Wenckebach (type 1) behavior of ventricular reentry.

Electrocardiographic excerpts from three patients demonstrate bigeminy, concealed bigeminy, trigeminy, concealed trigeminy, and Wenckebach's pattern of variation in the coupling interval from sinus beat to ventricular ectopic beat. These diverse manifestations of ventricular ectopy support the hypothesis that reentry in man reflects conduction of an initial impulse, with delay, to cause the coupled reentrant beat.