Unraveling the mystery: congenital absence of the portal vein and its cardiac implications.

A 25-year-old male with tachycardia and right heart enlargement was diagnosed with atrial-ventricular nodal reentrant tachycardia (AVNRT) and successfully treated with radiofrequency ablation. Cardiac MRI confirmed right heart enlargement but ruled out cardiomyopathy. Further imaging revealed a rare congenital absence of the portal vein (CAPV) with an associated portosystemic shunt. This case highlights the importance of considering CAPV in unexplained cardiac symptoms and structural heart changes.