Portable echocardiography revealed RV dilatation with free wall hypokinesia, and an about 6 × 3 cm sized highly mobile, villo-papillary mass in RA with to and fro motion through the tricuspid valve (Fig. 2A and Supplementary Video 1). Sudden loss of consciousness and pulseless electrical activity were developed, and echocardiography revealed non-visualization of RA masses with total RV akinesia (Fig. 2B and Supplementary Video 2). Cardiopulmonary resuscitation and simultaneously extracorporeal membrane oxygenation (ECMO) support were performed. Follow-up chest CT revealed disappearance of the previously noted RA mass and no contrast enhancement of pulmonary arterial trees (Fig. 1C).

Emergent surgery revealed a small residual mass in the RA interatrial septum. Pulmonary arterial trees were totally occluded by fragile and mucoid masses which were removed by using forceps and suction (Fig. 3A). Postoperative CT revealed complete visualization of both pulmonary arteries (Fig. 1D). The masses were myxomas on histopathology (Fig. 3B). ECMO was successfully removed on the 5th hospital day.

To the best of our knowledge, this is the first case demonstrating sudden cardiac death due to total occlusion of whole pulmonary arterial trees by the embolization of huge RA myxomas during echocardiography. The present case gives several important messages. First, life-threatening complications may develop suddenly by embolization of myxomas, even in asymptomatic subjects (12). Second, prompt surgical removal should be considered in patients with high risk morphologic features of embolization (3). Third, ECMO can be a useful bridge therapy for cardiogenic shock by the embolization of myxomas before performing definitive surgical therapy (45).