Abstract

BACKGROUND: The post-pacing interval (PPI) minus the tachycardia cycle length (TCL) is frequently used to investigate tachycardias. However, a variety of issues (e.g. failure to entrain, decremental conduction, and oscillating TCLs) can make interpretation of the PPI-TCL challenging.OBJECTIVES: To investigate a novel maneuver to confirm the PPI-TCL value without using either the ventricular PPI or the TCL interval. To assess the ability of this maneuver to identify decremental conduction and differentiate supraventricular tachycardias.METHODS: We analyzed 77 intracardiac recordings from patients [age 25±20 years, 40 female] who underwent catheter ablation of AVNRT or orthodromic reciprocating tachycardia (ORT) with a concealed pathway. We calculated the PPI-TCL, the AH-corrected PPI-TCL, and estimated the PPI-TCL using "dual chamber entrainment" calculated as: [PPIV-TCL=Stim(AoV)+Stim(VoA)-PPIA].RESULTS: The PPI-TCL calculated by dual chamber entrainment highly correlated with the observed and AH-corrected PPI-TCL [R2=0.79 and 0.96, respectively, p<0.001]. A dual chamber entrainment PPI-TCL value of 80ms correctly differentiated all AVNRT from septal ORT cases, whereas the standard PPI-TCL and AH-corrected PPI-TCL methods were incorrect in 14% and 6% of cases, respectively. Dual chamber entrainment identified 3±10ms of additional decremental conduction beyond AH-prolongation, including four pathways with significant (>10ms) decrement.CONCLUSION: Dual chamber entrainment estimates the PPI-TCL value without using either the ventricular PPI or the TCL interval. This maneuver adjusts for all decremental conduction, including within concealed pathways, where a dual chamber entrainment PPI-TCL value >80ms favors AVNRT over ORT. This maneuver can be used to verify the observed PPI-TCL value in challenging cases.

View details for PubMedID 30465902