A Holter monitor is best described as a portable device that:

• A. Records the heart's electrical activity continuously for 24-48 hours
• B. Measures blood pressure every hour
• C. Monitors oxygen saturation at rest
• D. Records body temperature

Answer: (A)

A Holter monitor is used to capture the heart’s electrical activity over an extended period while you go about daily life. It continuously records the rhythm for about 24 to 48 hours, which lets clinicians detect intermittent arrhythmias or rhythm problems that a single short ECG might miss. The device is worn on the chest with electrodes, and you typically keep a diary of symptoms and activities so the data can be correlated with what you felt or did. After the monitoring period, the data are reviewed to identify any abnormal rhythms or events. It does not measure blood pressure, oxygen saturation, or body temperature, which is why those options aren’t describing a Holter monitor.