A cardiothoracic surgeon is a medical doctor who specializes in surgeries involving the heart, lungs, and other organs in the chest. They perform complex procedures such as heart bypass surgery, valve repair, and lung resections. These surgeons undergo extensive training, including medical school and several years of residency in general surgery and cardiothoracic surgery. In addition to performing surgeries, cardiothoracic surgeons also diagnose and treat conditions related to the heart and chest. They work closely with other healthcare professionals, including cardiologists and pulmonologists, to provide comprehensive care for patients with serious health issues.