A patient visited a gastroenterologist for heartburn and acid reflux in the upper abdomen and was confused about all the tests the gastroenterologist ordered from the cardiology department, did the doctor intentionally order more tests or was there another reason? The patient asked the gastroenterologist, and this is my answer. In the structure of the human body, the cardia is connected to the lower part of the esophagus, immediately in front of the heart. Any experienced internist should pay equal attention to both diseases. Because the visceral nervous system is different from that of the skin, the sensations of the viscera will not be as precise in location and nature as those of the skin, and the viscera are not sick wherever they hurt. For example, cholecystitis often appears as pain at a point in the right back; pancreatitis often has back pain; angina often manifests itself in the left upper limb, left shoulder, left neck, and in some cases even as a toothache on the left side. So is heartburn burning the esophagus and cardia, or is it burning the heart? Doctors can only identify these two diseases by checking ECG, cardiac enzymes, cardiac ultrasound and even coronary angiography. No doctor can be 100% sure of the difference between heart disease and stomach disease. It may seem incomprehensible for a patient to go through multiple tests before being diagnosed with reflux esophagitis, and to go through many detours and spend a lot of money before finally being diagnosed with a disease that is not very fatal, but please understand the caution of every gastroenterologist.