Wolff-Parkinson-White syndrome

Myocardial fibres extending from the atrium to the ipsilateral ventricle across the mitral or tricuspid annulus (accessory pathway) pre-excite the ventricle.

WPW syndrome is restricted to symptomatic patients with a typical ECG abnormality; WPW pattern signifies an asymptomatic patient with typical ECG abnormalities.

Patients often present with atrioventricular re-entrant tachycardia, less commonly atrial fibrillation, and, rarely, sudden cardiac death.

Asymptomatic patients can either be monitored or screened to determine whether they have a 'high-risk' accessory pathway, in which case catheter ablation is typically performed. Screening to determine whether a patient has a high-risk accessory pathway is recommended for patients who have high-risk occupations, such as school bus drivers or pilots, and also for competitive athletes.

Symptomatic patients usually undergo catheter ablation as first-line therapy. Pharmacological therapy can be considered for patients in whom catheter ablation fails and also for patients who prefer a non-invasive approach.

Catheter ablation is highly effective with low risk and can be used either as initial therapy or for patients experiencing side effects or arrhythmia recurrences despite medical treatment.

Occurs when one or more strands of myocardial fibres capable of conducting electrical impulses (known as accessory pathways [APs] or bypass tracts) connect the atrium to the ipsilateral ventricle across the mitral or tricuspid annulus.[1]Vidaillet HJ Jr, Pressley JC, Henke E, et al. Familial occurrence of accessory atrioventricular pathways (preexcitation syndrome). N Engl J Med. 1987 Jul 9;317(2):65-9. http://www.ncbi.nlm.nih.gov/pubmed/3587328?tool=bestpractice.com Conduction from the atrium reaches the adjacent ventricle earlier via the AP, and a part of the ventricle is pre-excited. The term 'Wolff-Parkinson-White (WPW) syndrome' is restricted to symptomatic patients with a typical ECG abnormality, whereas the term 'WPW pattern' signifies an asymptomatic patient with typical ECG abnormalities.[2]Surawicz B, Childers R, Deal BJ, et al. AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram: part III: intraventricular conduction disturbances. Circulation. 2009 Mar 17;119(10):e235-40. http://circ.ahajournals.org/content/119/10/e235.full http://www.ncbi.nlm.nih.gov/pubmed/19228822?tool=bestpractice.com