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Some background on SCA - How the Heart Works:
The heart is one of the strongest muscles in the body. It keeps our blood flowing, sustaining life. Think of the heart as an efficient pump. For proper circulation to occur, the heart requires rhythmic coordination between its parts.
If you've ever listened to a heartbeat, you'd have noticed not one thump, but two rapid ones - that's due to the split-second coordination between the upper chambers of the heart (the atria; a single one is called an 'atrium') and the lower chambers (the ventricles).
In a healthy heartbeat, electrical impulses sent out by the heart's natural pacemaker cause the atria to contract first. They push blood into the ventricles, which then pump blood into either the lungs, to be oxygenated, or out into the body. The slight delay between the chambers allows the ventricles to completely fill before they contract, ensuring a strong heartbeat.
Sudden Cardiac Arrest is usually caused by an abnormal heart rhythm called Ventricular Fibrillation (VF). When this happens, the heart's natural coordination between its electrical and mechanical systems is thrown off. The electrical impulses, usually steady and rhythmic, become chaotic and disordered. The result is uncoordinated contractions, which cause the heart to quiver uselessly. In this state, the heart is unable to pump blood through the body. Blood pressure drops, pulse and breathing stop, and the victim collapses suddenly, unresponsive.
SCA is often mistaken for a heart attack. While a heart attack can lead to SCA, the terms are not synonymous. The conditions have key differences, particularly in their symptoms.
| Heart Attack Symptoms |
SCA Symptoms |
| Pressure, squeezing, or other discomfort |
Often no warning - strikes immediately |
| Pain in the arms, back, neck, jaw, or stomach |
Sudden loss of breathing |
| Shortness of breath |
No pulse |
| Cold sweats, nausea, lightheadedness |
No movement or coughing - victim appears lifeless |
When a heart attack happens, there may be time for the victim to call for help or be taken to the hospital. However, if SCA occurs due to a heart attack, there is usually no warning, and treatment must be given within minutes for the person to survive. In fact, for every minute the victim waits, their chance of survival drops by 7-10%. After as little as 10 minutes, the chance for survival is gone. To put that in perspective, the average EMS response time in the U.S. from collapse to defibrillation is estimated at 10 to 12 minutes - beyond the window of opportunity for survival.
SCA is not a rare occurrence, and it's not limited to those with pre-existing heart conditions or poor health. It's one of the leading causes of death in American adults, and can strike anyone, anywhere, anytime, and at any age. Roughly 700 people die each day from this condition - about one death every two minutes. The American Heart Association estimates that up to 50,000 lives a year could be saved if an AED had been available at the time of the emergency. That's a lot of people given another chance at life - all thanks to an easy-to-use, low maintenance machine.
Though they may sound like a brand-new form of medical technology, AEDs have actually been around in some form for more than 25 years. Read on to learn more about the growing history and improvement of defibrillation technology and AEDs.
Learn even more about AEDs and Sudden Cardiac Arrest. Continue on or click any of the links below to go directly to that topic. |
