How to Image the Adult Patient With Fontan Circulation

A 32-year-old woman was seen for acute chest pain radiating to the neck and arms. The paramedical team witnessed her cardiac arrest on arrival and successfully defibrillated ventricular fibrillation by a single shock. After a stable transfer to the local hospital, she had a second witnessed arrest necessitating further defibrillation. History revealed good functional capacity and no other cardiac symptoms. Examination showed clear lungs, normal heart sounds, a normal abdomen, a blood pressure of 110/79 mm Hg, and an oxygen saturation of 100% (Figure I in the Data Supplement). The ECG showed signs of inferolateral infarction. Cardiac troponin I was 1.06 ng/mL. Telemetry confirmed intermittent nonsustained ventricular tachycardia and sinus bradycardia. Her medical therapy included bisoprolol 2.5 mg and warfarin (International Standardized Ratio, 1.7). Because of tricuspid atresia, transposition of the great arteries, pulmonary stenosis, and ventricular septum defect, she had undergone superior cavo-pulmonary shunt (Glenn) aged 4 years and atrio-pulmonary (Fontan) connection aged 7 years. Three years before, recurrent supraventricular tachycardia necessitated multiple electrophysiological studies, with ablation of focal right atrial tachycardias and cavo-tricuspid isthmus-dependent flutter. Echocardiography showed preserved ventricular function, mild flow acceleration across the subaortic ventricular septum defect, mild mitral regurgitation, as well as dilated systemic and hepatic veins (Movies V and VI in the Data Supplement). Computed tomography (CT) of the pulmonary arteries (PA; computed tomography pulmonary angiogram) was subsequently performed, reporting a large opacification defect in the proximal left PA, suggestive of pulmonary embolism (Figure 1). Cardiac magnetic resonance imaging (CMR) thereafter showed a patent Fontan pathway, no thrombi, and normal pulmonary arborization. The coronary sinus, the right atrial, the cardiac, hepatic, and the systemic veins were severely distended (inferior vena cava; Figures 2 and 3; Movies I-III in the Data Supplement), with diastolic flow reversal in the inferior vena cava. No systemic-to-pulmonary collaterals (SPC) …