What does a small grid on electrocardiogram paper represent？

The length and width of each small cell on the electrocardiogram paper are one millimeter, with horizontal lines representing time and vertical lines representing voltage.

Generally, the speed of paper feeding is 25 mm per second. Each cell on the horizontal line represents 0.04 seconds, and a cell on the vertical line represents 0.1 millivolts.

Electrocardiogram is the standard for detecting arrhythmia diseases, which include atrial tachycardia, ventricular tachycardia, supraventricular tachycardia, preexcitation syndrome, etc. Electrocardiogram is also used for physical examination of various populations.

When patients undergo an electrocardiogram examination, their emotions and surrounding environment should be kept quiet and stable. It is also necessary to fully expose their wrists, ankles, or chest, while avoiding speech. If the patient is too thin, coupling agents or oils can be applied to the chest.

For ordinary patients, local wetting with water is sufficient. If an electrocardiogram test has been performed before, a previous electrocardiogram test report should be brought for comparison before and after. If a patient takes excessive medication that may affect their heart rate or electrocardiogram, they should inform the doctor of the medication used and its dosage to avoid misdiagnosis. It is also necessary to avoid consuming spicy, stimulating, or greasy foods, such as chili peppers, Chinese prickly ash, or fatty meat, before the inspection.