# Distinct intracardiac electrogram waveforms with perforation during left bundle branch area pacing implantation

## TL;DR

This study examines how intracardiac electrogram waveforms change during perforation during left bundle branch area pacing implantation, identifying distinct patterns that can help detect and manage such complications.

## Contribution

The study introduces systematic waveform analysis to identify perforation during LBBAP implantation, offering new diagnostic criteria based on electrogram morphology.

## Key findings

- Perforation during LBBAP is associated with lower COI amplitude and distinct QS or R/RS waveform morphologies in unipolar iEGMs.
- A sensed Q or S amplitude greater than COI amplitude has high sensitivity and specificity for diagnosing perforation in certain subgroups.
- Macroperforation is marked by significantly lower COI amplitudes, more QS morphology, and fewer sharp multiphasic components compared to microperforation.

## Abstract

Perforation during left bundle branch area pacing (LBBAP) results in a fall in the current of injury (COI) amplitude in the unipolar unfiltered electrogram (iEGM), but systematic waveform analyses have not been performed. Our aim was to investigate unipolar iEGM waveforms during perforation and to compare them to those at the final lead position.

The iEGMS of consecutive patients who had perforation during LBBAP implantation were systematically analysed. A total of 92 patients with perforation were included. In the unfiltered channel, sensed COI amplitude was lower with perforation [3.0 (1.5–4.1) mV] than at the final lead position [14.0 (9.2–17.5) mV, P < 0.0001], as was also the case during pacing. Patients with narrow QRS/non-LBBB typically had wide negative (QS) waveforms during sensing (in 67% of cases), whereas those with LBBB/paced rhythm had positive (wide R/RS) morphologies (in 93% of cases). In the former subgroup, a sensed Q or S amplitude > COI amplitude (which is easy to eyeball during lead deployment) had a sensitivity of 86% and a specificity of 93% for diagnosing perforation. Waveforms during macroperforation (with loss of capture, n = 27) differed compared to microperforation (with preserved capture, n = 65), with significantly lower COI amplitudes, more frequent QS morphology, and rarer sharp multiphasic components in the ventriculogram of the filtered channel.

Beyond COI amplitude, additional iEGM waveform parameters may be used to evaluate the presence of LBBAP perforation and should be carefully monitored during lead deployment to improve safety.

Graphical AbstractWaveforms during left bundle branch area pacing perforation and at final lead position. COI = current of injury; iEGM = intracardiac electrogram; LBBB = left bundle branch block; RVP = right ventricular pacing

Waveforms during left bundle branch area pacing perforation and at final lead position. COI = current of injury; iEGM = intracardiac electrogram; LBBB = left bundle branch block; RVP = right ventricular pacing