Function of Potential Bypass Tracts for Atrioventricular Conduction
Function of potential bypass tracts for the atrioventricular conduction was examined in isolated rabbit hearts using microelectrodes, a suction electrode, and bipolar electrocardiographic leads. After the normal A-V conduction was blocked by acetylcholine, conduction to the ventricle occurred with a much shorter A-V conduction time and without significant QRS change, when a point at the root of the inferior vena cava was stimulated. By analyzing the site of delay, this route was presumed to go from the right atrium to the lower portion of the His bundle bypassing the A-V node. When a point inferior to this point was stimulated, marked shortening of conduction time and marked QRS change occurred. This second tract seemed to exist between the right atrium and ventricle bypassing the specialized system. The third tract was found when an anterior point on the right atrium was stimulated. The conduction was markedly prolonged without changing the QRS. This route seemed to enter some point of the A-V node, inducing a detour within the node.
- Wolff-Parkinson-White syndrome
- Bundle of Kent
- A-V node
- Suction electrode
- Bundle of His
- Mahaim's connections
- Received September 3, 1969.
- Accepted November 11, 1969.
- © 1970 American Heart Association, Inc.