Although echocardiography detected right-sided heart thrombi are frequently associated with massive pulmonary embolism and death, there are conflicting recommendations in the literature about the optimal treatment of this condition. Our objective was to resolve this uncertainty by pooling all existing English language case reports in order to examine the relationship of treatment with survival. There were 71 published reports involving 119 subjects, of which 93% presented with abnormal cardiac signs and symptoms and 7% were asymptomatic but had risk factors for pulmonary embolism. The only factors that were significantly related to survival were whether pulmonary emboli were present, and the type of treatment actually received. Variables not significantly related to survival included cardiac symptoms and the echocardiographic appearance of the thrombus. The estimated probability of survival in patients with pulmonary emboli receiving heparin, thrombolytic agents, surgical embolectomy, or none of the above, was 0.70, 0.62, 0.62, and 0.19, respectively, while the estimated probability of survival in patients without pulmonary emboli for the same four treatment groups, was 0.92, 0.89, 0.89, and 0.53, respectively. We conclude that the efficacy of all three treatments are similar, and that they enhance the probability of survival. Because of the similar efficacy of drug therapy and surgery and the convenience of the former, drug therapy should probably be chosen. In addition, considering the small advantage of heparin with respect to the probability of survival, heparin may be the best choice if the illness is not characterized by a rapid downhill course.