Ventricular fibrillation

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at September 6, 2016
StartDiseasesVentricular fibrillation

The American Heart Association (AHA) states that ventricular fibrillation is a potentially fatal cardiac arrhythmia (irregular heartbeat). The AHA recommends seeking emergency medical attention if a person believes they or someone around them may be suffering from ventricular fibrillation.


Definition & Facts

Ventricular fibrillation is the leading cause of cardiac arrest and it is a type of electrical malfunction of the heart. It is the most common type of arrhythmias, which are the leading causes of cardiac arrest. Because of this, the ventricular fibrillation is sometimes synonymously referred to as sudden cardiac arrest. The survival rate of those with ventricular fibrillation increases the sooner a patient experiencing cardiac arrest attains fibrillation in which a shock of electricity is delivered to the heart to trigger the cardiac cycle, that is, cause the heart to begin beating again.

Symptoms & Complaints

When ventricular fibrillation arises, it progresses very rapidly. When left untreated, death can occur within a few minutes. Initial symptoms include sudden fainting and loss of consciousness. Additional symptoms that signal the onset of ventricular fibrillation include the following:


Ventricular fibrillation can be caused by a wide array of factors. However, in some cases, the cause of onset is completely unknown, in which case it is said to be idiopathic. Some individuals who develop ventricular fibrillation have no prior history of any cardiovascular diseases or conditions. Nonetheless, many known causes and risk factors exist and they include the following:

Diagnosis & Tests

The diagnosis of ventricular fibrillation will always be done on an emergency basis. If emergency treatment is able to be performed and the individual survives, this is typically when a more thorough diagnosis can be made. 

Diagnosing ventricular fibrillation begins by taking a thorough personal medical history and determining a patient's family history. Here, the treating physician will especially look for past family or personal history of risk factors as noted here.

A symptoms list can also be helpful if the individual remembers what symptoms arose just before the onset of ventricular fibrillation. The physician will typically also do a physical examination before ordering any diagnostic tests. There are a number of diagnostic tests that can be helpful in obtaining an accurate diagnosis:

  • EKG (electrocardiogram). This test uses electrodes attached (non-invasively) to the skin's surface to measure the electrical activity happening in the individual's heart. The impulses are recorded to show where anomalies may be occurring.
  • Heart monitor. A heart monitor can be worn to record a longer stretch of the heart's electrical activity. Monitors may be worn for 30 days or more if heart arrhythmias are occasional.
  • Chest X-ray. A chest x-ray can look for anomalies, irregularities or damage to the heart structure and surrounding systems.
  • Echocardiogram. This test directs sound waves at the heart by means of an exterior device called a transducer. The sound waves allow a sonic picture of the heart to be created.
  • Blood tests. Testing the blood can detect certain enzymes known to leak out of the heart and into the bloodstream if there has been a heart attack.
  • Angiogram. Also called coronary catheterization, this test uses an injectable dye to view the arteries for areas that may be narrow or blocked.
  • Magnetic resonance imaging (MRI)a or computed tomography (CT) scans. These medical imaging tests allow physicians to gain a more detailed picture of specific sections of the chest and heart for more accurate diagnosis.

Treatment & Therapy

If one believes he or she or someone near them is suffering from cardiac arrest, they need to call 9-11 immediately. Short-term emergency treatments such as CPR (cardiopulmonary resuscitation) and defibrillation (using electric shock to restart the heart) will need to be applied during the actual episode of ventricular fibrillation.

Later, once the required tests have been done to determine that the issue is ventricular fibrillation, the longer-term treatment phase can begin. Often physicians will prescribe a combination of medications as well as other therapies. The treatment prescribed will depend on the root cause of the ventricular fibrillation.

The medications prescribed to treat ventricular fibrillation are designed to regulate heartbeat to prevent another attack. These drugs include antiarrhythmic agents such as beta blockers, calcium channel blockers, and potassium channel blockers among others.

If there is a narrowing or blockage in the heart's arteries, coronary bypass surgery can work to redirect blood flow in the heart. If there is a more severe blockage, a coronary stent may be inserted to keep the blocked areas open for blood flow. 

Another option is implantation of a device called an ICD (implantable cardioverter-defibrillator) or pacemaker. This device monitors the patient's heartbeat from the inside and sends electrical impulses as needed to stabilize the heart's activity over the long term.

Long-term treatment involves quitting smoking or never starting to smoke or use tobacco to begin with, avoiding secondhand smoke, abstaining from alcohol or drugs (other than those prescribed) as well as adopting a regular exercise plan and a healthy diet.

Prevention & Prophylaxis

Making positive lifestyle adjustments can lower the risks significantly to the extent that ventricular fibrillation is caused by cardiovascular diseases that are, in turn, caused by lifestyle factors like diet and exercise.

Regular exercise, quitting smoking, maintaining a healthy weight, stress management, and seeking help for mental disorders are all important measures in preventing cardiovascular disease.