Cardiology is one of the medications associated with heart problems and the circulatory system. Among the areas involved include medical diagnosis and congenital heart defect control, coronary artery disease, heart failure, heart valve disease and electrophysiology. Cardiologists who are experts in cardiology are called as cardiologists, who have expertise in internal medicine. Children's cardiology is a pediatrician specializing in cardiology. Doctors specializing in cardiac surgery are called cardiothoracic surgeons while doctors who are experts in general surgery are heart or cardiac surgeons. Although the cardiovascular system is closely related to the blood, cardiology is somewhat irrelevant to hematology and its disease. Some exceptions that affect heart function are blood tests (electrolyte disorders, troponin), lower oxygen carrying capacity (anemia, hypovolemic shock), and coagulopathy.