The speed of the heartbeat, also known as the heart rate (number of heartbeats per minute), can be calculated very quickly in an ECG. Overall, the closer the waveforms of an ECG are to each other, the faster the heart rate is; conversely, the farther away they are, the slower it is (the top left image below is the slowest, the top right image is the fastest, the bottom left image is the second fastest, and the bottom right image is the third fastest heart rate). Second, for beginners, you can look at the speed of the heart rate can be, mainly through the distance between the two waveforms to analyze: when the distance between the two waveforms for a large square so wide, at this time the heart rate of 300 times / min; the distance of 2 large squares when the heart rate of 150 times / min; the distance of 3 large squares when the heart rate of 100 / min; the distance of 4 large squares when the heart rate of 75 / min; the distance of 5 large squares when the heart rate of 75 / min; the distance of 5 large squares when the heart rate of 100 / min; the heart rate of 75 / min; the heart rate of 75 / min; the distance of 5 large squares when the heart rate of 75 / min; the heart rate of 75 / min. The heart rate is 60 beats/min when the distance is 5 large squares, and 50 beats/min when the distance is 6 large squares. Generally, you can get a good idea of how fast your heart rate is by using this method. Third, on the ECG, it is sometimes necessary to measure two sets of heart rate, namely, the speed of the atrial beats (due to atrial power generation to form the P wave, so we have to measure the distance between the P wave to determine), and the speed of the ventricular beats (ventricular power generation to form the QRS wave group, so we have to measure the distance between the QRS wave group to determine). The former is called the atrial rate and the latter is called the ventricular rate. Why measure 2 sets of heart rates? Because some arrhythmias can cause the disappearance of certain P waves or QRS wave clusters, resulting in an unequal number of both, so when the number of P waves and QRS wave clusters are unequal, the atrial rate and ventricular rate should be calculated separately. Fourth, if you encounter a particularly obvious irregular ECG, you should measure the total length between 5-10 waveforms consecutively, and then divide the value of the total length by 5-10 to get the average value of the heart rate.