IPA: /ˌkɑːr.dɪ.əˈɡræf.ɪk/
KK: /kɑrdiəˈgræfɪk/
Relating to a device that records the electrical activity of the heart.
The cardiographic data showed a normal heartbeat pattern.
Cardiographic → It is formed from "cardio-" (from Greek "kardia", meaning heart) and "-graphic" (from Greek "graphia", meaning writing or recording). The word "cardiographic" refers to the recording or writing of heart activity.
Think of 'heart' ('cardio-') being 'recorded' ('-graphic') — that's what cardiographic means.