Which device is commonly used to record an ECG?

The cardiac monitor is commonly used to record an electrocardiogram (ECG) because it is specifically designed to continuously observe and display the electrical activity of the heart. This device provides real-time monitoring, which is essential in clinical settings for diagnosing arrhythmias, evaluating heart conditions, and tracking the heart's rhythm during various medical situations, such as surgery or intensive care.

In contrast, an ultrasound machine is utilized for imaging soft tissues and assessing blood flow but does not measure electrical activity. An X-ray machine is used primarily for visualizing the structure of bones and certain tissues, not for recording heart rhythms. A blood pressure cuff measures blood pressure, which is a different physiological aspect and does not provide information on the heart's electrical patterns. This distinction highlights why the cardiac monitor is the most appropriate choice for ECG recording.