What is the primary cause of atrial fibrillation?

What is the primary cause of atrial fibrillation?

• A. Single focus providing impulses
• B. Continuous rapid firing of multiple atrial automaticity foci
• C. Complete depolarization of the atria
• D. Regular sinus rhythm

Answer: (B)

The primary cause of atrial fibrillation is the continuous rapid firing of multiple atrial automaticity foci. In atrial fibrillation, the normal electrical impulses that control the heartbeat are disrupted, leading to chaotic electrical activity in the atria. This results in irregular and often rapid heartbeats.

The multiple automaticity foci refer to different points in the atrial tissue that can generate electrical impulses independently. These foci fire rapidly and unpredictably, leading to disorganized atrial contraction, which is characteristic of atrial fibrillation. This chaotic electrical activity causes the atria to quiver instead of contracting effectively, allowing blood to pool and increasing the risk of clot formation.

Other options do not represent the primary mechanism. The notion of a single focus providing impulses does not account for the irregular and multifocal nature of atrial fibrillation. Complete depolarization of the atria does not fit the pathophysiology since atrial fibrillation features chaotic activity rather than uniform depolarization. Finally, regular sinus rhythm signifies a normal rhythmic heartbeat, which is contrary to the definition of atrial fibrillation. Understanding these mechanisms is crucial for identifying and managing atrial fibrillation effectively in clinical practice.