A healthy teenage Japanese girl was admitted to our hospital after experiencing out-of-hospital cardiac arrest. She had attempted to commit suicide by taking 4,950 mg of disopyramide and 12 mg of flunitrazepam. Mechanical cardiopulmonary support was started with percutaneous cannulation of the femoral vessels. Several days later, a blood culture tested positive for Staphylococcus aureus. Transthoracic echocardiography showed a large mobile and solid mass attached to the apical part of the left ventricle. To the best of our knowledge, the anatomical location of a pedunculated mass originating from the apex is a rare condition.