Introduction:Thrombosis of the right cavities is rare, it concerns 4% of pulmonary emboli in the ICOPER register. This prevalence is probably underestimated . It must be considered as an immediate vital threat untreated, mortality is 80 to 100% Observation:We will report the case of a patient, hospitalized in the intensive care unit after a neoplastic surgery of the esophagus and for whom a transthoracic ultrasound performed because of respiratory distress and tachycardia objectified a right ventricular intracavitary thrombosis. Discussion:The presence of a moving right intra-atrial mass during pulmonary embolism confers a higher risk of death to the patient. This localization of thrombi could be explained by an embolization resulting from peripheral venous thrombosis , an impaired right ventricular systolic function an atrial rhythm disorder or a simple dilation of the atria. Authors have reported mechanisms caused by central venous catheter carbon monoxide poisoning . Heparin alone is insufficient in these patients, treatment may involve either surgical thrombectomy or intravenous thrombolysis. the generalization of ultrasound in the emergency and resuscitation departments as well as the training of practitioners should make it possible to diagnose thrombosis of the right heart chambers more early and, more generally, the existence of an acute pulmonary heart . Conclusion:Thrombosis of the right cavities is rare, it concerns 4% of pulmonary emboli Heparin alone is insufficient in these patients, even when the clinical condition is stable. Treatment may involve either surgical thrombectomy or intravenous thrombolysis. Therapeutic diagnosis and management is an emergency, because if not treated in time, the mortality is 80 to 100%.