An automaticity focus is considered overdrive suppressed when:

An automaticity focus is considered overdrive suppressed when:

• A. Paced regularly at its inherent rate
• B. Paced at a rate slower than its inherent rate
• C. Paced faster than its inherent rate
• D. It ceases to activate

Answer: (C)

An automaticity focus is considered overdrive suppressed when it is paced faster than its inherent rate. This phenomenon occurs because an automaticity focus generates a certain inherent intrinsic rate, which is determined by the speed at which it depolarizes and can produce spontaneous action potentials.

When the automaticity focus is stimulated at a rate that is faster than its inherent rate, it effectively leads to suppression of the focus due to the principle of overdrive suppression. This means that, under faster pacing conditions, the automaticity focus is unable to initiate its own impulses because it is being overridden by the faster, competing electrical activity. Overdrive suppression is a protective mechanism that ensures that the heart rhythm is maintained in a more organized manner, prioritizing the faster pacemaker activity.

Thus, when the automaticity focus is paced faster than itself, it remains inactive and does not produce impulses, confirming it is in a state of overdrive suppression.