Ventricular Fibrillation

Signs and Symptoms

Ventricular fibrillation (VF) is a condition in which the heart's electrical activity becomes disordered. When this happens, the heart's ventricles -- the lower chambers that pump blood -- contract in a rapid, unsynchronized way. The ventricles "quiver" rather than beat, causing the heart to pump little or no blood.

VF is life threatening and requires prompt treatment. Without medical treatment, collapse and sudden cardiac death will occur. However, VF can be treated with a medical device called an implantable cardioverter defibrillator (ICD), which brings the heartbeat back to a regular rhythm.

Diagnosis

Ventricular fibrillation (VF) may occur spontaneously with unpredictable timing and requires specialized tests to acquire an accurate diagnosis. If your doctor suspects that your child has an arrhythmia caused by VF, he or she will order one or more of the following diagnostic tests to determine the source of your child's symptoms:

Electrocardiogram -- An electrocardiogram (ECG or EKG) records the heart's electrical activity. Small patches called electrodes are placed on your child's chest, arms and legs, and are connected by wires to the ECG machine. The electrical impulses of your child's heart are translated into a graph or chart, enabling doctors to determine the pattern of electrical current flow in the heart and to diagnose arrhythmias.

Holter Monitor -- A Holter monitor is a small, portable machine that your child wears for 24 hours. It is about the size of a portable tape player and provides a continuous 24-hour recording of your child's heartbeat onto a tape. You will be asked to keep a diary of your child's activities and symptoms. This monitor may detect arrhythmias that might not show up on a resting electrocardiogram, which only records a heartbeat for a few seconds at rest.

Event Monitor -- This is a small monitor about the size of a pager that your child can have for up to a month. Since the arrhythmia may occur at unpredictable times, this will help to record the abnormal rhythm when your child is experiencing symptoms. He or she can just push a button on the pager and record the heartbeat. The recording can than be transmitted by phone to the doctor.

Exercise Stress Test -- An exercise stress or treadmill test, records the electrical activity of your child's heart during exercise, which differs from the heart's electrical activity at rest.

Electrophysiology Study -- In an electrophysiology (EP) study, doctors insert special electrode catheters -- long, flexible wires -- into veins and guide them into the heart. These catheters sense electrical impulses and also may be used to stimulate different areas of the heart. Doctors can then locate the sites that are causing arrhythmias. The EP study allows doctors to examine an arrhythmia under controlled conditions and acquire more accurate, detailed information than with any other diagnostic test.

Treatment

Treatment for your child's ventricular fibrillation (VF) will depend on the type and severity of their condition and the results of their diagnostic tests, such as the electrophysiology (EP) study. You and your doctor will decide which treatment is right for your child.

Implantable Cardioverter Defibrillator (ICD) -- While not a cure for heart rhythm problems, a defibrillator is a medical device that stops a very fast heart rhythm, brings the heartbeat back to normal and may prevent sudden cardiac death. Defibrillator paddles may either be applied to the chest externally or the defibrillator may be implanted internally, which is known as an internal cardiovertor defibrillator (ICD). An ICD is the most common therapy for children with VF.