the branch of medicine that deals with diseases and abnormalities of the heart.

Cardiology (from Greek καρδίᾱ kardiā, "heart" and -λογία -logia, "study") is a branch of medicine dealing with disorders of the heart be it human or animal. The field includes medical diagnosis and treatment of congenital heart defects, coronary artery disease, heart failure, and valvular heart disease.

https://en.wikipedia.org/wiki/Cardiology