Patient Care Technician (PCT) AAH Practice Exam

What is the speed of an EKG typically set to?

1. 10 mm/sec

2. 25 mm/sec

3. 50 mm/sec

4. 75 mm/sec

The correct answer is: 25 mm/sec

The appropriate speed setting for an electrocardiogram (EKG) is typically 25 mm/sec. This speed allows for a clear representation of the heart's electrical activity, making it easier for healthcare professionals to read and interpret the EKG strips. At this rate, each small square on the EKG graph paper represents 0.04 seconds, while each larger square (composed of five small squares) represents 0.20 seconds. This standardization helps in measuring intervals and segment lengths accurately, which is crucial for diagnosing various cardiac conditions. While lower speeds, such as 10 mm/sec, produce wider tracing that may not provide enough detail for accurate assessment, higher speeds, like 50 mm/sec or 75 mm/sec, can compress the waveforms and potentially obscure important information regarding the heart's rhythms. Therefore, 25 mm/sec is the established rate that balances clarity with the need for detail in EKG interpretation.