Which test records the heart’s electrical activity?

• A. Epiglottis
• B. Electrocardiogram (EKG)
• C. Duodenum
• D. Echocardiogram (Echo)

Answer: (B)

The electrocardiogram records the heart’s electrical activity. It detects the electrical impulses that coordinate each heartbeat and outputs a tracing showing rhythm, rate, and timing of electrical events (like atrial and ventricular depolarization and repolarization) through electrodes placed on the body. This is different from tests that image anatomy or function: an echocardiogram uses ultrasound to visualize heart structure and motion, while the other options relate to parts of the digestive or airway systems (epiglottis and duodenum) and do not measure electrical activity.