Which mechanism is most commonly associated with initiating atrial fibrillation (AF)?

The mechanism most commonly associated with initiating atrial fibrillation (AF) is focal tachycardia triggers. This refers to certain localized areas in the atria, such as the pulmonary veins, which can generate rapid electrical impulses that trigger episodes of AF. This initiation occurs when these ectopic foci produce disorganized electrical activity that overwhelms the atrial tissue, leading to the characteristic quivering of the atria seen in AF.

In many cases, ectopic foci, particularly from the left atrial pulmonary veins, are responsible for the onset of AF. Understanding this mechanism is crucial for developing effective treatment strategies, such as catheter ablation, which targets these specific sources of electrical activity to restore normal rhythm.

The other concepts mentioned, while related to AF, do not specifically mark the initiation as effectively as focal tachycardia triggers. For example, localized source and multiple wave reentry hypotheses describe how AF may maintain itself rather than its initiation. Non-PV triggers can also contribute but are less commonly recognized as the primary initiators in the majority of AF cases.