Fibrillation on ECG is characterized by which description?

• A. A rapid, irregular and unsynchronized heartbeat.
• B. A regular fast rhythm.
• C. A slow and regular rhythm.
• D. A skipped beat sensation.

Answer: (A)

Fibrillation means rapid but uncoordinated electrical activity of the heart, so the heart quivers instead of contracting in a synchronized way. On ECG this shows up as a very fast rate with an irregular, chaotic pattern and no organized rhythm. You won’t see clear, regular P waves followed by consistent QRS complexes; the signal is chaotic, especially in ventricular fibrillation, which is life-threatening and requires immediate intervention. This description—rapid, irregular and unsynchronized heartbeat—best captures what fibrillation looks like on ECG. The other phrases describe things like a regular fast rhythm (tachycardia or flutter), a slow regular rhythm (bradycardia), or a sensation of skipped beats (ectopic beats or PACs), which are not fibrillation.