Which two arrhythmias are considered lethal?

The two arrhythmias that are considered lethal are A-systole and V-fib.

A-systole, often referred to as "flatline," indicates the absence of electrical activity in the heart, which means that the heart is not contracting and there is no blood circulation. This condition is critical and requires immediate resuscitation efforts, as survival is impossible without timely intervention.

V-fib, or ventricular fibrillation, involves chaotic electrical activity in the ventricles, preventing them from effectively contracting. This leads to inadequate blood flow to the body's organs and can result in sudden cardiac arrest if not treated promptly with defibrillation.

Together, these arrhythmias pose an immediate threat to life, making early identification and management crucial in emergency situations.