An electrocardiogram (ECG/EKG): a recording of the heart's electrical activity, used to check heart rhythm and detect abnormalities.
胸の痛みを訴えたので、病院で心電図を取った。
Because he complained of chest pain, they took an ECG at the hospital.
医師は心電図の波形を詳しく確認した。
The doctor examined the ECG waveforms in detail.