Ashman's phenomenon: a crucial finding to avoid misdiagnosis

Abstract

The Ashman phenomenon, first described in 1947 by Gouaux and Ashman, is an intraventricular conduction aberration that typically occurs during atrial fibrillation and other supraventricular tachyarrhythmias. This phenomenon is characterized by the presence of aberrant QRS complexes, usually with right bundle branch block (RBBB) morphology, resulting from the interaction between consecutive long and short R-R interval cycles. The physiological basis lies in the variability of the relative refractory period of the cardiac conduction system, where a long cycle precedes a short cycle, prolonging the refractory period and favoring aberrant conduction. Ashman's phenomenon can be clinically relevant, as it is often confused with premature ventricular complexes or ventricular tachycardia, which could lead to misdiagnosis and inappropriate therapy.