Sudden cardiac arrest is the sudden, unexpected loss of heart function, breathing and consciousness. Sudden cardiac arrest usually results from an electrical disturbance in your heart that disrupts its pumping action, stopping blood flow to the rest of your body.
Sudden cardiac arrest is different from a heart attack, which occurs when blood flow to a portion of the heart is blocked. However, a heart attack can sometimes trigger an electrical disturbance that leads to sudden cardiac arrest.
Sudden cardiac arrest is a medical emergency. If not treated immediately, it causes sudden cardiac death. With fast, appropriate medical care, survival is possible. Administering cardiopulmonary resuscitation (CPR), treating with a defibrillator â or even just compressions to the chest â can improve the chances of survival until emergency personnel arrive.
Source: http://www.mayoclinic.com
Sudden cardiac arrest symptoms are immediate and drastic and include:
Sometimes other signs and symptoms precede sudden cardiac arrest. These may include fatigue, fainting, blackouts, dizziness, chest pain, shortness of breath, weakness, palpitations or vomiting. But sudden cardiac arrest often occurs with no warning.
If you have frequent episodes of chest pain or discomfort, heart palpitations, irregular or rapid heartbeats, unexplained wheezing or shortness of breath, fainting or near fainting, or you're feeling lightheaded or dizzy, see your doctor promptly. If these symptoms are ongoing, you should call 911 or emergency medical help.
When the heart stops, the lack of oxygenated blood can cause brain damage in only a few minutes. Death or permanent brain damage can occur within four to six minutes. Time is critical when you're helping an unconscious person who isn't breathing. Take immediate action.
Perform CPR. Quickly check the unconscious person's breathing. If he or she isn't breathing normally, begin CPR. Push hard and fast on the person's chest â at the rate of 100 to 120 compressions a minute. If you've been trained in CPR, check the person's airway and deliver rescue breaths after every 30 compressions.
If you haven't been trained, just continue chest compressions. Allow the chest to rise completely between compressions. Keep doing this until a portable defibrillator is available or emergency personnel arrive.
Use a portable defibrillator, if one is available. If you're not trained to use a portable defibrillator, a 911 or emergency medical help operator may be able to guide you in its use. Deliver one shock if advised by the device and then immediately begin CPR starting with chest compressions, or give chest compressions only, for about two minutes.
Using the defibrillator, check the person's heart rhythm. If necessary, the defibrillator will administer a shock. Repeat this cycle until the person recovers consciousness or emergency personnel take over.
Portable automated external defibrillators (AEDs) are available in an increasing number of places, including airports, casinos and shopping malls. You can also purchase them for your home. AEDs come with built-in instructions for their use. They're programmed to allow a shock only when appropriate.
Source: http://www.mayoclinic.com
The immediate cause of sudden cardiac arrest is usually an abnormality in your heart rhythm (arrhythmia), the result of a problem with your heart's electrical system.
Unlike other muscles in your body, which rely on nerve connections to receive the electrical stimulation they need to function, your heart has its own electrical stimulator â a specialized group of cells called the sinus node located in the upper right chamber (right atrium) of your heart. The sinus node generates electrical impulses that flow in an orderly manner through your heart to synchronize the heart rate and coordinate the pumping of blood from your heart to the rest of your body.
If something goes wrong with the sinus node or the flow of electric impulses through your heart, an arrhythmia can result, causing your heart to beat too fast, too slow or in an irregular fashion. Often these interruptions in rhythm are momentary and harmless. But some types of arrhythmia can be serious and lead to a sudden stop in heart function (sudden cardiac arrest).
The most common cause of cardiac arrest is an arrhythmia called ventricular fibrillation â when rapid, erratic electrical impulses cause your ventricles to quiver uselessly instead of pumping blood.
Most of the time, cardiac-arrest-inducing arrhythmias don't occur on their own. In a person with a normal, healthy heart, a lasting irregular heart rhythm isn't likely to develop without an outside trigger, such as an electrical shock, the use of illegal drugs or trauma to the chest at just the wrong time of the heart's cycle (commotio cordis).
A life-threatening arrhythmia usually develops in a person with a pre-existing heart condition, such as:
Source: http://www.mayoclinic.com
If you experience an episode of sudden cardiac arrest without warning and survive, your doctor will want to investigate what caused the cardiac arrest. Identifying the underlying problem may help prevent future episodes of cardiac arrest.
Tests your doctor may recommend include:
A test commonly given after cardiac arrest is an electrocardiogram (ECG). During an ECG, sensors (electrodes) that can detect the electrical activity of your heart are attached to your chest and sometimes to your limbs. An ECG can reveal disturbances in heart rhythm or detect abnormal electrical patterns, such as a prolonged QT interval, that increase your risk of sudden death.
A sample of your blood may be tested to check the levels of potassium, magnesium, hormones and other chemicals that may affect your heart's ability to function properly. Other blood tests can detect recent heart injury and heart attacks.
These may include:
Other tests that are often done include:
Electrical system (electrophysiological) testing and mapping. With this type of test, your doctor may try to cause an arrhythmia while closely monitoring your heart. The test can help locate where in the heart the arrhythmia starts.
During the test, thin, flexible tubes (catheters) tipped with electrodes are threaded through your blood vessels to a variety of spots within your heart. Once in place, the electrodes can precisely map the spread of electrical impulses through your heart.
Coronary catheterization (angiogram). During this procedure, a liquid dye is injected into the arteries of your heart through a long, thin tube (catheter) that's advanced through an artery, usually in your leg, to arteries in your heart. As the dye fills your arteries, the arteries become visible on X-ray and videotape, revealing areas of blockage.
While the catheter is in position, your doctor may treat a blockage by performing an angioplasty and inserting a stent to hold the artery open.
Ejection fraction testing. One of the most important predictors of your risk of sudden cardiac arrest is how well your heart is able to pump blood. Your doctor can determine your heart's pumping capacity by measuring what's called the ejection fraction. This refers to the percentage of blood that's pumped out of a filled ventricle with each heartbeat.
A normal ejection fraction is 55 to 70 percent. An ejection fraction of less than 40 percent increases your risk of sudden cardiac arrest.
Your doctor can measure ejection fraction in several ways, such as with an echocardiogram, magnetic resonance imaging (MRI), a nuclear medicine scan (multiple gated acquisition, or MUGA), a computerized tomography (CT) scan or a cardiac catheterization.
Source: http://www.mayoclinic.com
When sudden cardiac arrest occurs, your brain is the first part of your body to suffer because, unlike other organs, it doesn't have a reserve of oxygen-rich blood. It's completely dependent on an uninterrupted supply of blood. Reduced blood flow to your brain causes unconsciousness.
If your heart rhythm doesn't rapidly return to its normal rhythm, brain damage occurs and death results. If sudden cardiac arrest lasts more than 8 minutes, survival is rare. Survivors of cardiac arrest may show signs of brain damage.
Source: http://www.mayoclinic.com
There's no sure way to know your risk of sudden cardiac arrest, so reducing your risk is the best strategy. Steps to take include regular checkups, screening for heart disease and living a heart-healthy lifestyle with the following approaches:
If you know you have heart disease or conditions that make you more vulnerable to an unhealthy heart, your doctor may recommend that you take appropriate steps to improve your health, such as taking medications for high cholesterol or carefully managing diabetes.
In some people with a known high risk of sudden cardiac arrest â such as those with a heart condition â doctors may recommend anti-arrhythmic drugs or an implantable cardioverter-defibrillator (ICD) as primary prevention.
If you have a high risk of sudden cardiac arrest, you may also wish to consider purchasing an automated external defibrillator (AED) for home use. Before purchasing one, discuss the decision with your doctor. AEDs can be expensive and aren't always covered by health insurance.
If you live with someone who is vulnerable to sudden cardiac arrest, it's important that you be trained in CPR. The American Red Cross and other organizations offer courses in CPR and defibrillator use to the public. Being trained will help not only your loved one but also those in your community. The more people who know how to respond to a cardiac emergency, the more the survival rate for sudden cardiac arrest can be improved.
Source: http://www.mayoclinic.com
Because sudden cardiac arrest is so often linked with coronary artery disease, the same factors that put you at risk of coronary artery disease may also put you at risk of sudden cardiac arrest. These include:
Other factors that may increase your risk of sudden cardiac arrest include:
Source: http://www.mayoclinic.com
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