Jun 1, 2015 
CPR and AEDs are both designed to give people suffering from cardiac arrest a chance at survival. Every year, approximately 326,200 victims suffer from cardiac arrest in the United States, and it is deadly—nine out of ten people who are struck by sudden cardiac arrest do not survive. Of those who do, many receive bystander CPR outside of a hospital—as most cardiac arrests happen in the home, at work, and other areas away from a medical care facility. General knowledge of cardiac arrest and CPR is crucial for public health.
But not everyone knows what sudden cardiac arrest is, how to treat it, or how to recognize it. Here are a few things everyone should know about cardiac arrest.
What is cardiac arrest?
The heart has an internal electrical system that keeps it beating in a regular, consistent rhythm. When that system fails, the heart can suffer an arrhythmia—an irregular fluttering of the ventricle chamber walls, abnormally fast or slow heartbeats, or even a cessation of beats altogether. When the heart isn’t working properly, it can’t push oxygenated blood from the lungs to the brain. The brain can start dying within minutes.
Sudden cardiac arrest occurs when the electrical system in the heart suddenly fails. It can occur in people who are not diagnosed with heart problems, and it can happen at any age.
What is the difference between cardiac arrest and a heart attack?
Many people think of these two things as interchangeable, but they are not actually the same thing. Heart attacks occur when a blockage in a vein or artery stops blood from flowing to the heart. As a result, muscle tissue in the heart can die due to the sudden blockage of blood supply. A heart attack can be extremely damaging, and can even lead to cardiac arrest—but it isn’t instantly deadly on its own.
Cardiac arrest, however, occurs when the electrical system of the heart fails to maintain proper beat rhythm and function. Many cardiac arrests are caused by a specific kind of arrhythmia, called a ventricular fibrillation, which is particularly deadly. During ventricular fibrillation, the lower chambers of the heart start fluttering and beating arrhythmically, and stop pumping blood altogether or pump it sporadically.
Unlike a heart attack, cardiac arrest is usually fatal within minutes. CPR can sometimes help, but an AED has the highest rate of effectiveness in treating sudden cardiac arrest. Victims who receive CPR and a shock from an AED within the first three minutes of a cardiac arrest can see their chances of survival improve by as much as 80%.
People recovering from heart attacks—or those suffering from an undiagnosed and untreated heart attack—have increased risk of cardiac arrest. However, most heart attacks do not result in sudden cardiac arrest.
What are the symptoms of cardiac arrest?
Cardiac arrest often appears to occur out of the blue. The victim suddenly collapses and is not responsive to outside stimuli. The victim will have no pulse, will not be breathing, and will not be conscious. It often looks like the person simply dropped dead for no reason.
Occasionally, signs occur just before an episode of cardiac arrest. These can include blackouts, dizziness, chest pain, weakness, heart palpitations, fatigue, fainting, or vomiting. However, it is just as common for victims to experience no signs of an impending attack.
As sudden as they can appear to be, however, a recent study suggests that many people experience signs of an incoming cardiac arrest days and even weeks before one occurs. The study found that people who survived sudden cardiac arrests reported experiencing chest pains as many as four weeks before the event. A smaller percentage experienced heart palpitations, dizziness, or shortness of breath.
What should I do if someone near me suffers a sudden cardiac arrest?
First, call 911 or have someone near you call 911. Get an AED if you can—these boost survival rates for sudden cardiac arrest by an unbelievable 80%. If there’s no AED in your building and the person isn’t breathing, start CPR.
In the past, the instructions for CPR include manipulating the person’s airway to make sure there was no obstruction, checking for a heartbeat, and using mouth-to-mouth rescue breaths. These days, it’s much simpler. Push hard and fast in the center of the person’s chest. Push harder than you think you have to, and do it to the rhythm of “Stayin’ Alive” by the Bee Gees. Keep it up until help arrives.
What are the long-term effects for survivors?
Cardiac arrest can be an extremely traumatic event for those who survive. Many of those who live through it don’t escape without a certain amount of brain damage; approximately 50% of survivors of cardiac arrest suffer from some amount of cognitive or physical impairment. However, studies are mixed as to the emotional and mental impact of a cardiac arrest event; some studies have found significant amounts of post-traumatic stress disorder, while others have found that victims do not suffer larger amounts of anxiety or emotional disability than people discharged from the hospital for other reasons.
However, those who survive sudden cardiac arrest are at risk of having arrhythmias occur again. Some take medications or have electric defibrillators surgically implanted to regulate their heartbeats.
Fast response to a cardiac arrest is crucial. Nerve cells start to die within minutes of being deprived of oxygen, and permanent brain damage or death can occur within just four to six minutes of a cardiac arrest. Because it’s so sudden and often not precluded by symptoms that indicate a serious problem, many people who suffer from cardiac arrest are nowhere near a hospital when it happens. Bystander CPR and AED use are crucial to survival, but few people receive it—even fewer in more economically disadvantaged communities.
That’s why learning CPR is so important—not just for medical professionals, but for anyone. The truth is that, since so many people are at home when they experience cardiac arrest, the person you save with your CPR skills is most likely to be a loved one.