Characteristics of anterograde conduction over atrio-ventricular junction in patients with paroxysmal reciprocal atrio-ventricular nodal tachycardia

Anterograde conduction over fast and slow pathways was studied in 150 patie nts with paroxysmal reciprocal atrioventricular nodal tachycardia. influenc es of types of atrio-ventricular conduction and other electrophysiological parameters on possibility of initiation of paroxysms of nodal tachycardia a nd their sustainability were also studied. Transesophageal pacing of the he art showed that definite critical relationships between conduction times an d refractory periods of structures constituting re-entry circuit were neces sary for the formation of sustained nodal tachycardia. Parameters of conduc tion time over alternative pathway and values of effective refractory perio ds established in the study allowed to determine criteria of sustainability of paroxysmal reciprocal nodal tachycardia.