Clinical Analysis of 126 Cases of Postoperative Arrhythmia in Esophageal and Cardiac Surgery: The incidence rate was 2.65% (3/13) for cardiac surgery, and 22.8% (119/539) for esophageal cancer surgery. The difference was significant (P < 0.01). When arrhythmia occurs, timely management can more quickly correct it. Due to the continuous improvement of medical equipment, thoracotomy patients’ ECG has become a routine observation for arrhythmias, as well as their causes and adverse effects, which are gradually receiving attention. Arrhythmia can affect cardiac output and cause hypoperfusion of important organs. Serious arrhythmias may lead to sudden death and should be detected and managed correctly. There are many reasons causing arrhythmia, including anesthesia, surgical stimulation, oxygen deficiency, acidosis, blood pressure being too low or too high, surgical trauma, and procedures that stimulate factors causing arrhythmias. Anesthesia should be smooth with full oxygenation. The surgical procedure should be gentle, minimizing the traction of lung tissue and the compression of the heart. After the surgery ends, airway secretions should be thoroughly absorbed to maintain airway patency. Accurate records of postoperative decompression and closed thoracic drainage should be kept. Timely fluid transfusion is necessary to prevent hypovolemia and electrolyte imbalance. Vagotomy increases sympathetic tone, and postoperative arrhythmia is directly related to this. This group had a lower incidence of arrhythmia after cardia surgery compared to esophagectomy. It proves that postoperative pain cannot be ignored as a cause of arrhythmia. Pain makes patients irritable, anxious, and even fearful, increasing catecholamines and angiotensin, inducing myocardial self-regulation and stress enhancement, making arrhythmias prone to occur. In this group, 98.4% of arrhythmias occurred within 72 hours after the operation, which is also the peak period of postoperative pain. Therefore, choosing an appropriate sedative for pain relief is necessary recently. During the operation, corresponding parts of the spine can be incised with epidural catheterization, and then a pain pump can be retained postoperatively, achieving satisfactory results. The effectiveness of preventing and treating cardiovascular complications is significant. The average age was 61.5 years, which is a relevant factor in the elderly population itself being prone to arrhythmia. Early postoperative blood viscosity in the elderly significantly increases, coupled with more atherosclerosis, diminishing cardiovascular strain capacity. Postoperative arrhythmia is an important reason. Equal amounts of intraoperative blood transfusion, an appropriate amount of expansion, and the application of some low molecular weight dextran and other treatments help prevent arrhythmia to some extent.