Table Mechanisms of Cardiogenic and Obstructive Shock Type Mechanism Cause Obstructive Mechanical interference with ventricular filling Tension pneumothorax, cava compression, cardiac tamponade, atrial tumor or clot Interference with ventricular emptying Pulmonary embolism Cardiogenic Impaired myocardial contractility Myocardial ischemia or myocardial infarction, myocarditis, drugs Abnormalities of cardiac rhythm Tachycardia, bradycardia Cardiac structural disorder Acute mitral or aortic regurgitation, ruptured interventricular septum, prosthetic valve malfunction Symptoms and Signs of Shock Altered mental status (eg, lethargy, confusion, somnolence) is a common sign of shock.