Congenital artrioventricular dissociation due to complete or advanced atrioventricular heart block; clinical and cardiac catheterization findings in twelve children without cardiac malformations, including three siblings.

Abstract

Congenital heart block seldom occurs as an isolated abnormality. Many types of cardiac malformations have been reported with it. Septal defects, either auricular or of the high ventricular type, are by far the commonest of the malformations associated with this conduction disturbance. 1 These comments, published a decade ago, represented the opinion prevailing up to the past several years. Several authors 2-5 have now reported the frequent occurrence of congenital complete atrioventricular block in persons in whom no associated malformations can be demonstrated. In complete atrioventricular heart block there is blockage of all atrial impulses, even when the ventricular rate is very slow, owing to extreme prolongation of the absolute refractory phase of the atrioventricular junctional tissue. 6 In complete atrioventricular dissociation with advanced atrioventricular block, the prolongation of the refractory phase is less, though marked, but the ventricular rate, though slow, is too rapid to allow the penetration of