Progressive disease of the atrioventricular conduction axis in an infant of an anti-Ro positive mother.

A child of a mother with maternal anti-Ro and anti-La antibodies presented antenatally with abnormal myocardial function, and was found to have a first degree heart block at birth. The extent of the abnormality in the conduction system progressed, with appearance of left bundle branch block in addition to further prolongation of PR interval. A pacemaker was implanted prophylactically, but patient has remained well, with no further deterioration in her atrioventricular conduction.