The principal consultant in diseases of the heart and some disorders of blood circulation is the cardiologist. Apart from being an expert interpreter of heart murmurs and other sounds through the stethoscope, there are some other important methods of investigation open to him. The electrocardiogram is paramount in establishing the degree and location of disorders, and the echocardiogram is also an important tool. With cardiac catheterization blood flow and pressure in the heart can be measured, and angiography discloses any narrowing of the blood vessels that is present. Blood tests will reveal the amount of cardiac enzymes that are present in cases of infarction, and so on. The cardiac surgeon is a superspecialist dealing with all kinds of operations concerning the heart. These will range from inserting pacemakers to replacing damaged valves and bypass operations. Heart transplants are not within the capabilities of the average cardiac surgeon.
Another specialist whose field is closely related to that of cardiology is the haematologist. This specialist knows all about diseases of the blood and bone marrow and how to interpret the information obtained from blood tests.