cardiac arrest

Cardiac arrest is the sudden loss of heart function, where the heart unexpectedly stops contracting due to a problem in the conduction of electrical signals. Cardiac arrest leads to a loss of blood flow to vital organs, causing collapse within seconds.

Cardiac arrest occurs when the heart’s electrical control system breaks down, abruptly halting its ability to pump blood to the brain and other vital organs. The most common trigger is ventricular fibrillation, in which the lower chambers of the heart quiver chaotically instead of contracting in a coordinated beat. It may also result from ventricular tachycardia, a dangerously rapid rhythm that prevents the heart from filling and pumping effectively. In more severe cases, electrical activity may cease entirely—a condition known as asystole—or electrical signals may persist without producing a heartbeat, a state called pulseless electrical activity.

Although cardiac arrest is frequently described as sudden, about half of those affected report warning signs beforehand. In the hours or even days leading up to the event, individuals may experience chest discomfort, marked shortness of breath, a pounding or irregular heartbeat, nausea, or lightheadedness. Because these symptoms can resemble less serious conditions, they are sometimes overlooked.

Cardiac arrest requires immediate emergency care to restore circulation and prevent brain injury. Immediate cardiopulmonary resuscitation (CPR) to manually maintain blood flow to vital organs is essential. Rapid use of an automated external defibrillator (AED) is also critical, as it can deliver an electric shock to reset a dangerously abnormal heart rhythm. Emergency medical teams may also administer medications and provide advanced airway support. Survival depends heavily on how quickly these interventions begin, making early recognition and rapid response essential.