Which term describes atrial fibrillation, characterized by chaotic electrical activity in the atria?

• A. Aneurysm
• B. S1S2
• C. A fib
• D. AAA

Answer: (C)

Atrial fibrillation is defined by chaotic electrical activity in the atria, which causes the atria to quiver rather than contract in a coordinated way. On ECG this appears as a lack of distinct P waves with an irregularly irregular ventricular rhythm due to variable conduction. The term that matches this description is atrial fibrillation, often abbreviated as A fib, so it’s the best choice. The other terms describe different things—an aneurysm is a bulge in a vessel wall; S1S2 refers to the heart sounds; and an abdominal aortic aneurysm is an aneurysm of the abdominal aorta—none of which describe chaotic atrial electrical activity.