Which statement about complete heart block is true?

• A. In complete heart block, there is complete coordination between atrial and ventricular activity
• B. In complete heart block, there is no coordination between atrial and ventricular activity
• C. The ventricles pace in synchrony with the atria
• D. Defibrillation is routinely used to treat complete heart block

Answer: (B)

Complete heart block means the atrial and ventricular rhythms are independent because the impulse from the atria cannot reach the ventricles. P waves keep their own regular rhythm, while the ventricles contract on their own slower “escape” rhythm below the block. This AV dissociation means there is no coordinated timing between atrial and ventricular activity, which is exactly what the statement describes. In practice, this dissociation is why patients may become symptomatic from bradycardia and often require pacing (temporary or permanent) rather than shocks. Defibrillation is not a routine treatment for CHB; it is used for pulseless tachyarrhythmias like ventricular fibrillation or pulseless VT, not for heart block.