A case of a giant cell myocarditis that developed massive left ventricular thrombus during percutaneous cardiopulmonary support.

We present a patient with giant cell myocarditis who developed widespread thrombosis in the left ventricle during the circulatory support with PCPS, despite anticoagulant therapy. In this case, decreased left myocardial contractility caused by giant cell myocarditis and increased left ventricular afterload by the retrograde perfusion from the PCPS induced the thrombotic tendency and congestion in the left ventricle. In addition, he developed complete atrioventricular block, which reduced the left ventricular ejection and enhanced the thrombus formation. Because patients with giant cell myocarditis have a low probability of spontaneous recovery, heart transplantation or ventricular assist device implantation may be required for circulatory support. We should establish mechanical circulatory support rapidly to improve the prognosis of patients with giant cell myocarditis. Moreover, a ventricular assist device, which can prevent both ventricular congestion and retrograde blood flow, might be suitable to prevent complications as this case.