XXII. Intractable paroxysmal tachycardias which proved fatal in type A Wolff-Parkinson-White syndrome.

Abstract

Paroxysmal tachycardias proved fatal in a middle-aged man with type A Wolff-Parkinson-White syndrome. Efforts to control his arrhythmias included a surgical incision into the left atrium, based on discovery of early left ventricular activation during epicardial mapping. The incision did not alter any electrocardiographic or clinical feature; at later necropsy examination it was found that the incision had not cut a nearby left atrioventricular (A-V) connection. Serial section study of the entire A-V rings and septal junction of this heart also demonstrated a second unusual A-V connection, between the atrial septum and the region of the His bundle. This latter connection was anatomically eccentric to the normal organization of this region and may have caused an alteration in the local electrophysiological behavior. The left lateral A-V connection may have been of no electrophysiological significance since it was composed of ordinary working myocardial cells. These and other possible correlations are discussed in the context of the clinical features, numerous electrophysiological observations, and the meticulously determined anatomical findings.

Atrio‐Hisian Fibers Anatomy and Electrophysiology

“…In the reported case there was a rapid supraventricular tachycardia. In an earlier reported case, in which a Kent bundle was also present, a unique supraventricular tachycardia appeared with long and short cycle lengths being sometimes observed in alternation. The electrophysiological recording showed that this alternation involved only the AH interval, since the HV and ventriculoatrial (retrograde) intervals remained constant during bouts of alternating tachycardia.…”

Ventricular Preexcitation in Children and Young Adults

“…8 The second is presence of an atrio-Hisian bundle that bypasses the AV node and transmits the activation signal directly to the His bundle. 22,23 In both substrates, the onset of atrial fibrillation may precipitate ventricular fibrillation as it occurs in the WPW syndrome.…”

“…[23][24][25][26] This fascicle usually is located in the lateral rings and consists of a thin muscular segment that does not possess decremental conduction properties 7 and may serve not only as bypass tract for VP but also as a limb for an AV reentry circuit, which accounts for a reciprocating supraventricular tachycardia. Impedance mismatch between the tiny anomalous fibers and the ventricular muscle bulk in addition to partial replacement of the accessory fascicle by fibrous tissue, as in 1 of our cases, might explain intermittent impaired antegrade conduction.…”