Abstract 15430: Comparison of Ventricular Activation Time in Sinus and His Bundle Paced Beats

Abstract

Introduction: The relationship between conduction time of a sinus impulse and a paced impulse from His bundle to peak of left ventricular activation (HVAT) has not been systematically studied. Hypothesis: To perform a comparative analysis of HVAT of sinus and paced impulse in non-selective (NS) His bundle pacing (HBP) and selective (S)-HBP. Furthermore, to determine if pacing voltage and presence of His Purkinje system (HPS) disease affects HVAT. Methods: In 102 consecutive patients a comparative analysis of native HVAT and paced HVAT at higher (5-volt) and lower voltage (1-volt) was done in all patients and in groups subdivided into NS-HBP, S-HBP, with and without HPS disease. Results: Compared to sinus HVAT (105.9 ± 24.0 ms), paced HVAT was shorter at 5-volt (97.2 ± 17.9 ms) ( p<0.01 ) and longer at 1-volt ( p<0.01 ). This voltage effect was significant only in NS-HBP (-15.8 ± 15.7 ms, p<0.01 ) but not in selective-HBP (-6.2± 13.6 ms p=0.16 ). In NS-HBP, decrease in HVAT caused by 5-volt was the same in normal vs diseased HPS (-14.5 ± 12.8 vs-13.2 ±16.3 ms). Conclusions: 1) Compared to sinus HVAT, NS-HBP HVAT is significantly shorter at 5-volt, however, tends to prolong at 1-volt.2) The 1-volt to 5-volt HVAT decrease appears to be similar both normal and diseased NS-HBP thus not related to correction of HPS delay. 3) The voltage related decrease in HVAT is significant in presence of pre-excitation wave seen in NS-HBP and is not significant in S-HBP.