Understanding Sudden Cardiac Arrest

Sudden cardiac arrest (SCA) accounts for 300,000 to 350,000 deaths annually in the United States1. It is the leading cause of death in our country, claiming more lives each year than breast cancer, lung cancer, or AIDS2. Coronary heart disease accounts for approximately 80 percent of sudden cardiac deaths in Western countries3. Other causes include cardiomyopathies, inherited abnormalities, and valvular heart disease3. Arrhythmia is the overwhelming cause of SCA4.

October is Sudden Cardiac Arrest Awareness Month. The goal of this initiative is to increase awareness of SCA and educate the public about what it is and how we can help save lives. The majority of patients who suffer SCA exhibit no warning signs. Receiving immediate treatment is critical to survival. The chance for a successful resuscitation after SCA decreases by 7 to 10 percent for every minute delay in treatment5. It is estimated that 95 percent of SCA victims die because they do not receive life-saving defibrillation within four to six minutes. It is critical for healthcare providers and the general public to understand how to respond to SCA.

Sudden cardiac arrest occurs without warning. The victim may suddenly collapse or fall to the ground. He or she will be unconscious and may exhibit an unusual breathing pattern, or show no signs of breathing at all. The keys to an SCA emergency include: 

  • Call 911. 
  • Initiate immediate CPR. Start chest compressions hard and fast at approximately 100 beats per minute with limited interruption. 
  • Use an automatic external defibrillator (AED) as soon as possible.

It is important to understand who is at risk for SCA so measures can be taken to prevent it. A person who has had a previous heart attack is four to six times more likely to suffer SCA than the general population6. Patients with a cardiomyopathy (weak heart muscle) are also at increased risk. If a relative died suddenly at a young age of a suspected cardiac event, there could be an inherited condition that puts the person at a higher risk for SCA.

Controlling cardiac risk factors remains ever important in preventing coronary heart disease and the risk of SCA. There are many therapies at our disposal to treat patients known to be at high risk of SCA. Along with lifestyle modification, appropriate medical therapy can help decrease the risk of SCA. An automatic implantable cardioverter defibrillator can be implanted to monitor a patient's heart rhythm, recognize a potential life-threatening arrhythmia, and deliver a pacing therapy or a shock to restore the heart to a normal rhythm. These implantable devices save lives when used in patients with a high risk for SCA.

Having more AEDs in public places such as airports, gyms, schools, and malls increases the likelihood that SCA victims will receive a potentially lifesaving shock within that critical window.

Sudden cardiac arrest can occur in people of all ages and health conditions. It can occur without warning. It is important for physicians to educate their patients and the general public about the risk factors for SCA. Having the right information at the right time can save a life. 

  1. J Am Coll Cardiol.2006; 48(5): e247-e346.

  2. Zheng Z. Circulation. 2001; 104: 2158-2163.

  3. Hekki et al. N Engl J Med, vol. 345, No. 20, 2001.

  4. Albert CM. Circulation. 2003; 107: 2096-2101.

  5. Cummings RO. Annals Emerg Med. 1989; 18: 1269-1275.

  6. American Heart Association. Heart Disease and Stroke Statistics-2003 Update.

About the Author
Brett C. Burgess, M.D., FACC
, is a cardiologist who practices at Cardiovascular Consultants, P.C. He is also the medical director of noninvasive cardiology at Memorial University Medical Center.