Atrioventricular block, second degree

Definition

Second-degree atrioventricular block is composed of 2 types: Mobitz I, which is also named Wenckebach block (and Wenckebach phenomenon), and Mobitz II. The Mobitz I second-degree atrioventricular block (Wenckebach) is characterized by a progressive prolongation of the PR interval, which results in a progressive shortening of the R-R interval. Ultimately, the atrial impulse fails to conduct. The PR interval is the shortest in the first beat in the cycle, while the R-R interval is the longest in the first beat in the cycle. The Mobitz II second-degree atrioventricular block is characterized by an unexpected non-conducted atrial impulse. Thus, the PR and R-R intervals between conducted beats are constant.

Subcategories (1)