Platypnea-Orthodeoxia Syndrome Due to Venovenous Malformation

A rare cause of platypnea‐orthodeoxia syndrome in a young female due to persistent left superior vena cava

“…POS remains a rare clinical condition defined by dyspnea and desaturation in the upright position with resolution of these signs and symptoms in the supine position. 1,2 The desaturation, orthodeoxia, has several definitions including a drop in partial pressure of oxygen by more than 4 mmHg or a decrease in saturation by more than 5% from the upright to supine positions 3 or saturation less than 90% or partial oxygen pressure less than 60 mmHg in upright position with normalization in lying position. 10 About 87% of patients with POS have intracardiac shunting, most commonly from patent foramen ovale.…”

“…3 Our patient had POS in the context of physiological right-to-left shunt without pulmonary arterial hypertension. 8,9 PLSVC is a rare congenital anomaly, most frequently diagnosed incidentally with an incidence of 0.3% in general population. 11 The incidence is higher in patients with congenital heart disease reaching 4%.…”

“…Platypnea-Orthodeoxia syndrome (POS) is a rare clinical syndrome characterized by shortness of breath and hypoxia in the upright position that is relieved with supine positioning. 1,2 The etiologies of POS include intracardiac right-to-left shunt, extracardiac abnormalities like pulmonary arterio-venous malformation, hepato-pulmonary syndrome and ventilation/perfusion mismatch. 3,4,5,6 On very rare occasion, a persistent left superior vena cava (PLSVC) may lead to POS by draining into left atrium and causing physiological right-to-left shunt leading to hypoxia and dyspnea.…”