[2][3] About 60% of people with the electrical problem developed symptoms,[5] which may include an abnormally fast heartbeat, palpitations, shortness of breath, lightheadedness, or syncope.

[1] The diagnosis of WPW occurs with a combination of palpitations and when an electrocardiogram (ECG) show a short PR interval and a delta wave.

[7] The condition is named after Louis Wolff, John Parkinson, and Paul Dudley White who described the ECG findings in 1930.

[8] Electrical activity in the normal human heart begins when a cardiac action potential arises in the sinoatrial (SA) node, which is located in the right atrium.

[citation needed] The AV node serves an important function as a "gatekeeper", limiting the electrical activity that reaches the ventricles.

[citation needed] Individuals with WPW have an accessory pathway that communicates between the atria and the ventricles, in addition to the AV node.

In some cases, the combination of an accessory pathway and abnormal heart rhythms can trigger ventricular fibrillation, a leading cause of sudden cardiac death.

[9] The bundle of Kent is an abnormal extra or accessory conduction pathway between the atria and ventricles that is present in a small percentage (between 0.1 and 0.3%) of the general population.

The short PR interval and slurring of the QRS complex are reflective of the impulse making it to the ventricles early (via the accessory pathway) without the usual delay experienced in the AV node.

[citation needed] If a person with WPW experiences episodes of atrial fibrillation, the ECG shows a rapid polymorphic wide-complex tachycardia (without torsades de pointes).

[citation needed] When an individual is in normal sinus rhythm, the ECG characteristics of WPW are a short PR interval (less than 120 milliseconds in duration), widened QRS complex (greater than 120 milliseconds in duration) with slurred upstroke of the QRS complex, and secondary repolarization changes (reflected in ST segment-T wave changes).

Individuals with any of these high-risk features are generally considered at increased risk for SCD or symptomatic tachycardia, and should be treated accordingly (i.e.: catheter ablation).

During exercise testing, abrupt loss of pre-excitation as heart rate increases also suggest a lower risk pathway.

[20] According to the ACLS protocol, people with WPW who are experiencing rapid abnormal heart rhythms (tachydysrhythmias) may require synchronized electrical cardioversion if they are demonstrating severe signs or symptoms (for example, low blood pressure or lethargy with altered mental status).

The 2015 ACC/AHA/HRS guidelines recommend beta-blockers or calcium channel blockers as second-line agents, electric cardioversion is reserved for refractory arrhythmias.

[22] People with atrial fibrillation and rapid ventricular response may be treated with amiodarone[7] or procainamide[23] to stabilize their heart rate.

[32] Cardiologists Louis Wolff (1898–1972), John Parkinson (1885–1976) and Paul Dudley White (1886–1973) are credited with the definitive description of the disorder in 1930.