Inferior type sinus venosus atrial septal defect: MR findings.

Atrial septal defects can occur at various levels of the interatrial septum. Sinus venosus atrial septal defect (SVASD) results from abnormal resorption of the embryologic sinus venosus, and may be of the superior or inferior type. In this paper, we describe a 46-year-old man with inferior-type SVASD who presented with arrhythmias and dyspnea. Cardiac magnetic resonance and cardiac catheterization were useful in evaluating the anatomic/functional characteristics of inferior-type SVASD and distinguishing it from unroofed coronary sinus.