Which one of the following is not a sign of cardiac arrest?

In the context of identifying signs of cardiac arrest, the correct choice is based on understanding the typical symptoms associated with this medical emergency. Cardiac arrest is characterized by the heart's inability to pump blood effectively, which leads to a lack of blood flow to vital organs, most notably the brain.

Unconsciousness and not breathing are direct indicators of cardiac arrest; when the heart stops functioning, it often results in the loss of consciousness and the cessation of breathing. Unusual breathing can also signify an imminent cardiac arrest situation, as the body struggles to get oxygen, leading to abnormal respiratory patterns.

On the other hand, pain in the arms is not a definitive sign of cardiac arrest. While it might be associated with other heart-related issues, such as a heart attack, it is not a specific sign indicating that the heart has stopped beating. Therefore, it does not fit with the acute and critical symptoms directly associated with cardiac arrest, making it the correct answer to the question.