A typical acute heart attack will cause most people to be alerted, but there are four types of acute heart attack patients in daily life that do not present with acute and severe pain in the retrosternal or precordial regions and are easily overlooked. One is that about 30% of acute heart attack patients present with gastrointestinal symptoms, which are manifested as abdominal flatulence, eructation, abdominal pain, nausea, vomiting and diarrhea, and are often thought to be indigestion and acute gastroenteritis. When patients have severe abdominal pain, they often consult surgery and miss treatment. These symptoms may occur because the heart lesion irritates the vagus nerve, or the lesion is in the lower wall of the heart, or because the mesenteric artery is undersupplied with blood, causing gastrointestinal reactions. Secondly, patients mainly have respiratory symptoms, mostly cough and shortness of breath; some only feel tightness in the chest, breath-holding, or think they do not have enough air. If the patient has pre-existing chronic bronchitis, it is easy to be misdiagnosed as pulmonary heart disease. The mechanism of symptom occurrence is that in acute heart attack, the contractility of the heart muscle decreases and the volume of cardiac blood excretion decreases, causing pulmonary stasis, which is easily complicated by bronchial infection. Thirdly, patients develop psychoneurological symptoms: they show sudden slurred speech, paralysis of one side of the limb, unconsciousness and convulsions, which are easily confused with acute cerebrovascular disease; some patients show pain in the pharynx, jaw, neck, shoulder, occiput, forehead and waist in addition to pain behind the sternum. The mechanism of symptom occurrence is that in acute heart attack, the cardiac blood expulsion drops sharply, resulting in insufficient blood supply to the brain, especially in elderly people with pre-existing cerebral arteriosclerosis, who are more prone to cerebral circulation disorders; in addition, in acute heart attack, acidic metabolites stimulate sympathetic afferent fibers to produce nociception, and can radiate to any part of the cervical and thoracic spinal nerve innervation. Therefore, the above pain and discomfort should not be treated as pharyngitis, dental disease, cervical spondylosis, frozen shoulder, or vascular headache and neglected. When the above-mentioned pain and discomfort occur in the elderly and are accompanied by panic and sweating, they should promptly consult an electrocardiogram and measure serum enzymes for early diagnosis and treatment.