ARRHYTHMOGENIC RIGHT-VENTRICULAR CARDIOMYOPATHY - A STILL UNDERRECOGNIZED CLINIC ENTITY

Arrhythmogenic right ventricular cai cardiomyopathy is a new, morbid e ntity that was discovered thanks to the study of sudden death in the y oung. This heart muscle disease is characterized by myocardial atrophy , mostly of the right ventricle, with massive fibro-fatty infiltration , accounting for ventricular electrical instability at risk of severe arrhythmias and even cardiac arrest. The disease was found to be the m ajor cause of sudden death in young people and athletes in the Veneto Region, Italy. A familial occurrence with autosomal dominant transmiss ion was then discovered and the prevalence was estimated to be higher than 1 in 5000. The disease is genetically heterogeneous: Linkage anal ysis, carried out in a large family with recurrence of sudden deaths, Zed to map the gene to chromosome 14q23-q24. Linkage analysis in a sec ond family allowed mapping of another gene to chromosome 1q42-q43. Cli nical diagnosis can be achieved through electrocardiography, echocardi ography, angiocardiography, magnetic resonance imaging, and endomyocar dial biopsy. Diagnostic criteria have been put forward by a committee of the International Society and Federation of Cardiology. The disease was recently included among the cardiomyopathies in the revised World Health Organization (WHO) classification. Study of the natural histor y allowed us to distinguish (a) a covert phase in apparently normal su bjects who have a risk of abrupt electrical instability and sudden dea th, (b) an overt arrhythmic phase with palpitations and impending card iac arrest, (ci congestive heart failure with pump depression, sometim es so severe as to require heart transplantation. Both the etiology an d pathogenesis of the disease ave unknown. In particular the mechanism s leading to progressive loss of myocardium and fibro-fatty replacemen t are still speculative. Apoptosis in the right ventricle occurring no t only in infancy, as in the normal heart, but also in childhood and a dulthood might account for the progressive disappearance of myocardial tissue. (C) 1997, Elsevier Science Inc.