What Is Cardiac Arrest?

What is cardiac arrest? People die from cardiac arrest every day all around the world, but most people don't actually know what happens during cardiac arrest. Cardiac arrest kills approximately 95 percent of its victims even when they receive help quickly. Most people believe that cardiac arrest strikes without warning, leaving victims helpless to prevent it. Sometimes cardiac arrest does strike out of the blue, without warning signs, but the majority of the time there are signs and symptoms that go ignored or misunderstood, causing people to miss the opportunity to save their own life.

A heart attack and cardiac arrest are two different things. A heart attack takes place when portions of the heart muscle are deprived of blood flow and oxygen, which causes damage to the heart muscle. Sudden cardiac arrest is actually a complete loss of heart function, which leads to loss of consciousness, breathing and pulse. Frequently, sudden cardiac arrest is caused by disturbances in the heart's delicate electrical system. That is the reason why victims of sudden cardiac arrest are frequently shocked with a defibrillator in order to get their hearts functioning once again.

There are two cardiac rhythm disturbances that can lead to cardiac arrest which respond favorably to electrical shocks from a defibrillator. They are ventricular tachycardia and ventricular fibrillation. Ventricular tachycardia is a rapid heart beat that originates in the heart's ventricles. Ventricular tachycardia originates in the ventricles and consists of a heart rate of more than 100 beats per minute with at least three irregular heart beats in a row. Ventricular tachycardia can have many causes, including an enlarged heart, heart attack, myocarditis, scar tissue or low potassium levels in the blood. Ventricular fibrillation is generally caused by an electrical disturbance, and it originates in the ventricles as well. Ventricular fibrillation causes the heart's ventricles to flutter, creating an inability for the heart to pump blood effectively. Both ventricular tachycardia and ventricular fibrillation respond to electrical shocks from a defibrillator and can often be converted back to a normal rhythm. Both of these electrical disturbances within the heart can lead to sudden cardiac arrest.

Have you ever wondered why you see automatic external defibrillators, or AEDs, on the walls anywhere that large numbers of people congregate? It's because early intervention with a defibrillator can save the life of victims of cardiac arrest by restoring a normal heart rhythm. Victims of cardiac arrest often have had signs and symptoms that something is awry, or they have a known heart condition. Individuals suffering from lightheadedness, sudden fatigue, shortness of breath or fainting should be seen by a medical professional immediately. Sometimes you will only get one warning that something is wrong; if you ignore that warning, you have missed an opportunity to potentially save your life. Middle-aged men in particular are known for "cardiac denial," which is where signs and symptoms of a cardiac problem are ignored or dismissed, leading to a heart attack or sudden cardiac arrest. Medical advances have made many cardiac problems highly treatable using medication or surgical intervention. Patients suffering rhythm disturbances can have a cardiac pacemaker implanted which will automatically send an electrical impulse to the heart muscle in the event there is an arrhythmia, thereby avoiding cardiac arrest.

Cardiac arrest is always a loss of heart function, whereas a heart attack is a disruption of blood flow to portions of the heart muscle. Heart attacks are generally caused by a physical blockage of a coronary artery. Cardiac arrest is often brought on by a disruption of the heart's electrical system, causing it to cease functioning altogether.

Resources:

American Heart Association

University of Maryland Medical Center

Mayo Clinic