Pulmonary embolism (PE) is a common disease with a high mortality rate due to right ventricular dysfunction and underfilling of the left ventricle. We present a case of a 33-year-old man with hemodynamically compromised massive PE. His left atrium was collapsed with marked dilatation of the right atrium and ventricle on multi-detector-row CT scans. The patient was treated with an intracatheter injection of a mutant tissue-type plasminogen activator and subsequently showed clinical and radiological improvements. The small left atrial size in combination with a right ventricular pressure overload was considered to be an adjunctive sign of hemodynamically compromised massive PE.