What does a 12 lead EKG trace?

A 12 lead EKG (electrocardiogram) is specifically designed to measure and display the electrical activity of the heart. It captures how electrical impulses spread through the heart muscle during each heartbeat, providing critical information about the heart's rhythm, size, and position of the heart chambers. This data is vital for diagnosing a range of cardiac conditions, such as arrhythmias, heart attacks, and other heart diseases.

In contrast, the other choices focus on different physiological parameters. Blood pressure levels are measured using a sphygmomanometer, not an EKG. Oxygen saturation refers to the amount of oxygen carried by hemoglobin in the blood, typically assessed by a pulse oximeter. The respiratory rate measures how often a person breathes in a minute and is usually monitored through observation or a respiratory monitor, rather than through electrical activity. Thus, understanding the primary function of a 12 lead EKG as an instrument for monitoring the heart's electrical activity is essential for anyone in the medical field.