Under what condition does a junctional escape rhythm occur?

Under what condition does a junctional escape rhythm occur?

• A. When junctional automaticity foci are suppressed
• B. When the atrial automaticity foci stop functioning
• C. When the junctional foci are no longer suppressed by the atrial foci
• D. When the ventricular foci commence pacing

Answer: (C)

A junctional escape rhythm occurs when the atrial automaticity foci are no longer able to initiate impulses, allowing the junctional foci to take over pacing. In this situation, the heart's normal pacemaker, the sinoatrial (SA) node, is either not firing due to its failure or it has been overridden by another pathophysiological process. Consequently, the junctional area, which has inherent rhythmic pacing capabilities, becomes the primary pacemaker of the heart. This rhythm typically manifests with a heart rate of 40 to 60 beats per minute.

The selected answer reflects the correct underlying mechanism: it highlights the situation in which the junctional foci take control due to the suppression or inactivity of the atrial pacemaker, enabling the junctional escape rhythm to occur. This transition is crucial for maintaining some level of cardiac output in the absence of effective atrial activity.