A cardiac surgeon is a medical professional who is experienced and skilled in treating heart problems, disorders, diseases, and conditions. They can diagnose certain heart problems and treat them with surgery. They work closely with other medical professionals, such as primary care doctors and cardiologists. Cardiac surgeons often perform surgeries to correct heart problems and heart disease, but they can also work on other areas in the chest.

Critical care is provided for patients who are suffering from life-threatening conditions. The doctors who work with these people are often called intensivists. They focus on a range of different issues, so they can serve people who need immediate and life-saving care. Since people who need critical care are suffering from such a wide variety of issues, intensivists must have a thorough understanding of diverse types of medical issues and the devices and medications needed to treat them.

An internist or Internal Medicine doctor is someone who specializes in diagnosing and treating illnesses, diseases, and health problems. Most internists are also primary care doctors and treat patients on a regular basis. They can diagnose and treat common illnesses or more serious problems. Most people see an internist regularly. Those with chronic illnesses may do so on a monthly or even weekly basis. Internists are the most common types of doctors.