Atrioventricular nodal function in progressive systemic sclerosis: electrophysiological and morphological findings.

Electrophysiological data consistent with atrioventricular nodal dysfunction were obtained in 10 out of 19 patients with progressive systemic sclerosis (scleroderma). Conducting system studies were carried out in a further seven patients with progressive systemic sclerosis. In each the proximal portion of the atrioventricular node was consistently found to be smaller and more slender. It is postulated that there is a relation between proximal atrioventricular nodal structural alterations and impaired atrioventricular nodal function.