What are the elements of the electrocardiography (ECG) grid?

Updated: Mar 11, 2019
  • Author: Tarek Ajam, MD, MS; Chief Editor: Terrence X O'Brien, MD, MS, FACC  more...
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Answer

Answer

In the image below, the ECG is recorded on standard paper with large boxes in heavy lines of 0.5 cm on the sides. On the horizontal axis, each large box represents 0.2 seconds at a typical paper speed of 25 mm per second, which is then divided into five smaller boxes that each represent 0.04 seconds. On the vertical axis, the large box consists of five subdivisions, each of which is 1 mm in height. In standard calibration, each 10 mm equals 1 mV.  The normal heart rate ranges from 60 to 100 per minute; rates below 60 per minute and, occasionally, lower than 50 per minute are routinely seen in seasoned athletes.

On standard calibration, each large box has sides On standard calibration, each large box has sides of 0.5 cm. On the horizontal axis, each large box represents 0.2 seconds, and each smaller box represents 0.04 seconds. On the vertical axis, each small box is 1 mm in height; 10 mm = 1 mV.

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