The diagnosis of dilated cardiomyopathy is the result of a complex and systematic analysis of patients and familial history, clinical data and instrumental evaluation. In the traditional diagnostic procedure of idiopathic dilated cardiomyopathy, echocardiography represents the most important tool, thanks to its large spreading, low cost and fair reproducibility. Echocardiography can well evaluate the typical morphological and functional abnormalities of dilated cardiomyopathy. However, left ventricular dysfunction can also be found in other diseases and non-invasive evaluation alone does not allow for an accurate diagnostic characterization. Thus, for a definitive diagnosis, invasive study with coronary angiography is usually required due to the relevance of etiological characterization from a therapeutic and prognostic point of view. The diagnostic role of other non-invasive studies is limited, considering their cost and limited availability. Endomyocardial biopsy has become a useful diagnostic tool for the investigation and treatment of myocardial diseases. Mainly, its role is irreplaceable in the diagnosis of acute myocarditis, particularly in selected cases of recent-onset heart failure with relevant left ventricular dysfunction and sustained ventricular arrhythmias. Furthermore, the information derived from endomyocardial biopsy is increased by the number of methodologies we apply. Thus, it is necessary for traditional histology (Dallas criteria) to be completed by immunohistochemical ultrastructural and molecular biological techniques, which can improve the accuracy of the analysis. As regards the therapeutic perspectives, endomyocardial biopsy may have a role in a few clinical cases, despite the persistent perplexity about the effective treatment of active myocarditis. The identification of therapeutic options for the patient should be the final result of a close cooperation between clinicians and pathologists. Finally, in patients with heart failure, an infiltrative disease, mitochondrial cardiomyopathy and other heart muscle diseases (dystrophinopathies, dystrophin-associated glycoprotein disease, laminopathies, emerinopathies) could be better and thoroughly analyzed through an endomyocardial biopsy, with a significant diagnostic, and prognostic contribution. Dilated cardiomyopathy is considered to be the final common phenotype of a heterogeneous group of disorders as viral infections, autoimmune disorders or genetic abnormalities. A familial trait is present in a least 25-30 % of cases, indicating a major role of genetic factors. As a matter of fact, some apparently sporadic cases may also have a genetic background, as a result of new mutations, low penetrance of the disease or in case of low informative families. However, in a large number of patients, the cause of the disease is still unknown. From a clinical point of view, sporadic and familial cases are not easily distinguishable, generally showing a low phenotypic heterogeneity of the disease, at least regarding the main clinical findings of heart failure and left ventricular dysfunction. In fact, different genetic, metabolic or structural defects can lead to a common phenotype of myocardial damage. On the other hand, some phenotypic characteristics (i.e. atrioventricular block), the pattern of genetic transmission, and molecular genetic findings have allowed the characterization of different forms of familial dilated cardiomyopathy, suggesting genetic heterogeneity. The risk of disease has been estimated as high as 20% in relatives of familial cases, which is significantly higher than in the normal population. Taking into account that dilated cardiomyopathy can be clinically not evident due to its low penetrance (in particular in the young population), a reproducible and reliable method for the diagnosis of familial forms is of the utmost importance in the management of the disease. In order to discuss this issue, consensus guidelines for the diagnosis and screening of familial dilated cardiomyopathy have been proposed; they should be implemented on the basis of knowledge progressively emerging from research. There is no doubt that the rigorous approach used in defining the prevalence of familial diseases and identifying asymptomatic subjects is based on a clinical and non-invasive screening of first-degree family members of consecutive index patients. The family screening should be followed up every 2 to 3 years, in particular in unaffected relatives (in absence of a molecular diagnosis) in order to exclude a late onset of the disease. A systematic clinical evaluation of the neuromuscular apparatus should be included, due to the frequent and sometimes subtle involvement of the striated muscle. Familial dilated cardiomyopathy is commonly inherited as autosomal dominant trait; less frequently, the disease is autosomal recessive, X-linked or matrilineal, although the information on molcular diagnoses that can be provided to patients is limited to a few X-linked, autosomal dominant and matrilineal cases (overall, about 10% of all dilated cardiomyopathy patients). The new clinical approach of familial dilated cardiomyopathy studies, based on the screening of family members, will bring to the cardiologist's attention both patients and relatives, and it will help to extend the clinical evaluation to subjects who are still healthy, thus making it possible to early identify and treat patients at risk. In this issue of the Italian Heart Journal Supplement, we collected some important contributions on this topic written by various experts of the field, presenting a deep experience on the study, treatment and follow-up of patients with dilated cardiomyopathy. We sincerely thank them.
|Translated title of the contribution||Diagnosis of dilated cardiomyopathy: How to improve clinical and etiological definition|
|Number of pages||3|
|Journal||Italian Heart Journal Supplement|
|Publication status||Published - 2002|
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine