Which rhythms are considered shockable in cases of cardiac arrest?

In cases of cardiac arrest, the rhythms that are deemed shockable include ventricular fibrillation and ventricular tachycardia. Ventricular fibrillation is a chaotic, irregular heart rhythm that leads to ineffective heart beats and significantly impairs blood circulation, making immediate defibrillation essential. Ventricular tachycardia, particularly when it is pulseless (without a detectable pulse), can also lead to a similar situation where the heart is unable to pump blood effectively, necessitating shock to restore a normal rhythm.

Defibrillation works by delivering a controlled electric shock to the heart, which can cause the heart muscle to depolarize simultaneously in hopes of re-establishing an effective rhythm. In contrast, asystole and pulseless electrical activity (PEA) are non-shockable rhythms. Asystole represents a complete absence of electrical activity in the heart, while PEA presents with electrical activity on the monitor without effective cardiac output, neither of which can be treated with defibrillation. Bradycardia, while it can be serious, does not typically warrant immediate shock unless it leads to instability or other complications.

Thus, recognizing ventricular fibrillation and ventricular tachycardia as shockable rhythms is crucial in emergency medicine, as