What is sudden cardiac arrest?

Sudden cardiac arrest (SCA) is a sudden loss of pulse and blood pressure, usually due to cardiac arrhythmia, primarily ventricular fibrillation. About half of all deaths from coronary heart conditions occur suddenly, and over 400,000 adults in the U.S. die from SCA each year.

How is sudden cardiac arrest different from a heart attack?

Sudden cardiac arrest is caused by an electrical malfunction of the heart rhythm. A heart attack, or myocardial infarction, is a result of acute ischemia, or lack of oxygen in the heart. A heart attack occurs when the blood supply for part of the heart muscle - the myocardium - is severely reduced or stopped. This occurs when one or more arteries that supplies blood to the heart muscle (coronary artery) is blocked by an obstruction, either of plaque from atherosclerosis, a blood clot, or other causes.

What causes sudden cardiac arrest?

Sudden cardiac arrest is caused by ventricular arrhythmia, an abnormality in the beating pattern of the heart resulting in alterations in the rate and frequency of the electrical impulses in the ventricles. The victim immediately stops breathing, has little or no detectable pulse and, with no intervention, will die within minutes. Most people who suffer from a ventricular arrhythmia have an underlying electrical disorder of the heart that can be non-invasively detected by the Microvolt T-Wave Alternans Test.

Who is at risk for sudden cardiac arrest?

People with previous episodes of cardiac arrest or life threatening ventricular arrhythmias are at highest risk as are people with documented heart disease and symptoms of possible arrhythmias such as fainting. Also of elevated risk are patients with congestive heart failure, prior heart attack, family history of sudden death and coronary artery disease. Your doctor can tell you if you are a candidate for a Microvolt T-Wave Alternans test.

What tests can I take to find out if I am at risk for sudden cardiac arrest?

Prior to the Cambridge Heart Microvolt T-Wave Alternans Test, there has not been an accurate, non-invasive way to predict a patient's risk for life-threatening arrhythmia. Non-invasive tests such as the conventional exercise stress test and echocardiograph do not specifically identify risk of ventricular arrhythmia. The most definitive and reliable method for detecting risk for sudden cardiac arrest is the electrophysiology (EP) test, an invasive test. However, difficulties in non-invasive risk stratification result in only a small percentage of vulnerable patients undergoing EP testing.

Are there definitive treatments for sudden cardiac arrest?

The underlying causes of predisposition to sudden cardiac arrest are varied and no fundamental treatment currently exists. However, the primary symptom of SCA - the life-threatening arrhythmia - can be stopped with a defibrillation device that restores the heart's natural rhythm by applying an electrical shock. Defibrillation can be achieved through an automatic external defibrillator (AED), which are used by paramedics and first responders and are becoming increasingly deployed on airplanes and other venues where emergency medical response may be less accessible, or through an implanted cardioverter defibrillator (ICD). Increasingly, physicians are implanting small cardioverter defibrillators in their high-risk patients as a prophylactic means for averting sudden cardiac death. Anti-arrhythmic drugs such as Amiodarone are also used with high-risk patients. Other drugs such as Beta blockers have also been shown to reduce cardiac arrest risk.

Dr. Singer is Executive Medical Director of Cardiovascular Services at Methodist. He is also a board-certified cardiologist with Methodist Medical Group Cardiology, with a special interest in electrophysiology He sees patients at his Peoria office, and at Methodist Medical Group locations in Canton, Chillicothe, Morton, Pekin and Princeville.