Every year, some 300,000 Americans die from sudden cardiac arrest, which should be differentiated from heart attack. In fact, a heart attack may actually cause sudden cardiac death either during the first few hours of the heart attack or up to many years after the attack.
We can consider sudden cardiac death as an electrical malfunction while heart attack as one that is caused by blocked arteries (plumbing malfunction). Sudden cardiac arrest is a potentially deadly event, in which heart stops contracting and fails to pump blood properly.
When such event occurs in public places like airport or shopping mall, any bystanders could save the life of the victim using automatic external defibrillator (AED). A study conducted by researchers at Johns Hopkins University in Baltimore reported that bystanders using battery-operated defibrillators might be saving more than 500 lives every year in the United States and Canada. The findings were presented at an American Heart Association meeting in Orlando, Florida, on November 5, 2008.
The automatic defibrillators are of laptop size and are portable. They come with full set of instructions so that even the untrained bystanders could be guided through the rescue process. The defibrillator analyzes the person's heart rhythm and delivers a shock when necessary through the electrodes placed on the victim’s chest.
In the study, the researchers analyzed patient records from more than 10,600 incidents of cardiac arrest called into 911 emergency telephone lines in the 11 cities in the United States and Canada.
It is found that bystanders administered CPR (cardiopulmonary resuscitation) in nearly 30 percent of the cases, while in 2.4 percent of the cases, bystanders offered CPR together with automated defibrillator. There was only 259 patients had been offered an AED by a bystander. Their survival is very good. If patients needed a shock and device shocked them, their survival rate is 36 percent, as compared to the overall rate of 7 percent.
Since the AEDs are available in public places, where people could get them fast in case of emergency, the survival rates with a defibrillator are about 2.5 times better than with the help of CPR alone.
The study advocates wider use of AEDs as the cost is considerably affordable. According to the researchers, for example, putting in AEDs in a building with 1,000 people will cost US$3,000, which is less than the price of a cup of latte.