<prompt> WPW syndrome is caused by -Bundle Branch BlockRight sided accessory pathwayEctopic pacemaker in atriumLeft budle Branch block  <response>: Ans. is b i.e., Right sided accessory pathwayAnatomy Location of Accessory pathway in W.P.W. syndromeo Electrophysiological studies and mapping have shown that accessory. Atrioventricular pathways may be located anywhere along the A-V rign or groove in the septum.o The most frequent locations are:- Left lateral 50, posteroseptal 30 right anteroseptal 10. Right lateral 10.o Preexcitation resulting from left sided accessory is called type A preexcitation.o Preexcitation resulting from right sided accessory pathway is called type B preexcitation. 