Incidence of Different Types of A-V Block and their Localization by his Bundle Recordings

Atrioventricular block revisited

“…[9][10][11] Yet, many still believe that Type I blocks are all AV nodal, and therefore, basically benign. 12 It is believed that the prognosis of infranodal Type I block is as serious as that of Type II block and a permanent pacemaker is generally recommended in both types regardless of symptoms.…”

Electrocardiographic manifestations: diagnosis of atrioventricular block in the Emergency Department

“…This finding is explained by its association with bundle branch block (20,21). His bundle recordings indicate that the block is never localized to the His bundle; instead, 20% of cases occur in the common bundle and 80% in the bundle branches (5). Consistent with the general rule that blocks distal to the His bundle presume a more serious prognosis, type II blocks often progress to complete heart block (CHB) and produce Stokes-Adams syncope (3,4).…”

Arrhythmias in Children and Young Adults

“…Finally, prolongation of conduction in the infra-Hisian region can be caused by sodium-channel blockers as above. With first degree AV block with a wide QRS complex, conduction in the AV node or the bundle of His is delayed; bilateral bundle branch conduction is slowed in most cases; two levels of conduction delay can also be seen (Peuch et al 1976). …”

“…Mobitz type I (Wenckebach) block occurs at the AV node and His-Purkinje system in a ratio of 3:1, respectively (Peuch et al 1976). Wenckebach phenomenon results from hypervagotonia in athletes and young subjects (Stein et al 2002).…”