An Automated External Defibrillator (AED) is a user-friendly medical device designed to assist individuals experiencing sudden cardiac arrest. While often depicted as “restarting” a heart that has ceased all activity, this perception is inaccurate. An AED’s purpose is to correct specific electrical malfunctions within the heart, not to revive a flatlined heart.
Understanding AED Function
An AED delivers a controlled electrical shock to the heart, not to initiate a beat from a completely stopped heart. Instead, the shock aims to reset a heart experiencing chaotic and ineffective electrical activity. Like a computer reboot, the AED provides an electrical “stun.” During sudden cardiac arrest, the heart’s electrical system can malfunction, leading to disorganized signals that prevent it from pumping blood effectively, even if electrical activity is present. The electrical discharge momentarily stuns the heart, allowing its natural pacemaker to regain a normal, organized rhythm.
Treatable Heart Rhythms
AEDs are designed to treat two life-threatening heart rhythms: ventricular fibrillation (VF) and pulseless ventricular tachycardia (pVT). In ventricular fibrillation, the heart’s lower chambers quiver chaotically, unable to pump blood. Pulseless ventricular tachycardia occurs when the heart beats extremely fast, too inefficient to circulate blood. Conversely, an AED cannot deliver a shock to a heart that has flatlined (asystole), because there is no electrical activity for the device to reset. If asystole is detected, the AED will advise “no shock,” indicating defibrillation is not a viable treatment.
Using an AED Effectively
Using an AED involves straightforward steps, guided by voice prompts, lights, and text messages. First, call emergency services immediately for any suspected cardiac arrest. Turn on the AED, expose the person’s chest, and place pads on the upper right and lower left sides. The AED then analyzes the heart’s rhythm; ensure no one touches the person during this analysis for an accurate reading. If a shockable rhythm is detected, the AED instructs rescuers to stand clear before automatically delivering the shock or prompting the user to press a button.
The Role of CPR and Emergency Services
An AED is an important component of the “Chain of Survival” for sudden cardiac arrest, but it is not a standalone solution. Immediate, high-quality Cardiopulmonary Resuscitation (CPR) is crucial both before and after AED use, and while waiting for professional medical assistance. CPR helps maintain blood flow to the brain and other vital organs until defibrillation can occur or emergency medical personnel arrive. Calling 911 (or equivalent) is the first step in managing a cardiac emergency. These combined efforts significantly increase the chances of survival for someone experiencing sudden cardiac arrest.