Ventricular Fibrillation

Ventricular fibrillation

Ventricular fibrillation (VF) is a severely abnormal heart rhythm 

(arrhythmia)  that can be life-threatening.

What is ventricular fibrillation?

  The heart beats when electrical signals move through it. 

Ventricular fibrillation  is a condition in which the heart's 
electrical activity becomes disordered. When 

this happens, the heart's lower (pumping) chambers 

contract in a rapid,unsynchronized way. 
(The ventricles "flutter" rather than beat.) 

The heart pumps little or no blood.(AHA)

Causes, incidence, and risk factors

The heart pumps blood to the lungs, brain, and other organs. Interruption of the 

heartbeat for only a few seconds can lead to fainting (syncope) or cardiac arrest.

Fibrillation is an uncontrolled twitching or quivering of muscle fibers (fibrils).

 When it occurs in the lower chambers of the heart, it is called ventricular fibrillation.

 During ventricular fibrillation, blood is not removed from the heart.

Sudden cardiac death results.

The most common cause of VF is a heart attack. However, VF can occur whenever

 the heart does not get enough oxygen or if a person has other heart disorders.

Conditions that can lead to VF include:

• Congenital heart disease
• Electrocution accidents or injury to the heart
• Heart attack
• Heart muscle disease, including cardiomyopathies
• Heart surgery
• Ischemia (lack of oxygen to the heart muscle because of narrowed coronary
   arteries or shock)
• Sudden cardiac death (commotio cordis), typically occurring in athletes after 
  a trauma over the surface of the heart

Most people with VF have no history of heart disease. However, many have risk 

factors for cardiovascular disease, such as smoking, high blood pressure, and diabetes.

Symptoms

A person who has a VF episode will suddenly collapse or become unconscious,

 because the brain and muscles have stopped receiving blood from the heart.

The following symptoms may occur within 1 hour before the collapse:

• Chest pain
• Dizziness
• Nausea
• Rapid heartbeat
• Shortness of breath

Signs and tests

VF is an emergency condition. Seek immediate medical attention.

The pulse in the neck and groin area may be hard or impossible to feel. 

The person will be unresponsive.

The health care provider will listen to the heart with a stethoscope.

 The heartbeats may not be heard, or they may be very irregular.

A cardiac monitor will show a disorganized heart rhythm.

Treatment

Ventricular fibrillation is a medical emergency and must be treated 

immediately to save a person's life.

If a person having a VF episode collapses at home or becomes unconscious,

 call the local emergency number (such as 911).

While waiting for help, place the person’s head and neck in line with the rest

 of the body to help make breathing easier. Start CPR with mouth-to-mouth

 breathing and chest compressions. Continue to do this until the person 

becomes alert or help arrives.

The emergency medical team will quickly examine the person while 

continuing CPR. The person will be taken to the hospital.

VF is treated by delivering a quick electric shock through the chest using 

a device called an external defibrillator. The electrical shock can immediately

 restore the heartbeat to a normal rhythm.

Medicines may be given to control the heartbeat and heart function. People 

with heart muscle damage may need additional procedures,

 including a heart transplant.

A cardiologist will look for potential causes of the VF.

An implantable cardioverter defibrillator (ICD) may be recommended for those 

who survive a VF attack and are at risk for future ones. The ICD can help 

prevent sudden cardiac death.

Moderate hypothermia therapy may be used on people who remain in a

 coma after treatment. This involves keeping the person slightly below normal

 body temperature for several hours. Such therapy has been shown to improve 

the outcome and reduce death.

Expectations (prognosis)

VF can lead to death within a few minutes or a few days. The survival rate for 

a person who has a VF attack outside the hospital ranges between 2% and 25%.

Complications

The most common complication of VF is sudden death (death that occurs 

within 1 hour after symptoms started).

For survivors of VF, complications include:

• Coma
• Nerve problems similar to those after a stroke
• Reduced mental perception