Transverse Dissociation of the Human His Bundle

“Completed” and “abor tive” alternating Wenckebach periods occurred in a symptomatic female with calcification of the mi tral annulus, These arrhythmias were attributed to transverse dissociation of the His bundle into two horizontal levels “connected in series,” with 2:1 block in the “distal” level and Wenckebach periods in the “proximal” level. Intra‐Hisian alternating Wenckebach periods resembled those resulting from transverse dissociation of other infra‐AV nodal structures in that they are rare, usually symptomatic and require pacemaker implantation. This contrasts with the variety of rhythms resulting from trans verse dissociation of the AV node which occur frequently, are not always malignant, and generally are not treated with implanted pacemakers. (PACE, Vol. 5, May‐June, 1982)