EKG of the Week: Ashman's Phenomenon

Characteristics
Physiologic abberation of a complex on a EKG is called Ashman's Phenomenon and is seen in normal subjects. It occurs when the conduction system does not have time to recover and most commonly occurs in the Right Bundle because it is the segment of the conduction system that has the longest refractory period. Following the Right Bundle Branch the Left Anterior Fascicle is the next most common site of conduction delay resulting in a Left Anterior Hemiblock or a Left Anterior Fascicular Block on EKG. It is usually seen when there is a combination of a long cycle followed by a short cycle as seen above in the ninth complex that conducts with a Right Bundle Branch Block morphology after a long RR interval. See www.askdrwiki.com for more EKGs

References
Ashman R, Byer E:Aberration in the conduction of premature ventricular impulses. J La State Med Soc 8:62, 1946