Cardioversion corrects cardiac arrhythmia and reverts the resultant reversed shunt flow direction during transcatheter closure of atrial septal defect--a case report.

Closure of atrial septal defect (ASD) is critically dependent on the shunt flow direction. However, shunt flow direction through ASD may change under variable clinical conditions. We present here a 53-year-old woman with a confirmed left-to-right shunt ASD prior to Amplatzer Septal Occluder placement. The development of atrial flutter during the procedure had been found to change the shunt from unidirectional to bidirectional and the procedure was then forced to a temporary halt. The cardiac arrhythmia and altered shunt direction simultaneously reverted to the old state after cardioversion. A successful placement of Amplatzer septal occluder was successfully performed afterward and she recovered uneventfully.