On EKG paper, what distance represents one second?

The correct answer is that one second on EKG paper is represented by 5 large squares. Each large square on standard EKG paper is composed of 5 small squares. The standard speed of the EKG paper is 25 mm per second, and since one large square measures 5 mm in width, it takes 5 large squares to cover a duration of 5 seconds (5 large squares x 5 mm = 25 mm). Therefore, this distance correlates directly to one second of time on the recording.

Understanding this metric is crucial for interpreting EKGs, as it allows healthcare professionals to measure intervals, rhythms, and other critical aspects of cardiac function accurately. Knowing that 5 large squares equal one second helps in calculating heart rates, determining the duration of different segments and intervals, and assessing any potential abnormalities present in the heart’s electrical activity.