A Wenckebach periodicity at the mitral isthmus lesion has rarely been
reported. We described a case presenting conduction recovery with
Wenckebach periodicity at the mitral isthmus lesion after achieving the
posterior mitral isthmus block. These findings demonstrate an early
reconnection of mitral isthmus lesion, and an arrhythmogenic substrate
that can lead to development of reentrant tachycardia, that is,
peri-mitral atrial flutter.