Cardiology is a medical specialty dealing with disorders of the heart. The field includes diagnosis and treatment of congenital heart defects, coronary artery disease, heart failure, valvular heart disease and electrophysiology. Physicians specializing in this field of medicine are called cardiologists. Cardiologists should not be confused with cardiac surgeons, cardiothoracic and cardiovascular, who are surgeons who perform cardiac surgery via sternotomy - open operative procedures on the heart and great vessels.