To re-emphasize the epidemiology, pathophysiology, diagnosis, and treatment of cardiac tamponade.Cardiac tamponade is a cause of obstructive shock. Incidence of cardiac tamponade is poorly documented. In cardiac tamponade, the pericardial pressure may reach 15-20 mmHg, leading to an equalization of pressures into the cardiac chambers and to a huge decrease in the systemic venous return. The right atrial transmural pressure becomes negligible. A competition between the right atrium and the right ventricle and between both ventricles is occurring. Deep inspiration allows the patients to maintain the systemic venous return at a certain level. Echocardiography is the key tool to diagnose a pericardial effusion, to detect its bad-tolerance, and to guide the treatment. In some situations following cardiac surgery, transesophageal echocardiography is mandatory. Treatment aims to restore a 'normal' blood pressure by fluid loading (with caution) and catecholamines and to drain the pericardium in emergency.Cardiac tamponade is responsible for an obstructive shock. Causes of pericardial effusion are numerous. Echocardiography is the fundamental tool for the diagnosis and therapeutic management. Volume resuscitation and catecholamines are temporary treatments, pericardial drainage remaining the only effective treatment.