Which of the following is a sign that the AED is analyzing the heart rhythm?

The correct answer indicates that the Automated External Defibrillator (AED) is in the process of evaluating the heart’s rhythm. When the device displays "analyzing," it is actively assessing whether the heart rhythm is shockable or not. This crucial step is part of the AED's function to determine if a defibrillation shock is necessary to treat a serious heart rhythm issue like ventricular fibrillation or pulseless ventricular tachycardia.

The other choices reflect actions or indications that occur at different stages of using the AED. For instance, "shock advised" signals that the machine has completed its analysis and determined that a shock is needed. Beeping often serves as an alert or an instruction to the user, such as prompting them to stand clear, rather than indicating it is analyzing. Detecting a pulse would imply that the heart has returned to a stable rhythm, which is not a sign of the analysis phase but rather the outcome of effective intervention. Understanding these distinctions is vital for effective CPR and AED use.