Pre-operative sinus node function in adult patients with atrial septal defect (ostium secundum type)

The authors studied, pre-operatively, the sinus node function in adult patients with secundum atrial septal defect and large left-right shunts, using Holter ECG and electrophysiological tests. Sinus node electrophysiological tests were found abnormal in 17 out of 26 patients; on the contrary, Holter monitoring was always within normal limits. The authors believe that concealed sinus node dysfunction existing before surgical correction may be a cause of early, acute, and reversible, post-operative sick sinus syndrome.