Atrial fibrillation is a very common arrhythmia, affecting hundreds of millions of people worldwide. The diagnosis of atrial fibrillation is of great importance, as the timely initiation of oral anticoagulation can in many cases significantly reduce the risk of embolism (which is associated with this arrhythmia).
The risk of cardiac embolism is particularly high in the presence of paroxysmal atrial fibrillation, in which there is frequent alternation between sinus rhythm and atrial fibrillation.
Such a sequence is recorded here in a 3-lead ECG.