ARRHYTHMOGENIC RIGHT VENTRICLE - DYSPLASI A OR CARDIOMYOPATHY - VALUEOF THE LEFT-VENTRICULAR EJECTION FRACTION

The left ventricular ejection fraction (LVEF) of 76 patients suffering from arrhythmogenic dysplasia or cardiomyopathy of the right ventricl e (ventricular tachycardia associated with structural abnormalities of the right ventricle) demonstrated two subgroups situated above and be low 45 %. Values of LVEF less than 45 % were similar to those of a con trol population of 6 cases of idiopathic dilated cardiomyopathy with v entricular tachycardia of left ventricular origin (p = 0.2). These pat ients also have the same unfavourable long-term prognosis. Histologica l data obtained from four cases belonging to the group of patients wit h dysplasia or cardiomyopathy of the right ventricle with a low ejecti on fraction demonstrated the presence of signs of myocarditis involvin g both ventricles. This suggests that these patients may suffer from a n infectious phenomenon superimposed on a specific histological substr ate, which may lead to deterioration of their myocardial function. The se results are in line with those of the literature. The term arrhythm ogenic cardiomyopathy of the right ventricle should therefore be reser ved to the subgroup of patients with an LVEF less than 45 %. Finally, arrhythmogenic cardiomyopathy of the right ventricle appears to be a c omplication of dysplasia following the development of a myocarditic ph enomenon. This may explain the wide range of clinical forms observed i n patients with ventricular tachycardia of right ventricular origin as sociated with structural abnormalities of the right ventricle.