Sudden Cardiac Arrest

Sudden cardiac arrest describes a situation in which the heart abruptly stops beating. Sudden cardiac arrest, or SCA is a medical emergency that requires immediate intervention.

Symptoms of sudden cardiac arrest

The signs and symptoms of cardiac arrest are very clear: a person whose heart suddenly stops beating will quickly lose consciousness and collapse. There will not be a pulse because the heart has stopped pumping. The person will not respond to sounds, voices, or painful stimuli (such as pinching them or rubbing their breastbone hard). When cardiac arrest occurs, the person also stops breathing.

The most common cause of sudden cardiac arrest is an abnormal heart rhythm (arrhythmia). This may mean the heart is beating faster or slower than it should. Even under these circumstances you will likely not find a pulse.

Signs and symptoms of an arrhythmia can come on just before sudden cardiac arrest. They include:

• Feeling dizzy, woozy or light-headed
• Fainting
• Heart palpitations or an irregular heartbeat
• Feeling like your heart is pounding
• Rapid or erratic pulse
• Unusually slow pulse (fewer than 60 beats per minute)
• Shortness of breath

Causes of sudden cardiac arrest

An arrhythmia called ventricular fibrillation is a common cause of sudden cardiac arrest. This occurs when the large chambers of the heart (the ventricles) stop beating rhythmically and instead begin to quiver or flutter. Without a strong contraction by the ventricles, oxygen-rich blood cannot reach the tissues — including the brain and the heart itself. The heart muscle eventually will stop beating.

Ventricular tachycardia, which occurs when the heart beats too fast to sustain a rhythm, also can cause sudden cardiac arrest.

Arrhythmias that induce sudden cardiac arrest can be caused by a variety of factors, including:

• Electrical abnormalities, such as Long QT Syndrome or Wolff-Parkinson-White Syndrome
• Prior heart attack or heart surgery that causes scarring of the cardiac tissue
• Cardiomyopathy (enlarged heart) due to such conditions as heart failure, high blood pressure or heart valve disease
• Side effect of medications used to correct an abnormal heart rhythm
• Severe dehydration or severe electrolyte imbalances
• Drug abuse

Treatment and prevention of cardiac arrest

The treatment and prevention of cardiac arrest depends on the cause. Someone in cardiac arrest may survive with immediate treatment.

Treatment of cardiac arrest includes:

• Calling 911 for emergency medical responders
• Initiating cardiopulmonary resuscitation (CPR)
• Using an automated external defibrillator (AED), if available

To prevent possible cardiac arrest, you should:

• Treat and monitor any known electrical abnormalities of your heart
• Treat and monitor any known heart condition, such as high blood pressure or heart valve disease
• Discuss with your doctor the potential side effects of any medication you take to correct a heart rhythm problem
• Engage in a heart-healthy lifestyle to avoid developing heart failure, which can lead to cardiac arrest
• Obtain a heart examination before competing in sports activities
• Not take illicit drugs