A Composite Electrophysiological Descriptor of Atrioventricular Nodal Conduction and Non-inducible Atrioventricular Nodal Reentrant Tachycardia: Findings from a Retrospective Electrophysiological Cohort.

OBJECTIVE: To examine whether a simple electrophysiological descriptor derived from routinely measured antegrade atrioventricular nodal conduction parameters is associated with non-inducible atrioventricular nodal reentrant tachycardia (AVNRT). METHODS: This retrospective cohort included 387 consecutive patients undergoing electrophysiological study for clinically suspected AVNRT. The Total Antegrade Nodal Delay (TAND) index was defined as the sum of the atrio-His (AH) interval and antegrade Wenckebach cycle length (WBCL). Logistic regression, receiver operating characteristic analysis, and quadrant-based continuum analysis were performed. Because WBCL values were missing predominantly in inducible patients, complete-case and sensitivity analyses were conducted. RESULTS: Non-inducible AVNRT occurred in 106 patients (27.4%). In the complete-case TAND cohort (n = 329), higher TAND values were associated with non-inducibility (odds ratio [OR] per 50-ms increase: 1.26, 95% CI: 1.02-1.56, P = .032), remaining significant after adjustment for age and sex (adjusted OR: 1.31, 95% CI: 1.05-1.63, P = .016). Discrimination was modest (area under the curve: 0.592, 95% CI: 0.525-0.659). After multiple imputation, the association remained directionally consistent but was attenuated (adjusted OR: 1.21, 95% CI: 0.99-1.46, P = .056). Quadrant analysis demonstrated a graded increase in non-inducibility from the low-AH/low-WBCL to the high-AH/high-WBCL quadrant (25.0% vs. 42.3%; trend OR: 1.32, 95% CI: 1.07-1.61, P = .008). CONCLUSION: Total Antegrade Nodal Delay was modestly associated with non-inducible AVNRT and may describe a group-level electrophysiological pattern characterized by slower antegrade nodal conduction and higher functional conduction thresholds. However, TAND should not be interpreted as a mechanistic requirement for AVNRT inducibility or as an individual-level prediction tool.