Cardiothoracic surgery (also known as thoracic surgery) is the field of medicine involved in surgical treatment of organs inside the thorax (the chest)—generally treatment of conditions of the heart (heart disease) and lungs (lung disease). In most countries, cardiac surgery (involving the heart and the great vessels) and general thoracic surgery (involving the lungs, esophagus, thymus, etc.) are separate surgical specialties; the exceptions are the United States, Australia, New Zealand, and some EU countries, such as the United Kingdom and Portugal.

What is the difference between cardiovascular and thoracic surgery? Cardiac or cardiovascular surgery focuses on the heart and great vessels. General thoracic surgery treats diseases of the lungs, esophagus, chest wall, and mediastinum. Congenital heart surgery focuses on infants and children with heart disease.