Shortness of breath occurs when the damage to the heart limits the output of the left ventricle, causing left ventricular failure and consequent pulmonary edema. Other symptoms include diaphoresis (an excessive form of sweating), weakness, light-headedness, nausea, vomiting, and palpitations. These symptoms are likely induced by a massive surge of catecholamines from the sympathetic nervous system, which occurs in response to pain and the blood flow abnormalities that result from dysfunction of the heart muscle. Loss of consciousness (due to inadequate blood flow to the brain and cardiogenic shock) and sudden death (frequently due to the development of ventricular fibrillation) can occur in MIs.