Dec 1, 1978

Atypical Wenckebach periodicity simulating Mobitz II AV block

British Heart Journal
N El-SherifR Lazzara


Eleven patients were studied and a total of 144 Wenckebach cycles in the AV node and 118 Wenckebach cycles in the His-Purkinje system were analysed to determine the incidence of typical and atypical Wenckebach periodicity, with particular emphasis on one variant of atypical Wenckebach that may simulate a Mobitz type II block. This pseudo-Mobitz II pattern was defined as a long Wenckebach cycle in which, at least, the last three beats of the cycle show relatively constant PR intervals (variation of no more than 0.02 s in surface leads and no more than 10 ms in His bundle electrograms) and in which the PR interval immediately following the blocked beat is shorter than the PR interval before the block by 0.04 s or more. Atypical Wenckebach cycles were found to be more common than the typical variety at both the AV node (67%) and His-Purkinje system (69%). The pseudo-Mobitz II pattern was seen in 19 per cent of atypical AV nodal Wenckebach periods and in 17 per cent of atypical His-Purkinje system Wenckebach cycles. The need to discern a 'classical' Mobitz II block from a pseudo-Mobitz II pattern, especially in the setting of an acute inferior myocardial infarction, is emphasised.

  • References18
  • Citations16


  • References18
  • Citations16


Mentioned in this Paper

Heart Block
Pseudo brand of pseudoephedrine
Differential Diagnosis
Atrioventricular Block
Cardiac Conduction System
Structure of Atrioventricular Node
NODAL gene
Bundle of His
Acute Inferior Myocardial Infarction
Neoplasms, Second Primary

About this Paper

Related Feeds

Cardiac Conduction System

The cardiac conduction system is a specialized tract of myocardial cells responsible for maintaining normal cardiac rhythm. Discover the latest research on the cardiac conduction system here.