Variant Preexcitation Syndrome: A True Nodoventricular Mahaim Fiber or an Accessory Atrioventricular Pathway with Decremental Properties?

Abstract

The finding that the S-Delta interval could become shorter than the A2HB-Delta interval provides strong evidence that this accessory pathway was not connected to the AV node but arose directly from the atrial tissue of the posteroseptal region.

Ebstein's Anomaly in Adults.Arrhythmias: Diagnosis and Therapeutic Approach

“…The vast majority of these patients never show episodes of narrow QRS complex tachycardia due to the absence of retrograde conduction of the accessory pathway (Aliot). Recent investigations have identified these fibers consisting of AV-node-like specific conduction tissue, originating in case of atriofascicular or atrioventricular connections mainly from the posterior to lateral aspect of the tricuspid valve [1,4,23]. During sinus rhythm, typical patterns of preexcitation may be absent due to the slow conduction properties of the fiber.…”