Key Points
- The aim is to demonstrate electrophysiological evidence of dual A-V nodal pathways in patients with PSVT and normal P-R intervals.
- Electrophysiological recordings were conducted using his bundle recordings and atrial stimulation.
- Refractory periods were measured using the atrial extra-stimulus technique.
- Data from H1-H2 responses were plotted against A1-A2 coupling intervals.
- A critical A1-A2 interval showed a marked increase in H1-H2, indicating the failure of the fast pathway's effective refractory period.
- Shortening of A1-A2 led to defining a second H1-H2 curve, establishing the slow pathway ERP.
- Echo zones coincided with A1-A2 intervals equal to or less than the fast pathway ERP, suggesting conditions for A-V nodal reentry.
Structured PICO
PPopulationn=2 patients with normal P-R interval and reentrant paroxysmal supraventricular tachycardia (PSVT)
IInterventionHis bundle recordings and atrial stimulation using the atrial extra-stimulus technique
OOutcomeElectrophysiological demonstration of dual A-V nodal pathways (dual A-V nodal conduction times and refractory periods)surrogate
This study provides the first electrophysiological demonstration of dual A-V nodal pathways in patients with normal P-R interval and PSVT, establishing a mechanistic basis for AV nodal reentry.