Familial idiopathic dilatation of the right atrium with complete atrio-ventricular block: a new syndrome?

Familial occurrence of idiopathic dilatation of the right atrium is extremely rare. This is the first description of a family in which 2 siblings had a syndrome of idiopathic dilatation of the right atrium associated with complete atrio-ventricular block. The family workup did not show other family members to be affected, and the question we raise is whether or not this might be a new syndrome.