Yes, ventricular fibrillation (V-Fib) can be defibrillated, and it is the most effective treatment for this life-threatening condition. V-Fib is an electrical emergency in the heart that leads to sudden cardiac arrest, and delivering an electrical shock is the only way to potentially restore a normal rhythm. The use of a device called a defibrillator, which includes the widely available Automated External Defibrillator (AED), is specifically designed to treat the chaotic electrical activity characteristic of V-Fib. When a person collapses due to V-Fib, rapid action involving both cardiopulmonary resuscitation (CPR) and prompt defibrillation provides the greatest chance for survival.
What Happens During Ventricular Fibrillation
Ventricular fibrillation occurs when the heart’s electrical system completely loses its organized, rhythmic control. Normally, the lower chambers of the heart, the ventricles, contract in a synchronized manner to pump blood out to the rest of the body. This action is driven by electrical signals originating from the heart’s natural pacemaker.
During V-Fib, the electrical impulses become disorganized and chaotic, firing rapidly and randomly from multiple locations within the ventricles. Instead of contracting forcefully to pump blood, the heart muscle simply quivers or “fibrillates” in an ineffective manner. This unsynchronized electrical activity means that no effective blood is being circulated throughout the body.
Since the ventricles fail to pump, blood flow to the brain and other vital organs ceases almost immediately. This lack of circulation leads to a loss of consciousness and the absence of a pulse, which constitutes sudden cardiac arrest. Without immediate intervention, this state is rapidly fatal, as the body’s tissues are starved of oxygen.
How Defibrillation Resets the Heart
Defibrillation works by delivering a high-energy electrical current across the chest to the heart muscle. Its purpose is to momentarily stop all electrical activity in the heart. The shock essentially depolarizes a significant portion of the heart muscle cells simultaneously.
This brief, induced electrical silence interrupts the chaotic, disorganized signals that characterize V-Fib. By clearing the abnormal electrical activity, the shock gives the heart’s natural pacemaker, the sinoatrial (SA) node, an opportunity to regain control. The SA node is the heart’s primary generator of electrical impulses, allowing it to re-establish a normal, synchronized rhythm.
The speed of this intervention directly impacts the chance of survival because the success rate of defibrillation declines significantly with every minute of delay. For each minute without intervention, the survival rate decreases by approximately 10%. Modern defibrillators often use a biphasic waveform, which delivers the charge in two directions at a lower energy level, proving more effective at terminating these rhythms than older monophasic devices.
Practical Steps for Using an AED
Using an Automated External Defibrillator (AED) is a direct part of the immediate response to a suspected cardiac arrest. The first step is recognizing the emergency: if a person collapses, is unresponsive, and is not breathing normally, emergency services must be called immediately. High-quality chest compressions (CPR) should be started and continued until the AED is ready to use.
Once the AED is retrieved and turned on, the device provides clear voice and visual prompts to guide the rescuer. The rescuer must quickly expose the person’s bare chest and apply the electrode pads in the locations shown on the diagrams, typically one on the upper right chest and one on the lower left side. The pads are then plugged into the AED unit, allowing the device to analyze the heart’s electrical rhythm.
During the analysis phase, no one should touch the victim to prevent interference with the reading. The AED automatically determines if the rhythm is shockable, such as V-Fib or pulseless ventricular tachycardia. If a shock is advised, the device will announce it, charge the capacitor, and instruct the rescuer to press the shock button after ensuring everyone is clear of the patient. Following the shock, or if no shock is advised, the rescuer must immediately resume CPR, continuing to follow the AED’s prompts until professional medical help arrives.