Your heart is a muscle that pumps blood through your body. Your heart rate is how fast your heart beats. Your heart should always have a regular, rhythmic beat, like the ticking of a clock.
Your heart has four chambers. The atria are the two upper chambers in your heart. The ventricles are the two lower chambers in your heart. The atria pump blood to the ventricles. The ventricles pump blood to your lungs and your body (see also Biology of the Heart Biology of the Heart The heart is a hollow organ made of muscle. The heart and blood vessels are part of your cardiovascular system. Your heart pumps blood through your blood vessels Blood carries oxygen and nutrients... read more ).
Special pacemaker cells in a part of the atria called the SA node (sinoatrial node) send out regular electrical signals to your heart muscle to make it contract.
Your heart's conduction system has tiny strips of tissue sort of like electrical wires. The conduction system carries the pacemaker signals to the rest of your heart. The signals must get to all your heart muscle cells at just the right time so your heart gives a good, strong beat that pumps blood properly.
What is Wolff-Parkinson-White (WPW) syndrome?
WPW syndrome is an abnormal heart rhythm Overview of Abnormal Heart Rhythms Your heart is a muscle that pumps blood through your body. Your heart rate is how fast your heart beats. Your heart should always have a regular, rhythmic beat, like the ticking of a clock.... read more 
that causes your heart to beat too quickly. It's a condition you're born with that involves an extra, abnormal electrical path in your heart. When triggered, the extra path causes a rapid heart rate.
Even though you're born with the extra electrical path, symptoms don't usually start until you're in your teens or early 20s
Doctors treat WPW syndrome with medicines and other measures
What are the symptoms of WPW syndrome?
Symptoms usually start in your teens or early 20s, but they can start at any age.
In babies, symptoms may include:
Breathing problems
Acting overly tired
Not eating well
In teens and adults, symptoms may include:
Feeling your heart racing
Sometimes fainting
Sometimes chest pain
Another abnormal heart rhythm disorder called atrial fibrillation Atrial Fibrillation and Atrial Flutter Your heart is a muscle that pumps blood through your body. Your heart rate is how fast your heart beats. Your heart should always have a regular, rhythmic beat, like the ticking of a clock.... read more is a very dangerous for people with WPW syndrome. The combination of atrial fibrillation and WPW can lead to ventricular fibrillation Ventricular Fibrillation Ventricular fibrillation is a potentially fatal, uncoordinated series of very rapid, ineffective contractions of the ventricles (lower chambers of the heart) caused by many chaotic electrical... read more 
, which is fatal unless treated immediately.
How can doctors tell if I have WPW syndrome?
Doctors feel your pulse and do:
An ECG is a quick, painless test that measures your heart’s electrical activity using stickers and cables on your chest, arms, and legs.
How do doctors treat WPW syndrome?
To slow your heart rate, your doctor may ask you to try one of the following:
Strain as if having trouble passing stool
Rub your neck just below the angle of your jaw
Plunge your face into a bowl of ice-cold water
If these don't work or you're having severe symptoms, doctors will:
Give you medicine directly into your vein (IV medicine)
If you keep having episodes of rapid heart rate from WPW, doctors may recommend:
An ablation procedure
What's an ablation procedure?
Doctors first do electrophysiologic testing, which is like cardiac catheterization Cardiac Catheterization Cardiac is a medical term for the heart. Catheterization means to put a thin, hollow tube (catheter) into some part of your body. So in cardiac catheterization (cardiac cath): Your doctor puts... read more 
. Doctors insert a thin flexible tube (catheter) into a large blood vessel (for example, in your leg) and thread it up to your heart. The catheter has electrodes on its tip that record your heart's electrical activity from the inside. The catheter can also stimulate your heart electrically to see how it responds.
If the test shows that one small bit of heart tissue is causing the WPW, getting rid of the tissue often fixes the rhythm problem. Doctors use a catheter that delivers a high-frequency electrical current to destroy the tissue that's causing the problem.
