Conclusion:
In this case, a right pulmonary artery to left atrium fistula was diagnosed as the cause of unexplained cyanosis in 3.5 years old child. The diagnosis was confirmed based on cardiac angiography through cardiac catheterization, and the underlying anatomy of the pulmonary vasculature and its relationship with the left atrium was visualized using multi-slice CT.
This case is of significant importance because classification of fistula does not correspond to the classifications mentioned previously in the medical literature. Surgical repair was performed after diagnosis to prevent the serious complications of the fistula. The patient’s oxygenation and symptoms improved immediately after surgery and persisted on follow-up after 6 months.