What can cause a ventricular escape rhythm to occur?

What can cause a ventricular escape rhythm to occur?

• A. Complete failure of the SA node alone
• B. High block in the ventricular conduction system
• C. AV node malfunction
• D. Damage to the atrial walls

Answer: (B)

A ventricular escape rhythm can occur primarily when there is complete failure of the heart's primary pacemaker, the sinoatrial (SA) node, leading to reliance on the intrinsic pacing ability of the ventricles—typically the Purkinje fibers or a foci in the ventricles themselves. In this specific scenario, a high block within the ventricular conduction system may also contribute to the maintenance of ventricular contractions by triggering an escape rhythm.

This rhythm commonly emerges when there is an interruption in the conduction pathways or alternative pacemaker activity becomes prominent due to failure of higher-level pacemaking. When the SA node's pacing is compromised, the ventricles can initiate beats to maintain a heart rate, thereby preventing prolonged asystole.

While other options may involve issues related to heart conduction, they either focus on different areas of the cardiac conduction system or do not directly result in a ventricular escape rhythm. The high block in the ventricular conduction path is significant because it allows the ventricles to take over pacemaking duties, thus enabling the escape rhythm to emerge in response to the failure of more proximal electrical conduction pathways.