Which term describes the test that records the heart's electrical activity?

• A. Tachypnea
• B. Peripheral edema
• C. Hematuria
• D. Electrocardiogram

Answer: (D)

The test that records the heart's electrical activity is an electrocardiogram. The heart generates electrical impulses as it beats, and an electrocardiogram uses skin-surface electrodes to detect these tiny voltage changes. The tracing shows the sequence of electrical events that coordinate the heartbeat, typically described by waves and intervals: P wave for atrial depolarization, the QRS complex for ventricular depolarization, and the T wave for ventricular repolarization. Clinically, this test helps assess heart rate, rhythm, and can reveal issues like arrhythmias or signs of ischemia or damage. The other terms aren’t tests of electrical activity: tachypnea means rapid breathing, peripheral edema is swelling from fluid buildup, and hematuria is blood in the urine.