Which two rhythms are considered shockable during cardiac arrest?

During a cardiac arrest, the two rhythms that are classified as shockable are Ventricular Fibrillation and Ventricular Tachycardia. Ventricular Fibrillation is a chaotic electrical activity in the heart that prevents it from effectively pumping blood, leading to a life-threatening situation. Defibrillation is necessary because delivering a shock can restore a normal rhythm by discharging the chaotic electrical activity and allowing the heart to re-establish effective electrical conduction.

Ventricular Tachycardia, on the other hand, is characterized by a rapid heart rhythm originating from the ventricles, which can also prevent the heart from pumping blood efficiently. If the patient is conscious and stable, the rhythm might not require immediate defibrillation; however, if the patient is unstable or pulsless, defibrillation is indicated.

Both of these rhythms contrast with non-shockable rhythms such as Asystole, which is a complete absence of electrical activity in the heart, and is not effectively treated with defibrillation. Instead, Asystole requires other resuscitation efforts like high-quality CPR and administration of medications. This distinction is essential in ACLS as it guides the appropriate treatment during a resuscitation effort.