What is the role of concealed accessory pathways in the pathogenesis of Wolff-Parkinson-White (WPW) syndrome?

Updated: Jan 08, 2017
  • Author: Christopher R Ellis, MD, FACC, FHRS; Chief Editor: Mikhael F El-Chami, MD  more...
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Some APs are unable to conduct in an antegrade fashion. These are called concealed APs, because "manifest" preexcitation is a delta wave that is visible on a surface 12-lead ECG. (Technically, concealed pathways should not be classifed as a WPW syndrome, because there is no delta wave.) They account for about 30% of all SVTs induced on EPS.

Although no evidence of the pathway is present during sinus rhythm (ie, no preexcitation on ECG), orthodromic tachycardias can occur. Orthodromic tachycardia may also occur when there are two or more accessory connections, and in that case, the retrograde conduction may occur through the AV node, through one of the accessory connections, or through both.

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