cardiology
Medical specialty dealing with heart diseases. Used in academic and clinical contexts.
See also: 循環器科
He is a specialist in cardiology.
I am reading a textbook on cardiology.
循環器科 is the clinical department of cardiovascular medicine, while 心臓病学 is the academic discipline of cardiology.
Compound of 心臓 (heart) + 病 (disease) + 学 (study). A straightforward modern medical term.