This report described initiation of A-V nodal reentrant tachyycardia in a patient with acute inferior myocardial infarction. The onset of tachycardia was preceded by an abortive A-V nodal Wenckebach periodicity. A-V nodal ischemia with or without vagotonia was implicated as the cause of induction of critical functional dissociation between the two A-V nodal conduction pathways. Since the tachycardia manifested its rate between 95-110 beats/min during the evolutionary phase of acute inferior myocardial infarction, it simulated, electrocardiographically, an accelerated A-V junctional rhythm. Analysis of the onset of tachcardia was of diagnostic importance.