Wolff-Parkinson-White syndrome (WPW)
Preexcitation syndrome; WPW; Tachycardia - Wolff-Parkinson-White syndrome; Arrhythmia - WPW; Abnormal heart rhythm - WPW; Rapid heartbeat - WPW
Wolff-Parkinson-White (WPW) syndrome is a condition in which there is an extra electrical pathway in the heart that leads to periods of rapid heart rate (tachycardia).
WPW syndrome is one of the most common causes of fast heart rate problems in infants and children.
The atria, and their respective ventricles, are electrically insulated from each other by a fibrous tissue known as the atrioventricular (AV) junction. Impulses are transferred via a special bridge, called the His-Purkinje system (HPS). Some individuals, however, have additional bridges called accessory pathways. Irregular heartbeats resulting from impulses passing through accessory pathways are called supraventricular. Supraventricular tachycardias (SVT) may be atrial or AV junctional. In atrial tachycardia, the impulse arises from the superior portion of either atrium. This condition may arise when the tissues of the atria or pericardium, the membrane covering the heart, are affected by a chronic or acute inflammation, dilation or enlargement of an atrium, or formation of reparative tissue called fibrosis. Re-entry tachycardias result from congenital accessory pathways, and can be manifested at any age. AV nodal re-entry (AVNR) is the most common AV junctional tachycardia. The re-entry circuit is localized in the AV node, a small node involved in the conduction system of the heart. AV nodal re-entry results from differences in conducting fibers leading to divergence in impulses. Wolff-Parkinson-White syndrome is one of the most frequently encountered accessory pathway syndromes. The incidence is approximately 150 cases per year per 100,000 individuals. Electrical impulses bypass the AV node and travel along the bundle of Kent accessory pathway instead. This results in ventricular pre-excitation, because the impulse reaches the ventricle prematurely. Very rapid heartbeats, a complication of Wolff-Parkinson-White, can result in severe hypotension and syncope, or loss of consciousness.
Ebstein's anomaly is a congenital heart condition which results in an abnormality of the tricuspid valve. In this condition the tricuspid valve is elongated and displaced downward towards the right ventricle. The abnormality causes the tricuspid valve to leak blood backwards into the right atrium.
During a heart Holter monitor study, the patient wears a monitor that records electrical activity of their heart (similarly to the recording of an electrocardiogram). This usually occurs for 24 hours, while at the same time the patient also records a diary of their activity. Health care providers then analyze the recording, tabulate a report of the heart's activity, and correlate irregular heart activity with the entries of the patient's diary.
The intrinsic conduction system sets the basic rhythm of the beating heart by generating impulses which stimulate the heart to contract.
The atria, and their respective ventricles, are electrically insulated from each other by a fibrous tissue known as the atrioventricular (AV) junction. Impulses are transferred via a special bridge, called the His-Purkinje system (HPS). Some individuals, however, have additional bridges called accessory pathways. Irregular heartbeats resulting from impulses passing through accessory pathways are called supraventricular. Supraventricular tachycardias (SVT) may be atrial or AV junctional. In atrial tachycardia, the impulse arises from the superior portion of either atrium. This condition may arise when the tissues of the atria or pericardium, the membrane covering the heart, are affected by a chronic or acute inflammation, dilation or enlargement of an atrium, or formation of reparative tissue called fibrosis. Re-entry tachycardias result from congenital accessory pathways, and can be manifested at any age. AV nodal re-entry (AVNR) is the most common AV junctional tachycardia. The re-entry circuit is localized in the AV node, a small node involved in the conduction system of the heart. AV nodal re-entry results from differences in conducting fibers leading to divergence in impulses. Wolff-Parkinson-White syndrome is one of the most frequently encountered accessory pathway syndromes. The incidence is approximately 150 cases per year per 100,000 individuals. Electrical impulses bypass the AV node and travel along the bundle of Kent accessory pathway instead. This results in ventricular pre-excitation, because the impulse reaches the ventricle prematurely. Very rapid heartbeats, a complication of Wolff-Parkinson-White, can result in severe hypotension and syncope, or loss of consciousness.
Causes
Normally, electrical signals follow a certain pathway through the heart. This helps the heart beat regularly. This prevents the heart from having extra beats or beats happening too soon.
In people with WPW syndrome, some of the heart's electrical signals go down an extra pathway. This may cause a very rapid heart rate called supraventricular tachycardia.
Most people with WPW syndrome do not have any other heart problems. However, this condition has been linked with other cardiac conditions, such as Ebstein anomaly. A form of the condition also runs in families.
Symptoms
How often a rapid heart rate occurs varies depending on the person. Some people with WPW syndrome have only a few episodes of rapid heart rate. Others may have the rapid heart rate once or twice a week or more. Also, there may be no symptoms at all, so that condition is found when a heart test is done for another reason.
A person with this syndrome may have:
- Chest pain or chest tightness
- Dizziness
- Lightheadedness
- Fainting
- Palpitations (a sensation of feeling your heart beating, usually quickly or irregularly)
- Shortness of breath
Exams and Tests
A physical exam done during a tachycardia episode will show a heart rate faster than 100 beats per minute. A normal heart rate is 60 to 100 beats per minute in adults, and under 150 beats per minute in newborns, infants, and small children. Blood pressure will be normal or low in most cases.
If the person is not having tachycardia at the time of the exam, the results may be normal. The condition may be diagnosed with an electrocardiogram (ECG) or with ambulatory ECG monitoring, such as a Holter monitor.
A test called an electrophysiologic study (EPS) is done using catheters that are placed in the heart. This test may help identify the location of the extra electrical pathway.
Treatment
Medicines, particularly antiarrhythmic drugs such as procainamide or amiodarone, may be used to control or prevent a rapid heartbeat.
If the heart rate does not return to normal with medical treatment, health care providers may use a type of therapy called electrical cardioversion (shock).
The long-term treatment for WPW syndrome is very often catheter ablation. This procedure involves inserting a tube (catheter) into a vein through a small cut near the groin up to the heart area. When the tip reaches the heart, the small area that is causing the fast heart rate is destroyed using a special type of energy called radiofrequency or by freezing it (cryoablation). This is done as part of an electrophysiologic study (EPS).
Before ablation is considered, you may be asked to undergo an exercise stress test to help decide if you need ablation.
Open heart surgery to burn or freeze the extra pathway may also provide a permanent cure for WPW syndrome. In most cases, this procedure is done only if you need heart surgery for other reasons.
Outlook (Prognosis)
Catheter ablation cures this disorder in most people. The success rate for the procedure ranges between 85% to 95%. Success rates will vary depending on the location and number of extra pathways.
Possible Complications
Complications may include:
- Complications of surgery
- Heart failure
- Reduced blood pressure (caused by rapid heart rate)
- Side effects of medicines
The most severe form of a rapid heartbeat is ventricular fibrillation (VF), which will rapidly lead to shock or death unless it is corrected. It can sometimes occur in people with WPW, particularly if they also have atrial fibrillation (AF), which is another type of abnormal heart rhythm. This type of rapid heartbeat requires emergency treatment and a procedure called cardioversion.
When to Contact a Medical Professional
Contact your provider if:
- You have symptoms of WPW syndrome.
- You have this disorder and symptoms get worse or do not improve with treatment.
Talk to your provider about whether your family members should be screened for inherited forms of this condition.
References
Dalal AS, Van Hare GF. Disturbances of rate and rhythm of the heart. In: Kliegman RM, St. Geme JW, Blum NJ, Shah SS, Tasker RC, Wilson KM, eds. Nelson Textbook of Pediatrics. 21st ed. Philadelphia, PA: Elsevier; 2020:chap 462.
Kalman JM, Sanders P. Supraventricular Tachycardias. In: Libby P, Bonow RO, Mann DL, Tomaselli GF, Bhatt DL, Solomon SD, eds. Braunwald's Heart Disease: A Textbook of Cardiovascular Medicine. 12th ed. Philadelphia, PA: Elsevier; 2022:chap 65.
Zimetbaum P, Goldman L. Supraventricular ectopy and tachyarrhythmias. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 52.
Version Info
Last reviewed on: 2/27/2024
Reviewed by: Thomas S. Metkus, MD, Assistant Professor of Medicine and Surgery, Johns Hopkins University School of Medicine, Baltimore, MD. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
