Flow-Driven Right-to-Left Shunting Through the Patent Foramen Ovale Causing Hypoxemia and Embolism in a Partial Uhl...

Uhl anomaly is an exceptionally rare congenital disorder, with fewer than 100 cases reported. In this setting, a patent foramen ovale may become clinically relevant through non-pressure-dependent hemodynamic mechanisms.

A 49-year-old woman presented with progressive dyspnea and a prior ischemic stroke. Multimodality imaging demonstrated diffuse right ventricular myocardial thinning with global systolic dysfunction and torrential functional tricuspid regurgitation, consistent with partial Uhl anomaly. Despite normal right-sided pressures, a permanent right-to-left shunt through the patent foramen ovale was identified, predominantly driven by flow redirection related to severe tricuspid regurgitation.

In rare conditions such as partial Uhl anomaly, integration of multimodality imaging and invasive hemodynamics is essential to establish the diagnosis and to elucidate unconventional mechanisms underlying clinical events.

Partial Uhl anomaly should be considered in adults presenting with unexplained right ventricular dysfunction. Flow-driven right-to-left shunting through a patent foramen ovale may be a major determinant of hypoxemia and embolic risk.