'cardiological' originates from Greek, specifically the word 'kardia', where 'kardia' meant 'heart'; it entered scientific Latin as 'cardiologia' ('study of the heart') and in English formed from 'cardiology' + the adjectival suffix '-ical'.

'cardiological' changed from New Latin 'cardiologia' and the modern English noun 'cardiology' and eventually became the adjective 'cardiological' in English usage.

Initially it was built on a root meaning 'heart' (and 'study of the heart' for 'cardiologia'), but over time it evolved into its current meaning of 'relating to the heart or the medical specialty dealing with the heart.'