Kaitalidou E.; Karapiperis D.; Makrakis V.; Kipourou M.; Petroglou D. 42)Abstract: A male patient with a history of immobilization due to motor weakness, was transferred to our emergency department after syncope during physiotherapy, with recorded hypotension. Transthoracic echocardiography showed severe dilatation of the right ventricle (RV), with apex hypercontractility and almost akinetic RV free wall. The above findings, in addition to the unexpected visualization of a large, free-floating, right atrial thrombus, a rare finding associated with high mortality, readily confirmed the clinical suspicion of acute pulmonary embolism (PE) causing circulatory collapse. Intravenous fibrinolysis and vasopressor therapy were successfully administered, and hemodynamic instability was soon alleviated.