morphometric differences between CM and DCM is crucial for diagnosis and treatment.
- Fibrosis is a key pathological feature in several cardiac diseases.
Purpose of the Study:
- To compare the morphometric characteristics of patients with chronic myocarditis (CM) to those with dilated cardiomyopathy (DCM) and healthy controls.
- To identify specific structural changes associated with CM.
Main Methods:
- Morphometric analysis was performed on eight CM patients, 27 DCM patients (fibrosis and non-fibrosis types), and 10 controls.
- Key parameters measured included heart weight, left ventricular wall thickness, myocyte layer count, myocyte size, and percentage of fibrosis.
Main Results:
- Patients with CM showed a decreased number of myocardial cells and an increased area of myocardial fibrosis.
- The morphometric profile of CM patients closely resembled that of patients with fibrosis type DCM.
- Specific measurements for CM patients included a mean age of 43.5 years, heart weight of 448 g, and 29.1% fibrosis.
Conclusions:
- Chronic myocarditis shares significant morphometric similarities with fibrosis-type dilated cardiomyopathy.
- The observed changes in CM are primarily attributed to a reduction in myocardial cell number and an increase in fibrosis.
- These findings highlight the importance of fibrosis as a common pathological element in both conditions.
Abstract:
Eight patients with chronic myocarditis (CM), 2 showing postmyocarditis and 6 showing dilated heart with severe diffuse cell infiltration, were compared morphometrically with 27 patients with dilated cardiomyopathy (DCM, 8 with fibrosis type DCM and 19 with non-fibrosis type DCM) and 10 controls. Patients with CM had a mean age of 43.5 years (range, 17-75 years), a mean duration of clinical illness of 45.5 months, heart weight of 448 g, left ventricular wall thickness of 8 mm, number of myocyte layers of the stratum compactum layer of the left ventricle (Nf) of 125, myocyte size of 19.1 micron, and % area of fibrosis of 29.1%. The morphometric profile of patients with CM resembled that of patients with fibrosis type DCM; this appeared to be due primarily to a decrease in the number of myocardial cells and an increase in myocardial fibrosis.