Final answer:
In a case of cardiac arrest with asystole, the main intervention besides CPR is the use of an AED, if a shockable rhythm is present. Amiodarone is not indicated for asystole, and CPR should be continued with other ACLS measures like epinephrine administration.
Step-by-step explanation:
When a patient is experiencing a cardiac arrest and the cardiac monitor shows asystole, the priority intervention, in addition to continuous high-quality CPR, is to use an automated external defibrillator (AED) if available. Amiodarone would not be effective in a flatlined heart, because it's an antiarrhythmic medication best used for shockable rhythms like ventricular fibrillation or ventricular tachycardia.
For asystole or a non-pumping heart, the focus is on CPR and potential administration of epinephrine as per Advanced Cardiac Life Support (ACLS) guidelines. The AED analyzes the heart's rhythm and, if a shockable rhythm is detected, delivers an electrical shock in an effort to reset the heart's natural pacemaker and restore a normal rhythm. However, as asystole is a non-shockable rhythm, the AED would not advise a shock and CPR should be continued with any available advanced life support measures.