Free-floating thrombus in the right ventricle, associated with a massive acute pulmonary embolism (PE), is a rare phenomenon. PE is an important clinical entity with considerable mortality despite advances in diagnosis and treatment. The prognosis of PE depends on right ventricular dysfunction, myocardial injury markers, and early treatment. In this report, we present the case of a 71-year-old woman with a history of breast cancer admitted to intensive care unit for PE complicated by syncope. Although our case may seem complex because it is not represented in the guidelines, the result was satisfactory and showed how treatment with new anticoagulants (in this case apixaban) after massive thrombolysis of PE could be considered and included in the new guidelines.