'cardiologic' originates from Greek via New Latin, specifically from the Greek root 'kardia' meaning 'heart' combined with the combining form '-logy' (from Greek 'logia') meaning 'study' and the adjective-forming suffix '-ic'.

'cardio-' + '-logy' entered English from New Latin/Greek as 'cardiology' (the study of the heart); the adjective form 'cardiologic' (and the variant 'cardiological') developed in English from these elements.

Initially it denoted 'pertaining to the study of the heart'; over time it came to be used more broadly as 'relating to the heart or heart diseases'.