ECG stands for Electrocardiogram.
It is a diagnostic tool that records the electrical activity of the heart over a period of time using electrodes placed on the skin.
The purpose of ECG is to detect cardiac abnormalities such as arrhythmias, myocardial infarction, and other heart conditions.
EEG is for brain activity, EOG is for eye movements, and EMG measures muscle activity.
Thus, only ECG is the correct choice for recording heart-related electrical activity.