Distinctive characteristics of his bundle potentials in patients with atrioventricular nodal reentrant tachycardia

Background: His bundle (HB) potentials vary in amplitude and duration in patients with and with-out slow pathways. The aim of this study was to determine the characteristics of HB potentials and to elucidate whether they can provide clues for identification of slow pathway (SP). Methods: The present research prospectively studied the electrophysiological findings of 162 patients with symptomatic atrioventricular nodal reentrant tachycardia (AVNRT) due to slow-fast or fast-slow type and atrioventricular reentrant tachycardia (AVRT). Maximal HB potential (HBmax, HB with the highest amplitude) among HB cloud was recorded in both groups. For AVNRT patients, the following were measured: (1) AH interval at the jump during programmed atrial stimulation (A2H2, taken as a reflection of SP conduction time); (2) Distance from HBmax to the successful SP ablation site (HBmax-ABL) and from HBmax to the ostium of coronary sinus (HBmax-CSO). Results: HBmax was 0.29 +/- 0.10 mV in AVNRT patients, whereas it was 0.17 +/- 0.05 mV in AVRT group (p < 0.0001). Likewise, the HBmax duration was 22 +/- 5 ms in AVNRT group and 16 +/- 3 ms in AVRT group (p < 0.0001). The area under the receiver operating characteristic curve of HBmax amplitude in AVNRT patients was 0.86 and the optimal HBmax cut-off to predict AVNRT was >= 0.22 mV with a sensitivity of 0.78 and specificity of 0.84. HBmax-CSO was positively correlated with HBmax-ABL, and HBmax-ABL was positively correlated with A2H2. Conclusions: HBmax amplitudes were higher and durations longer in patients with AVNRT, as com-pared to those with AVRT. Moreover, the distance between HBmax and successful ablation site was posi-tively correlated with the SP conduction time and with the distance from HBmax to the CSO. (Cardiol J)

Automated summary

This study aimed to investigate the characteristics of His bundle potentials in patients with symptomatic atrioventricular nodal reentrant tachycardia (AVNRT) and to determine whether they can provide clues for the identification of slow pathway (SP). The study found that the amplitude and duration of HBmax were higher and longer, respectively, in patients with AVNRT compared to those with atrioventricular reentrant tachycardia (AVRT).