[Analysis of Luciani-Wenckebach periodism in A-V node. I. Typical features (author's transl)].

Electrocardiograms of 20 patients developing Wenckebach A-V block duting atrial pacing and 20 with spontaneous Wenckebach block were reviewed to determine the frequency of typical features of classical Wenckebach periodicity. Few cases only met all six typical criteria. Cases with long cycles with conduction ratios of 5/4, with Wenchkebach point less than 130 min, and with first greater than A-H 110 msec were the most likely to show typical features. The implications of these observations are discussed on the basis of modern hypothesis of electrophysiological mechanisms of Wenckebach periodism.