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The pathogenesis of dilated cardiomyopathy
1Royal Brompton National Heart and Lung Hospital, Department of Histopathology (Cardiovascular Pathology), London, UK.
Insights
Myocarditis, an inflammation of the heart muscle, is a significant factor in dilated cardiomyopathy, affecting 28% of patients. Research is advancing to understand its causes and develop targeted therapies.
Area of Science:
- Cardiology
- Pathology
- Virology
Background:
- Dilated cardiomyopathy's etiology remains largely unknown, prompting research into pathogenetic mechanisms.
- Endomyocardial biopsies have revealed myocarditis as a key factor in dilated cardiomyopathy development.
- Myocarditis diagnosis historically presented challenges, necessitating standardized criteria.
Purpose of the Study:
- To define diagnostic criteria for myocarditis in dilated cardiomyopathy.
- To investigate the etiological agents and pathogenesis of myocarditis.
- To explore therapeutic implications based on myocarditis classification.
Main Methods:
- Utilized the WHO/ISFC nomenclature for cardiomyopathies.
- Established morphological diagnostic criteria for myocarditis in 1984 (Dallas criteria).
- Employed hybridization probes for direct detection of viral causes, moving beyond serological tests.
Main Results:
- Myocarditis identified in 28% of approximately 2,000 patients with presumed dilated cardiomyopathy.
- Dallas criteria provided a framework for categorizing myocarditis (acute, resolving, resolved).
- Coxsackie B viruses confirmed as a primary cause of myocarditis through advanced molecular techniques.
Conclusions:
- Myocarditis is a crucial, identifiable component in the pathogenesis of dilated cardiomyopathy.
- Standardized diagnostic criteria and etiological identification are vital for therapeutic strategies.
- Ongoing research into immunological consequences aims for rationalized treatment approaches for myocarditis-related cardiomyopathy.
Abstract:
Using the WHO/ISFC definition and recommendations of nomenclature for cardiomyopathies, the aetiology is unknown. Over many years research has concentrated on defining pathogenetic mechanisms and owing to the widespread use of the bioptome-permitting recovery of fresh endomyocardial tissue-myocarditis has emerged as being intimately involved in the pathogenesis of dilated cardiomyopathy. In approximately 2,000 patients with a presumed diagnosis of dilated cardiomyopathy, myocarditis was found in 28% of these cases. The morphological diagnosis of myocarditis has been fraught with difficulties and, in attempt to establish criteria for its recognition, a group of cardiovascular pathologists (the author among them) met in Dallas in 1984. These criteria are detailed and categorization into acute, resolving (healing) and resolved (healed) has been emphasized because of important therapeutic implications. The cause of myocarditis has been established as being due to coxsackie B viruses. Up to recent times such findings could only be surmised by investigations such as micro-neutralization tests. It was not until the hydridization probe was employed that direct proof was provided. These studies together with immunological consequences continue to be investigated in the hope of providing a rational approach to therapy.