When someone suffers cardiac arrest, the heart suddenly stops beating due to an abnormal heart rhythm called ventricular fibrillation. Within seconds, the victim loses consciousness, collapses and has no pulse. Only immediate emergency treatment to restart the heart, such as CPR (cardiopulmonary resuscitation) and external defibrillation (electrical shock), can prevent death. Time is the key factor in survival for these victims. The American Heart Association recommends resuscitation within five minutes of collapse or sooner.

Because cardiac arrest stops the heart from pumping blood, the body and brain are deprived of oxygen. This deprivation causes cardiac arrest survivors to suffer brain damage that leads to poor neurological outcomes or death.

What is therapeutic hypothermia?

Therapeutic hypothermia is a process by which critical care doctors lower a patient’s body temperature, after the heart is restarted, to reduce the risk of brain injury following a period of insufficient blood flow. Under monitored sedation, patients are wrapped in specialized cooling pads to rapidly lower the body temperature to levels between 89.6 degrees Fahrenheit to 93.2 degrees Fahrenheit. (Normal body temperature is 98.6 degrees Fahrenheit.) Once cooled for 24 hours, patients are slowly re-warmed to a normal temperature. This therapy has been shown to significantly reduce brain damage and improve survival after cardiac arrest.

“Therapeutic hypothermia has become the gold standard in the treatment of post-cardiac arrest patients,” said Stephen W. Trzeciak, M.D., Emergency Medicine and Critical Care physician at Cooper.

Cooper University Hospital is leading South Jersey in utilizing therapeutic hypothermia. To date, nearly 100 hypothermia treatments have been performed, resulting in what Cooper cardiologist Perry J. Weinstock, M.D., Head of the Division of Cardiovascular Disease, describes as “a difference in (patient) outcomes that can not be overstated.”

How does therapeutic hypothermia work?

While cardiac arrest requires emergency treatment to restart the heart to prevent death, the restoration of circulation results in what is called reperfusion injury. Reperfusion injury refers to tissue damage caused by chemical reactions that occur when blood supply returns to tissue after a period of insufficient blood supply. The absence of oxygen and nutrients from blood creates a condition in which the reperfusion (the restoration of circulation) results in inflammation and cell damage.

Mild hypothermia is thought to suppress many of the chemical reactions associated with reperfusion injury. Therapeutic hypothermia has been shown to reduce mortality of successfully resuscitated cardiac arrest victims by 35 percent, and increase the chance of good neurologic outcome by 39 percent.

Where is therapeutic hypothermia available?

In its updated 2005 guidelines, the American Heart Association identified induced hypothermia as one of several beneficial therapies in the post-resuscitative care of cardiac arrest.

Yet, hypothermia treatment is unavailable at many hospitals.

“It is extremely important that emergency response personnel, area physicians and the community are aware that this proven treatment is not available at every hospital, and that Cooper is experienced in providing rapid and effective cooling for cardiac arrest victims,” said Cooper emergency medicine physician J. Hope Kilgannon, M.D., who also conducts research on post-cardiac arrest care.

“The longer the time that lapses between cardiac arrest and hypothermia treatment, the less successful the treatment may be,” Dr. Kilgannon said.

Remember, cardiac arrest can strike without warning. If you witness a cardiac arrest, call 9-1-1 or your local emergency response number immediately, and start CPR. The American Heart Association recommends that people learn both CPR and the simple procedure to operate an automated external defibrillator (AED). CPR and AED’s save lives.

Related Links

• Learn more about therapeutic hypothermia
• Critical Care Medicine
• Cooper Heart Institute
• Emergency Medicine

A Cooper cardiologist explains: “Heart disease is an umbrella term for a number of complex problems affecting the heart muscle, the blood vessels in the heart, and the veins and arteries leading to and from the heart. While all of the many types of heart disease differ, one can think of them in a simplified way as conditions that affect the rhythm and blood-flow of the heart,” said Perry J. Weinstock, M.D., Head of the Division of Cardiovascular Disease at Cooper University Hospital.

Heart Attack vs. Cardiac Arrest

Perhaps the most misunderstood terms related to heart problems is the difference between heart attack and cardiac arrest.

“Heart attack, which is caused by a circulatory problem in the heart, is quite different from cardiac arrest, which is caused by a rhythm problem in the heart,” Dr. Weinstock said. “A heart attack occurs when a coronary artery is blocked and the heart does not get the blood supply it needs, causing permanent damage to a portion of the heart muscle. All heart attacks are due to to circulatory problems; however, not all heart attacks cause the heart to stop beating.

“Approximately one-third of all heart attacks result in cardiac arrest or sudden death. In cardiac arrest, however, the heart does suddenly stop beating. The heart stops because a chaotic, irregular heart rhythm causes the heart to suddenly stop pumping blood. Cardiac arrest, also known as sudden cardiac death, results in a medical emergency, and may or may not be related to a heart attack. Sudden cardiac death is the number one killer among adults in the United States accounting for approximately 300,000 deaths per year,” Weinstock said.

Types of Heart Disease include:

Coronary Artery Disease (CAD) — the most common type and the leading cause of heart attacks. CAD is a narrowing and hardening of the arteries caused by the build up of plaque within the walls of the arteries that supply the myocardium—the muscular tissue of the heart. Angina pectoris (chest pain) is a frequent symptom of CAD. Myocardial infarction is the medical term for a heart attack.

Heart Failure — Heart failure, also known as congestive heart failure (CHF), is an umbrella term for different types of disorders marked by the inability of the heart muscle to pump enough blood throughout the body. This inability restricts the blood supply to other organs, resulting in damage to the organs or poor functioning of the organs. Heart failure has many causes, including untreated high blood pressure. Symptoms of heart failure include shortness of breath; swelling in the feet, ankles, and legs; and extreme tiredness. Heart failure does not mean that the heart stops beating.

Heart Arrhythmias — a group of conditions characterized by irregular heartbeat or abnormal heart rhythm due to a malfunctioning of the heart’s “electrical system”—or impulses that drive the beating/pumping action of the heart. Symptoms may include palpitations, dizziness, fainting, and shortness of breath and chest discomfort. Many different factors can cause arrhythmias, including CAD, electrolyte imbalances in the blood (such as sodium or potassium), changes in the heart muscle, and injury from a heart attack. Atrial fibrillation (A-Fib) is an irregular and often rapid heart rate that commonly causes poor blood flow to the body and symptoms of heart palpitations, shortness of breath and weakness. It is a common arrhythmia that requires close monitoring and treatment with medication or a corrective procedure. Ventricular fibrillation (V-Fib), on the other hand, is always a medical emergency. When V-Fib occurs, effective pumping of the blood stops. V-fib is considered a form of cardiac arrest, and an individual suffering from it will not survive unless CPR (cardiopulmonary resuscitation) and defibrillation treatment are provided immediately.

Cardiomyopathy — the deterioration of the function of the myocardium—the heart muscle. People with cardiomyopathy are often at risk of arrhythmia and/or sudden cardiac death. Many times, the cause of cardiomyopathy is unknown; however, the most common cause is CAD, heart attacks, or myocarditis (a viral infection that causes the heart muscle to become inflamed). Some people with cardiomyopathy never have symptoms, and others have no symptoms in the early stages of the disease; however, as it progresses, the symptoms are similar to heart failure.

Heart Disease Prevention

“Remember, many types of heart disease can be improved, or even prevented, by making certain lifestyle changes, such as not smoking, maintaining a healthy weight, staying physically active, eating healthful foods, managing stress, and controlling such conditions as high blood pressure, high cholesterol and diabetes,” said Dr. Weinstock.

“Also, don’t ignore the importance of regular medical check-ups. Early detection and treatment can set the stage for a lifetime of better heart health,” Dr. Weinstock said.