Which term refers to a device that records the electrical activity of the heart over time?

• A. Electrocardiogram
• B. Swan-Ganz catheter
• C. Endotracheal tube
• D. Nasogastric tube

Answer: (A)

Recording the heart's electrical activity over time is accomplished with an electrocardiogram. An electrocardiogram, or ECG, uses leads placed on the skin to capture the heart’s electrical signals as it beats, producing a tracing that shows P waves, QRS complexes, and T waves. This allows detection of heart rate and rhythm, conduction abnormalities, and signs of ischemia or infarction. The other devices have different roles: a Swan-Ganz catheter measures pressures and cardiac output in the heart and lungs, an endotracheal tube secures the airway, and a nasogastric tube accesses the stomach. None of these primarily record the heart’s electrical activity.