Which rhythm indicates a patient is in need of defibrillation?

Ventricular fibrillation is a chaotic electrical activity in the heart that leads to ineffective heart contractions and a lack of blood flow to the body. This rhythm is life-threatening and requires immediate intervention. Defibrillation is necessary in this scenario because it aims to reset the heart's electrical activity, allowing the heart to regain a normal rhythm.

In contrast, normal sinus rhythm is a regular rhythm indicating that the heart is functioning properly. Asystole, which is the absence of any electrical activity in the heart, does not respond to defibrillation; instead, it typically requires other advanced cardiac life support measures. Atrial flutter is another type of abnormal rhythm, but it is often less critical than ventricular fibrillation and does not usually necessitate defibrillation unless it degenerates into a more severe arrhythmia. Therefore, the need for defibrillation is specifically indicated in cases of ventricular fibrillation.