What is an electrocardiogram?

An electrocardiogram is specifically defined as a recording or tracing of the electrical activity of the heart over a period of time. It is performed using electrodes placed on the skin, which detect the electrical signals produced by heartbeats. This information is plotted on graph paper or displayed on a monitor, allowing healthcare professionals to assess the heart’s rhythm, rate, and electrical activity.

The other options do not accurately describe what an electrocardiogram is. For instance, heart surgery refers to invasive procedures aimed at treating heart problems, and a device that monitors heart rate usually refers to equipment like a pulse oximeter or a heart rate monitor, which may not record the electrical activity as an EKG does. Lastly, a chemical used to treat heart conditions would typically refer to medications, which are not involved in the recording process that defines an electrocardiogram. Hence, the definition of an electrocardiogram as a recording or tracing of the heart's electrical activity is both precise and comprehensive.