Stokes-Adams episodes are associated with syncope due to which mechanism?

• A. Atrial fibrillation with rapid rate
• B. Coronary artery vasospasm
• C. Atrial tachycardia
• D. Sudden AV bundle block leading to decreased cerebral perfusion

Answer: (D)

Stokes-Adams episodes happen when there is a sudden complete AV block that stops ventricular activity. That abrupt pause in the ventricles leads to a dramatic drop in cerebral blood flow, causing syncope. After a few seconds, an intrinsic escape rhythm often kicks in and consciousness returns. The transient asystole or severe bradycardia is what brings on the faint, and convulsions can occur from the temporary lack of blood to the brain. This mechanism—sudden AV bundle block causing decreased cerebral perfusion—is what explains the episodes. Other listed scenarios involve tachyarrhythmias or ischemia that provoke symptoms by different pathways, not the brief periods of abrupt bradycardia and asystole characteristic of Stokes-Adams.