Abstract: A device for exploration of the cardiovascular system of human or animal bodies includes a generally transparent blind tube delimiting a cavity in which can be disposed an optical display device, the open end of the tube being shaped to be ensleeved axially in a sealed manner in the passage of an artery or of a vein having first been at least partially sectioned such that the cavity of the tube in the interior of the artery or of the vein form a common chamber at least partially closeable by a cardiac valve. The tube, maintained in ensleeved position by a suitable securement member, includes at least one supplemental opening for the introduction into the cavity of the tube of a physiological liquid under pressure.