cardiology
branch of medicine dealing with disorders of the heart as well as parts of the circulatory system
interventional cardiology
branch of cardiology that deals specifically with the catheter based treatment of structural heart diseases
cardiac electrophysiology
science of elucidating, diagnosing and treating the electrical activities of the heart
cardiovascular physiology
study of the circulatory system, specifically addressing the physiology of the heart ("cardio") and blood vessels ("vascular")