Answer to the question on 10.04.2015
Accessory pathways are anomalous bypass tracts composed of working myocardial cells. Most APs insert along the mitral or tricuspid valve and are referred to as AV accessory pathways. Approximately 60% of APs insert along the mitral valve and are referred to as left free-wall pathways. About 25% insert along the septal aspect of the tricuspid or mitral valve and are classified as septal pathways. The remaining 15% are right freewall pathways.
Occasionally one may encounter APs that do not insert along the AV valves. Examples include atriofascicular, nodoventricular, nodofascicular, and atrionodal pathways.
Atriofascicular pathways connect the right atrium to the distal ramifications of the right bundle branch and are capable of only anterograde conduction.
Nodoventricular and nodofascicular pathways connect the AV node to the right ventricular myocardium and the specialized conduction system, respectively.
Atriofascicular and nodoventricular/nodofascicular connections are also notable for their decremental conduction properties.
Atrionodal pathways are rare and connect the right atrial myocardium to the AV node.
(Ref: Cardiac Electrophysiology: From Cell to Bedside: 6th edition, Page : 755)
Q. Localize the accessory pathway (AP) from the ECG
A. Left free wall AP
B. Posteroseptal AP
C. Right free wall AP
D. Anteroseptal AP
Please post your answers as comments.
Keywords: Cardiology, Multiple choice questions, medical students, Electrophysiology