Some common sense you need to know about ECG paper
With the popularization of home electrocardiographs, self-testing of electrocardiograms at home anytime and anywhere is no longer out of reach.
So, how much do you know about some common sense about ECG measurement? Hurry up and take a look at the editor of a good friend ECG machine!
The most basic measurement parameters of the electrocardiogram include heart rate, P wave time, P-R interval, QRS time, Q-T interval, average ECG axis and so on.
1. What do the squares on the ECG drawing represent?
There are two thick and thin vertical and horizontal lines on the electrocardiogram recording paper.
The vertical line represents the voltage, expressed in mV, and can be expressed in mm under special circumstances.
The horizontal line represents time, expressed in s or ms.
Usually the paper speed of ECG recording is 25mm/s, so each small division represents 0.04s, and each large division (5 small divisions) represents 0.2s.
The calibration voltage is 10mm (10 small divisions) for 1mV, so each small division represents 0.1mV, and each large division represents 0.5mV.
Select the leads with clearer bands, and use the sub-gauge to measure.
When measuring the voltage of a positive wave, measure from the upper edge of the baseline to the highest point of the wave; when measuring a negative voltage, measure from the lower edge of the baseline to the lowest point of the wave.
The measurement time should be measured from the leading edge of a wave starting to the leading edge of the wave ending. In short, the influence of the baseline should be removed when measuring.