What Is an Electrocardiogram?

By jolene

Article Sources

Medical Expert

More About Us

9. Grids

The ECG is recorded on paper with grids measuring 0.5 centimeters on the sides. Horizontally, each large box is equivalent to 0.2 seconds at a typical paper speed of 25 millimeters per second. Each large box is divided into 5 smaller boxes representing 0.04 seconds each. Vertically, each large box is equivalent to 0.5 mV (5 mm in height). In a normal individual, the heart rate ranges from 60 to 100 beats per minute with lower (normal) rates in athletes. Grids are used in an ECG tracing to help operators and clinicians read the ECG tracing better as it provides measurements.