For which conditions is defibrillation used?

Defibrillation is specifically used for life-threatening cardiac rhythms, most notably ventricular fibrillation and pulseless electrical activity, as well as during cardiac arrest situations. These conditions are characterized by the heart not maintaining effective circulation due to chaotic electrical activity, which can lead to sudden death if not treated immediately.

In the case of ventricular fibrillation, the heart's electrical activity becomes disorganized, preventing effective pumping of blood. Defibrillation delivers a controlled electrical shock to the heart, restoring a normal rhythm and allowing the heart to pump blood effectively again. This intervention is crucial in emergency situations, as it can significantly increase the chances of survival and recovery.

In contrast, the other choices reflect conditions that either do not require immediate defibrillation or involve less acute rhythms. Frequent atrial fibrillation, chronic heart murmurs, and stable bradycardia do not typically result in life-threatening situations that warrant the use of a defibrillator.