Alternating Wenckebach periodicity: A common electrophysiologic response
Abstract
Alternating Wenckebach periods are defined as episodes of 2:1 atrioventricular (A-V) block in which conducted P-R intervals progressively prolong, terminating in two or three blocked P waves. In this study, His bundle recordings were obtained in 13 patients with pacing-induced alternating Wenckebach periods. Three patterns were noted: Pattern 1 (one patient with a narrow QRS complex) was characterized by 2:1 block distal to the H deflection (block in the His bundle) and Wenckebach periods proximal to the H deflection, terminating with two blocked P waves. Pattern 2 (four patients) was characterized by alternating Wenckebach periods proximal to the His bundle, terminating with three blocked P waves. Pattern 3 (eight patients) was characterized by alternating Wenckebach periods proximal to the His bundle, terminating with two blocked P waves. Alternating Wenckebach periods are best explained by postulating two levels of block. When alternating Wenckebach periods are terminated by three blocked P waves (pattern 2), the condition may be explained by postulating 2:1 block (proximal level) and type I block (distal level). When alternating Wenckebach periods are terminated by two blocked P waves (patterns 1 and 3), the condition may b...Continue Reading
References
Citations
Two-to-one A-V block with four-to-three A-V nodal wenckebach, a form of spontaneous multilevel block
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