The average heart beats about 100,000 times daily, each beat coordinated by the heart's intricate electrical system. Dangerous electrical disturbances can stop the beating heart, leading to what’s known as cardiac arrest. Severe heart failure, a heart attack, genetic disorders, certain medications and street drugs can trigger abnormal electrical rhythms that can cause the heart to stop. According to the American Heart Association, about 400,000 sudden cardiac arrests occur yearly, most happening outside a medical facility. Even if you’re not a medical professional, quickly starting cardiopulmonary resuscitation and using an automated external defibrillator can help restart the heart and save a life.
The AHA estimates that bystander CPR provided right away after sudden cardiac arrest can more than double a person’s odds of survival. CPR is critical for maintaining blood flow to vital organs, including the brain and kidneys, until an ambulance arrives. Because CPR has traditionally involved a combination of rescue breathing and chest compressions, bystanders are often reluctant to perform CPR. Data from recent studies, including a study published in the June 2010 issue of "The New England Journal of Medicine," has shown that compression-only CPR is just as effective as standard CPR in adults. This prompted the AHA to begin recommending compression-only CPR for teens and adults. The AHA currently advises bystanders to call 911 immediately and begin chest compressions as soon as possible after finding a teen or adult who is unresponsive without a pulse. Infants and children who have not yet undergone puberty still require rescue breathing in addition to chest compressions.
Automated External Defibrillators
Like CPR, using an AED can improve chances of survival after cardiac arrest. AED devices can be found at most shopping malls, airports, schools and stadiums. While calling 911 and beginning CPR immediately are still crucial, use of an AED can help restore a normal heart rhythm before medical personnel arrive. Certain abnormal heart rhythms respond to the delivery of an electrical shock, or defibrillation, which allows the heart to be restarted. Once an AED is turned on, a series of audio prompts deliver instructions on how to use it. According to the AHA, chances of survival following cardiac arrest are greatest when defibrillation occurs within 3 to 5 minutes of the victim’s initial collapse and loss of a pulse.
Once emergency medical workers arrive at the scene of a sudden cardiac arrest, powerful medications may also be used to help restart the heart. Epinephrine (adrenaline) can be injected into the bloodstream to stimulate the heart and encourage it to resume a normal electrical rhythm. The medication vasopressin is also sometimes used to help improve blood pressure during cardiac arrest. Depending on the nature of the arrest, other medications may be given to reverse the suspected underlying cause. Once the heart has been successfully restarted, other medications are used to stabilize blood pressure until the person can be transported to a hospital.
Prognosis after sudden cardiac arrest depends on a number of factors, including the person's age and health before the arrest. People who have serious medical conditions or have already experienced a stroke or brain injury before cardiac arrest are less likely to have good outcomes. The amount of time that passes before starting CPR and using an AED is also an important factor. Every second counts during a cardiac arrest -- the sooner you call 911 and begin CPR, the better.