Complex Electrophysiological Characteristics in Atrioventricular Nodal Reentrant Tachycardia With Continuous Atrioventricular Node Function Curves

Background Although typical atrioventricular nodal reentrant tachycardia (AVNRT) with discontinuous AV node function curves has been well studied, there has been a lack of any significant information about AVNRT without evidence of dual AV nodal pathway physiology during atrial extrastimulus testing or atrial pacing. Methods and Results Group 1 included 9 patients with continuous curves during atrial extrastimulus testing but without a jump (≥50 ms) of the atrial–His bundle (AH) interval during incremental atrial pacing. The maximal AH interval during atrial pacing (266±61 versus 168±27 ms, P=.007) or extrastimulus testing (290±60 versus 176±18 ms, P=.005) shortened significantly after ablation. Antegrade and retrograde AV node properties were similar before and after ablation. Group 2 included 14 patients with continuous curves and a jump of the AH interval during incremental atrial pacing. The atrial pacing cycle length with 1:1 AV conduction and effective refractory period (ERP) of the antegrade AV nod...