Wolff-Parkinson White Syndrome
Wolff-Parkinson-White Syndrome (WPWS) is a disorder in which an extra electrical connection between the atria and the ventricles is present at birth. People may have episodes of a very rapid heartbeat.
People with WPWS are born with an extra connection in the heart, called an accessory pathway, that allows electrical signals to bypass the trioventricular node and move from the atria to the ventricles faster than usual. The accessory pathway may also transmit electrical impulses disrupt the coordinated movement of electrical signals through the heart, abnormally from the ventricles back to the atria. This extra connection can leading to an abnormally fast heartbeat (tachycardia) and other arrhythmias.
The heartbeat is controlled by electrical signals that move through the heart in a highly coordinated way. A specialized cluster of cells called the atrioventricular node conducts electrical impulses from the heart's upper chambers (the atria) to the lower chambers (the ventricles). Impulses move through the atrioventricular node during each heartbeat, stimulating the ventricles to contract slightly later than the atria.
WPWS is the most common of several disorders that involve an extra (accessory) pathway between the atria and the ventricles. (Such disorders are called atrioventricular reciprocating supraventricular tachycardias.) This extra pathway makes fast arrhythmias more likely to occur. WPW syndrome changes the pattern of electrical activation in the heart and can be diagnosed using electrocardiography.
Atrial fibrillation may be particularly dangerous for people with Wolff-Parkinson-White syndrome. The extra pathway can conduct the rapid impulses to the ventricles at a much faster rate than the normal pathway (through the atrioventricular node) can. The result is an extremely fast ventricular rate that may be life threatening. Not only is the heart very inefficient when it beats so rapidly, but this extremely fast heart rate may also progress to ventricular fibrillation, which is fatal unless treated immediately.
Symptoms may include dizziness, a sensation of fluttering or pounding in the chest (palpatations), shortness of breath, and fainting (syncope). In rare cases, arrhythmias associated with Wolff-Parkinson-White syndrome can lead to cardiac arrest and sudden death. The most common arrhythmia associated with Wolff-Parkinson-White syndrome is called paroxysmal supraventricular tachycardia.. Very rarely, this syndrome results in a very fast, life-threatening heart rate during atrial fibrillation.
WPWS is present at birth, but the arrhythmias it causes usually become apparent during the teens or early twenties. However, arrhythmias may occur during the first year of life or not until after age 60.
When infants develop arrhythmias due to this syndrome, they may become short of breath or lethargic, stop eating well, or have rapid, visible pulsations of the chest. Heart failure may develop.
Typically, when teenagers or people in their early 20s first experience an arrhythmia due to this syndrome, it is an episode of palpitations that begins suddenly, often during exercise. The episode may last for only a few seconds or may persist for several hours. For most people, the very fast heart rate is uncomfortable and distressing. A few people faint.
In older people, episodes of paroxysmal supraventricular tachycardia due to Wolff-Parkinson-White syndrome tend to produce more symptoms, such as fainting, shortness of breath, and chest pain.
The Cleveland Clinic Heart Center http://www.clevelandclinic.org/heartcenter/pub/guide/disease/electric/wpw.htm