The electrical signal gets bounced around as it moves too quickly from the atrium to the ventricle and back again. This causes the heart to beat too fast. This rapid heart rate is called tachycardia.
A person who has Wolff-Parkinson-White (WPW) syndrome is born with the extra electrical pathway, and symptoms can be experienced at any age.
Periods of tachycardia can cause chest pain, shortness of breath, dizziness, or fainting. In rare instances, it can cause a cardiac arrest. Some people with WPW never have symptoms.
WPW can cause irregular heart rhythms.
The human heart consists of two upper chambers and two lower chambers. The two upper chambers are the left and right atrium. The two lower chambers are the left and right ventricle.
The heart's electrical system signals the heart when to contract. If there is an extra electrical connection inside the heart, it acts as a short circuit, making the heart beat abnormally. It may be too fast or irregular.
If a person has WPW, there is a problem with the communication from the atria to the ventricles. The signal goes around this heart's normal electrical center and causes the ventricle to beat sooner than it should.
WPW affects between 1 to 3 in every 1,000 people.
It is unclear exactly why this extra electrical pathway develops, but a small percentage of patients with WPW have a genetic mutation. Others are born with a heart defect. In infants with WPW about 2 out of 10 have Ebstein's anomaly, which affects the tricuspid valve on the right side of the heart.
The WPW pathway is usually present at birth, but not all infants have symptoms. In infants who have symptoms, there may be rapid breathing, inactivity, poor appetite, listlessness, and rapid heartbeat.
WPW can lead to chest pain and other cardiac symptoms.
Often, the signs and symptoms of WPW will not start until children are older or even in their teens or twenties. Some never have symptoms.
Symptoms can include:
- Dizziness and fainting
- Poor endurance and tiring easily during exercise
Periods of tachycardia can begin rapidly and last for less than a minute, or they can persist for a number of hours.
In more severe cases, the patient can experience:
- Tightness in the chest
- Breathing problems
- Chest pain
- Sudden death.
Some people may feel nothing, and they are unaware that there is a problem.
They may find out that they have WPW when they consult a physician about a different matter.
The type of abnormal rapid rhythm that develops in people with WPW determines how it can best be treated. Some fast rhythms are not life-threatening while others are.
When a patient's heart rate speeds up, the aim of treatment is to slow it down to a normal rate and to prevent recurrence if possible.
Sometimes the rapid heartbeat corrects itself.
A range of treatments is available for people with symptoms of WPW.
Some simple physical movements may help, such as bearing down as if having bowel movement, massaging the sides of the neck over the carotid artery, holding an ice pack on the face, gagging or forceful coughing. These are called vagal maneuvers, because they affect the vagus nerve.
The vagus nerve runs through the body from the abdomen to the brain. A branch of it runs to the heart. When the vagus nerve is stimulated, it can cause a variety of results, depending upon which organ is affected. If the heart is beating too fast, it acts as a brake and slows the heart rate down.
If vagal maneuvers do not work, the doctors may inject the patient with an anti-arrhythmic drug to bring the heartbeat back to normal.
Paddles or patches may be placed on the patient's chest, and an electric shock is applied to the heart, to restore normal heart rhythm.
This type of treatment is known as cardioversion, and it is normally used for patients who have not responded to vagal maneuvers or medication.
Sometimes more invasive procedures are needed to prevent future episodes. A heart specialist can thread a catheter through the blood vessels and up into the heart. At the tips of the catheters are electrodes. By heating these up, it is possible to damage or destroy the extra pathway so that the heart will no longer beat too fast. This procedure is called radiofrequency ablation (RFA).
Some medications may be prescribed to prevent further episodes. Patients who do not want to or who cannot undergo RFA can use these.
Nowadays, RFA has replaced surgery as first-line treatment for WPW. It is simpler and has fewer risks.
However, if a patient needs heart surgery for another issue, the doctor may at the same time destroy the extra electrical pathway surgically.
Those who have WPW but do not have any symptoms typically do not require treatment.