Classic Mobitz Type I Second-Degree Atrioventricular Block

Classic Mobitz Type I Second-Degree Atrioventricular Block

The PR interval progressively lengthens with each beat until the atrial impulse is not conducted and the QRS complex is dropped (Wenckebach phenomenon); atrioventricular nodal conduction resumes with the next beat, which has the shortest PR interval, and the sequence is repeated.