Most patients with atrial fibrillation have a ventricular rate of 100-150 beats per minute, and those with a rate greater than 100 beats per minute are called tachyarrhythmic atrial fibrillation, and their ventricular rate can even exceed 150 beats per minute. Some patients even have atrial fibrillation combined with pre-excitation, and the ventricular rate can exceed 250 beats/min, which is very dangerous and can easily lead to ventricular fibrillation and cardiac arrest. Patients with atrial fibrillation can also have a slow ventricular rate, some less than 60 beats per minute, called slow atrial fibrillation. Whether it is fast or slow, it has an effect on the patient’s cardiac function, and it has an effect on the patient’s hemodynamics. So the ventricular rate in patients with atrial fibrillation is variable, but most people are in that range mentioned earlier.