Silent in situ thrombus within a hypoplastic left ventricle in a teenager with Fontan palliation.

Thrombosis, especially in the Fontan pathway, is one of the major concerns in patients who underwent Fontan surgery, with reported prevalence of 5-33%. We report a case of thrombus in a rudimentary left ventricle in teenager with no arrhythmia or neurological complications. We also report the special concerns of silent thrombus and role of cardiac MRI in diagnosing an intracardiac thrombus.