Ventricular fibrillation is characterized by which description?

• A. The ventricles quiver with no effective contraction
• B. Regular, rapid ventricular contractions
• C. Slow, organized atrial activity
• D. Erratic, rapid and completely ineffective depolarization of the ventricles

Answer: (D)

Ventricular fibrillation is a chaotic, disorganized electrical activity in the ventricles that prevents coordinated depolarization and pumping. The best description captures this: erratic, rapid and completely ineffective depolarization of the ventricles. Because the electrical signals are chaotic, the ventricles quiver rather than contract in a synchronized way, so there is no effective cardiac output.

The other descriptions don’t fit as well: a ventricle quivering with no effective contraction does describe the outcome of VF, but it doesn’t emphasize the underlying chaotic electrical activity; a regular, rapid ventricular rhythm describes ventricular tachycardia, not VF; slow, organized atrial activity describes a different rhythm altogether. In practice, VF requires immediate defibrillation and CPR because the heart isn’t delivering blood flow.