Which statement best describes ventricular fibrillation on an ECG?

Which statement best describes ventricular fibrillation on an ECG?

• A. Irregular rhythm with no discernible P waves, QRS complexes or T waves; waveforms may vary in amplitude from coarse to fine and may progress to asystole.
• B. Regular rhythm with clearly defined P waves and QRS complexes.
• C. The ventricular rate is usually greater than 180 bpm and the QRS complexes are very wide.
• D. Flat baseline with no electrical activity on any lead.

Answer: (A)

Ventricular fibrillation is a chaotic, disorganized electrical activity in the ventricles that produces no coordinated contraction. On an ECG this shows up as an irregular, erratic baseline with no recognizable P waves, QRS complexes, or T waves. The waveforms can vary in amplitude, described as coarse when large and fine when small, and without organized depolarization there is no effective heartbeat. This erratic activity rapidly leads to loss of cardiac output, so it is a life-threatening rhythm that requires immediate defibrillation and high-quality CPR as part of ACLS. The other patterns describe different rhythms. A regular rhythm with clearly defined P waves and QRS complexes is an organized rhythm, not VF. A very fast ventricular rhythm with wide QRS suggests ventricular tachycardia, which is still organized conduction rather than the chaotic activity seen in VF. A flat baseline with no electrical activity is asystole, which is also non-perfusing but represents a different electrical state.

Ventricular fibrillation is a chaotic, disorganized electrical activity in the ventricles that produces no coordinated contraction. On an ECG this shows up as an irregular, erratic baseline with no recognizable P waves, QRS complexes, or T waves. The waveforms can vary in amplitude, described as coarse when large and fine when small, and without organized depolarization there is no effective heartbeat. This erratic activity rapidly leads to loss of cardiac output, so it is a life-threatening rhythm that requires immediate defibrillation and high-quality CPR as part of ACLS.

The other patterns describe different rhythms. A regular rhythm with clearly defined P waves and QRS complexes is an organized rhythm, not VF. A very fast ventricular rhythm with wide QRS suggests ventricular tachycardia, which is still organized conduction rather than the chaotic activity seen in VF. A flat baseline with no electrical activity is asystole, which is also non-perfusing but represents a different electrical state.