Sudden Cardiac Arrest


“The heart is a very resilient muscle,” says Woody Allen in his film Hannah and Her Sisters. And indeed it is. Charged with pumping blood throughout the entire circulatory system, the heart is also a muscle that reflects the treatment by its host more than any other muscle in the human body. Treat the heart well with frequent exercise, a good diet, and no smoking, and its potential to remain healthy improves dramatically. Treat the heart poorly with a cholesterol-laden, sedentary lifestyle and the chance of heart disease increases.


Sudden cardiac arrest, often caused by a combination of the above, is often confused with heart attack. “It is important to clarify the differences between these two conditions because people frequently lump them together,” says Dr. Michael Chen, assistant professor of medicine at the University of Washington in the division of cardiology.

Unlike a heart attack, which involves a blockage of the coronary artery and can lead to damage to the heart itself, sudden cardiac arrest is the result of a severely abnormal heart rhythm that stops the flow of blood to the rest of the body. A heart attack can actually cause sudden cardiac arrest when the arterial clot triggers an irregular heart beat. But although sudden cardiac arrest and heart attacks may occur together, it is possible to experience sudden cardiac arrest without a blockage in the artery.

“However,” according to Chen, “determining the patterns of sudden cardiac arrest can be a very complicated question, because it can also come out of the blue with no symptoms whatsoever.”

The most common symptoms of sudden cardiac arrest are sudden collapse, lack of pulse, no breathing, and loss of consciousness. Though sudden cardiac arrest can strike without warning, people experiencing heart palpitations; rapid or irregular heart beats; persistent chest pain; shortness of breath; blackouts, dizziness, or fainting; fatigue; and/or vomiting should see a doctor immediately.

The first step in treating sudden cardiac arrest is usually cardiopulmonary resuscitation (CPR), followed by a shock to the heart (defibrillation), an attempt to establish a normal heart rhythm. Advanced life support procedures (with EMT or in the emergency room) should follow.

Every moment becomes critical when a victim goes into sudden cardiac arrest. “The reason time is so important,” Chen continues, “is because when a person’s heart stops there is a very small window before the brain is lost. In fact, every minute that passes without defibrillating the heart reduces the chance of survival by 20 percent. And even if the victim does survive, neurological impairment often occurs.”

According to Chen, several research studies at the University of Washington are investigating the severity of cardiac arrest, including a potential breakthrough that involves cooling the patient to preserve the brain tissue and reduce stress while the patient’s body is under treatment. Chen also points out that defibrillation is considered so important, most airlines carry portable defibrillators. And because most cardiac arrests occur at home, keeping a home unit makes sense for high-risk individuals. However, if the high-risk individual lives alone, it may be time to consider a change of living arrangement, such as a move to assisted living. A person experiencing sudden cardiac arrest is simply unable to administer a defibrillator on herself.


“Like with heart attacks, healthy living is one of the best ways to lower the risk of sudden cardiac arrest. This includes eating a well-rounded diet of fruits, vegetables, and fish, exercising regularly, and reducing stress levels,” Chen observes. “Of course, not smoking is a given.”

Risk factors are not unlike those of heart attack and other coronary diseases:

  • Hypertension
  • Diabetes
  • Smoking
  • Advanced age
  • Cholesterol
  • Male gender
  • Sedentary lifestyle
  • Obesity
  • Family history of early coronary artery disease
  • People who have heart attacks when younger (Male less than 55, female less than 65)

The doctor will consider a number of tests to analyze the patient’s likelihood of a sudden cardiac arrest. These may include an electrocardiogram (ECG); blood tests such as a cardiac enzyme test, an electrolyte test, a drug test, and a hormone test. Imaging tests may also be performed, such as chest X-rays, nuclear scans, and echocardiograms. Finally, electrophysiological testing and mapping (to locate where in the heart an arrhythmia occurs), ejection fraction testing (to measure heart pumping capacity), and angiograms (to show narrowing or blockage of arteries) are also used as diagnostics.


Defibrillation is the most important response to a sudden cardiac arrest. In addition, doctors prescribe a variety of medications to assist recovery, alleviate pain, or prevent recurrence, including anti-arrhythmia drugs that slow the heart rate. Doctors also prescribe beta blockers, ACE inhibitors, calcium channel blockers, and amiodarone for high-risk patients.

The surgical implantation of animplantable cardioverter-defibrillator (ICD) may be the most effective method of preventing fatal arrhythmias in high-risk patients. This device monitors the patient’s heart rhythm and sends a shock to the heart to reset its rhythm when it detects an abnormal pacing or rhythms. Other surgical treatments may include:

  • Coronary angioplasty and/or bypass surgery (these procedures are described above in the heart attack section)
  • Radio frequency catheter ablation: An electrode designed to create an electrical block is implanted, stopping the arrhythmia.
  • Corrective heart surgery: This procedure is designed to repair congenital deformity, a faulty valve, or diseased heart tissue.
  • Heart transplantation

The usual preventive measures that apply to all cardiovascular diseases and conditions are equally important in preventing sudden cardiac arrest, including a well-balanced diet, a smoke free environment, and exercise. Frequent screening is advised after a certain age (determined by your doctor), especially for those with heart disease in the family.


Sudden cardiac arrest forces its victims to reevaluate their lifestyles and often their lives. This reflection often, but not always, leads to anxiety and depression, as the survivor believes his “time is almost up,” or laments the missed opportunities thus far in his life.

According to Chen, many survivors also suffer some degree of neurological impairment, from short term memory loss to persistent vegetative states (comas). The severity of the survivor’s impairment correlates with the swiftness of resuscitation, specifically how quickly she received electrical defibrillation (shock).

But even the placement of the implanted defibrillator, a common physical treatment after sudden cardiac arrest, can engender worry in the survivor. The devices occasionally discharge in error, shocking the user. Of course they are also a constant reminder to the patient of his new physical vulnerability.

“[The patient’s family] should also be closely monitored for depression and guilt,” Chen says. “They often feel they did not do or know enough to help prevent the traumatic events of a sudden cardiac arrest. Their loved one’s impaired state serves as a constant reminder of this inadequacy.”

Heart attacks and sudden cardiac arrest starkly remind us of our physical vulnerabilities, often a consequence of unhealthy lifestyle choices. They are the heart’s way of telling us in no uncertain terms that we need to change our routines, if not our entire way of life, if we want to continue living.

Over 25 percent of the deaths in 2003 were the result of heart disease, by far the leading cause of death in the United States. Someone dies from heart disease every forty-six seconds. The onset of heart disease forces people to confront death, an experience that makes most of us feel frightened and helpless. Yet we can make daily decisions to fight heart disease when we choose to exercise, to avoid smoking, and to eat a healthier diet high in fruits and vegetables and low in saturated fats, and encourage those we love to do the same. Modern medical advances, together with our determination to change, can now give us and our loved ones a second chance to fully live our lives for years, even decades, to come.


Update: January 2018