Myocardial infarction, or heart attack, is the leading cause of death in adults in the world. It occurs when lack of circulation to part of the heart kills the cells in that area, thus ceasing heart function. Some people suffer several heart attacks in their lifetime that do not result in death. However, even one heart attack can kill a person. Immediate treatment of some heart attacks is necessary to stop the damage before it results in death. Even then, treatment is not always successful. As much as one quarter of heart attacks will not produce any symptoms, though this is more likely in women than in men. When there are symptoms, the most common are weakness, shortness of breath and sudden chest pain. The pain can radiate from the chest and into the left arm, shoulder and neck. Some other conditions can present with the same symptoms leading people to believe they are having a heart attack when it is something less urgent. Nonetheless, these symptoms should be treated as serious and heart attack should be ruled out. Other symptoms of heart attack are heart palpitations, vomiting, nausea, sweating, anxiety, heartburn and fatigue. Any or all of these symptoms may be present during a heart attack. While anxiety produces similar symptoms, heart attack should not be ruled out in the presence of anxiety. The symptoms of heart attack are more than capable of producing anxiety. One should never assume that these symptoms are anxiety, especially if there is a pre-existing heart condition. Several other potentially fatal events can present as a heart attack. These include fluid buildup around the heart, esophageal perforation, collapsed lung and pulmonary embolism. There are also non-life threatening illnesses that can produce heart attack symptoms, such as anxiety and acid reflux. Only a doctor can diagnose a heart attack, using a number of tests and patient history. A heart attack can also go completely unnoticed until those tests become necessary for another reason or another heart attack. If those tests never become necessary, the heart attack should be noted during autopsy whether or not it is the cause of death or occurred earlier.