Cardiology is the branch of medicine dedicated to the study and treatment of the heart and cardiovascular system, covering conditions like coronary artery disease, heart failure, and arrhythmias. While cardiologists are physicians who diagnose and manage these disorders, they are distinct from cardiothoracic surgeons, who perform major operations like bypass surgery—though cardiologists now increasingly handle less invasive procedures such as cardiac catheterization, transcatheter aortic valve implantation (TAVR), and pacemaker insertions. Becoming a cardiologist requires extensive training: in the US, this means a three-year internal medicine residency followed by a three-year cardiology fellowship, while in the UK, doctors complete foundation and internal medicine training before a five-year specialty program. Cardiologists can further sub-specialize in areas like interventional cardiology, electrophysiology, heart failure, and adult congenital heart disease. A crucial distinction is that adult and pediatric cardiology require separate training pathways, so an adult cardiologist is not qualified to treat children, and vice versa. This field blends deep medical expertise with advanced procedural skills to address the heart's complex disorders.