Sinus node dysfunction during transcatheter assessment and stent correction of sinus venosus atrial septal defects

Covered stent correction of a superior sinus venosus atrial septal defect is increasingly performed as an alternative to surgical repair. While sinus node dysfunction requiring pacemaker implantation may be required after surgical repair, this has not been previously reported after covered stent implantation. We reviewed the experience in two interventional centers. Balloon inflation in the superior vena cava was used to confirm the anomalous pulmonary vein drainage would be unobstructed after stent implantation. During balloon testing in 62 consecutive patients, we assessed gradients across the pulmonary vein to left atrium while monitoring the rhythm. We observed the outcomes after covered stent correction in 51 patients. In a single patient, significant bradycardia and pauses developed on repeat balloon testing and the procedure was abandoned without stent implantation. In another patient, there was no sign of sinus node dysfunction during balloon testing but several hours after stent implantation, the patient became symptomatic from sinus bradycardia and pauses and had a pacemaker implanted 3 days later. Over a year later there are some signs of improvement in sinus node function. While sinus node dysfunction has not been described previously during balloon testing or after stent implantation, this report demonstrates for the first time that it may occur. Larger registries are therefore required to monitor for this uncommon complication.