["Idiopathic" chronic paralysis and dilatation of the right atrium].

Electric and mechanical atrial paralysis is a condition usually associated with a primitive or secondary cardiopathy. Only extremely rare cases are characterized by early appearance in young subjects without evidence of cardiac disease of any kind whatever, without character of familiarity, with atrial paralysis being the only abnormality, and are thus defined as idiopathic atrial paralysis. One of these cases (the eighth in the literature, to our knowledge), presented with a complete study and the hypothesis that "chronic idiopathic atrial paralysis" and "idiopathic right atrial enlargement" (sometimes associated, as in this case) may be different manifestations of the same chronic myocardial disease.