In this article the author follows the fate of a clot from its venous origin, as is the rule--the domaine of the phlebologist--prevention of the different factors of thrombo-embolic disease, the fight against stasis, phlebological care, treatment to prevent platelet aggregation and anticoagulant treatment. The author also considers the point of view of the cardiologist, the diagnosis and treatment of the "pulmonary embolism heart". The phlebologist has the most important role which is preventive; when a cardiologist intervenes in cases of pulmonary heart, although his role may be curative, it is sometimes still disappointing from both the diagnostic and prognostic points of view.