Atypical electromechanical dissociation in a patient with recurrent pulmonary embolism.

A 47-year-old man experienced recurrent pulmonary embolism resistant to aggressive medical and surgical prophylaxis. Although paraneoplastic hypercoagulability was suspected, no endoscopic or radiologic signs of malignancy were detected. Death was the result of electromechanical dissociation, which was attributed to right ventricular outflow obstruction. At autopsy, anaplastic lung carcinoma was found in the left basal segment with superimposed pulmonary infarction. A huge pedunculated thrombus was attached to the left ventricular apex and extended into the ascending aorta, obstructing the left ventricular outflow. To our knowledge, this is the first case of electromechanical dissociation due to left ventricular thrombus in a patient with pulmonary embolism. Radiologic and echocardiographic evaluation of such patients should take into account possible masking of the underlying neoplasm by embolic or hemorrhagic phenomena, or both, and the presence of left-sided cardiac thombi, which may cause catastrophic events.