Define "ventricular fibrillation" and its ECG appearance.

• A. Ordered electrical activity with consistent QRS complexes
• B. Chaotic electrical activity of the ventricles with no identifiable waves
• C. Slow, regular beats with inverted T waves
• D. Rapid ventricular contractions with distinct P waves

Answer: (B)

Ventricular fibrillation is a life-threatening arrhythmia characterized by chaotic electrical activity in the ventricles. This disorganized state prevents the heart from effectively pumping blood, leading to loss of consciousness and, if not treated promptly, can result in death.

On an ECG, ventricular fibrillation is marked by a complete absence of identifiable waves, including QRS complexes, P waves, and T waves. Instead, the tracing appears as rapid, random fluctuations of amplitude and frequency, resembling a "zigzag" pattern. This chaotic electrical activity indicates that the ventricles are quivering rather than contracting efficiently, which is why option B accurately describes both the condition and its ECG appearance.

The other descriptions do not align with the nature of ventricular fibrillation; they refer to organized electrical activities or rhythms that are recognizable, which are not present in this serious arrhythmia.