Comparative study of the surface and endocavitary signals of cardiac pacing system analyzers with respect to the conventional polygraphy systems signals during implantation of conduction system pacing
Authors: Jimenez Lopez J , Carlos Gonzalez Matos C G M , Benjamin Casteigt B C , Oriol Rodriguez Queralto O R Q , Gabriel Martin Sanchez G M S , Sandra Cabrera Gomez S C G , Jaume Francisco Pascual J F P , Jordi Merce Klein J M K , Marcos Rodriguez Garcia M R G , Ignasi Anguera Ramos I A R , Eva Benito Martin E B M , Javier Conejos Montenegro J C M , Emilce Trucco E T , Ermengol Valles Gras E V G 
Published: October 2024

Abstract

Introduction and objectives
Left bundle branch area pacing (LBBAP), is a novel modality of physiologic pacing that requires an adequate assessment of the endocardium as well as the body-surface electrocardiographic signals for a successful pacing-lead implantation. We aimed to assess if LBBAP criteria(1), specifically left ventricular septal pacing (LVSP) and left bundle branch pacing (LBBP) criteria, can be satisfactory measured using the signals resulting from different cardiac pacing analyzers (PSAs) by comparing them to the ‘conventional’ signals obtained from multichannel polygraph systems (MPSs) during the implantation procedure.

Methods
Comparative observational, prospective, multicenter study of consecutive patients who underwent a LBBAP strategy as first intention. LBBP was defined in the presence of a paced QRS with right bundle branch morphology in V1 (initial r wave in lead V1) and at least one of the following criteria:
1. V6-R-Wave Peak Time (RWPT) &lt; 80 ms.
2. V1–V6 interpeak interval &gt; 33 ms.
3. QRS transition from non-selective left bundle branch pacing to selective left bundle branch pacing or NS-LBBP to left ventricular septal pacing during pacing threshold.
4. Sudden increase of V6-RWPT &gt; 15 ms because of reducing pacing output.
5. Left bundle potential-V6RWPT = stim-V6RWPT (±10 ms).
For patients without initial r wave in V1, LBBP was considered in the presence of QRS transition during pacing. LVSP was defined by a paced QRS showing a typical terminal R-wave in V1, anatomical position of the lead in the left ventricular septum documented by fluoroscopy and not fulfilling the additional criteria previously described for LBBP.

Results
63 patients were included. The basal characteristics of the patients are shown in Figure I. No significant differences (p&lt;0.96) were observed in the basal QRS between the MPSs (129±29ms) and the PSAs (129±28ms). Initial "W" morphology in V1 during initial pacing was obtained in 90% of patients, without differences between both measurement systems. There were no significant differences between the MPSs and the PSAs in the paced QRS in V1 (140±10ms vs 141±12ms, p&lt;0.746) nor in V6 (127.4±13ms vs 128.2±14.6ms, p&lt;0.96). The measurement of the R wave peak time (RWPT) in V6 was 78.3±15ms vs 77±14 ms (p&lt;0.72), and the V1-V6 inter-peak was 41.1±16ms in the MPSs vs 39±16 ms the PSAs (p&lt;0.6), respectively, the Pearson correlation coefficients for these last two measurements being 0.91 (p &lt;0.0001) and 0.91 (p &lt;0.0001) (Figure II). Finally, according to electrocardiographic criteria measured by the MPSs, LBBP was achieved in 69% of patients, accomplishing 31% of the patients LVSP criteria, being the same proportions observed when PSAs measures where applied.

Conclusions
The signals resulting from the different PSAs can be useful to assess septal as well as LBBP criteria as an alternative to the ‘conventional’ signals obtained from MPSs.