Which two life-threatening arrhythmias are known to cause cardiac arrest?

Ventricular fibrillation and pulseless ventricular tachycardia are both critical life-threatening arrhythmias that can lead to cardiac arrest. In ventricular fibrillation, the heart's electrical activity becomes chaotic, preventing it from effectively pumping blood, which halts blood circulation. This arrhythmia requires immediate defibrillation to restore a normal rhythm and is often associated with sudden cardiac arrest.

Similarly, pulseless ventricular tachycardia is characterized by a rapid heart rate that prevents effective heart contractions and blood flow, leading to a state where there is no detectable pulse. Like ventricular fibrillation, this condition is considered a critical emergency that typically requires advanced intervention, including defibrillation and CPR.

In contrast, while bradycardia (slow heart rate) and tachycardia (fast heart rate) can certainly affect the heart's function, they are not exclusively associated with cardiac arrest in the same way that the aforementioned arrhythmias are. Atrial fibrillation and flutter are types of atrial arrhythmias that can also lead to complications but do not directly cause cardiac arrest. Lastly, asystole represents a complete cessation of electrical activity in the heart, which, while life-threatening, is different from the dynamic environment of ventricular fibr