Atrial fibrillation is primarily caused by?

Atrial fibrillation is primarily caused by?

• A. Single focus in the atria
• B. Multiple irritable automaticity foci in the atria
• C. Blockage in the coronary arteries
• D. Overactive vagus nerve

Answer: (B)

Atrial fibrillation is characterized by disorganized electrical signals in the atria, leading to an irregular and often rapid heart rate. The primary cause of atrial fibrillation is the presence of multiple irritable automaticity foci within the atria. These foci arise due to different factors, such as structural changes in the heart tissue, which can lead to uncoordinated contractions and ineffective atrial pumping.

When there are multiple ectopic foci in the atria, they can fire off electrical impulses independently. This results in a chaotic and rapid activation of the atria, preventing coordinated contractions and contributing to the hallmark irregular rhythm of atrial fibrillation. The condition can be further exacerbated by factors such as hypertension, heart failure, and valvular heart disease.

In contrast, other options like a single focus or blockage in coronary arteries don’t account for the chaotic nature of atrial fibrillation effectively. While vagal influence can affect heart rate and rhythm, it is not the primary cause of the electrical disturbance seen in atrial fibrillation itself. Thus, understanding the role of multiple irritable automaticity foci provides insight into the mechanism behind atrial fibrillation.