Study limitations
This was a single center study with only 35 patients. We cannot exclude
the possibility that there is a small fraction of patients whom the lead
can be advanced successfully but the left bundle cannot be captured.
LBAP is a relatively new procedure, and success may be limited by
operator experience. In our cohort, the procedures were all performed by
a single experienced operator. The patients where lead advancement was
not achieved were widely distributed in terms of procedure dates, so it
was not due to problems earlier on in the learning curve. The time-order
of cases where lead advancement was not achieved was 5,7,11,29 and 36.
The distribution of our patient cohort is tilted toward a greater extent
of scar because it is from a tertiary center with many cases of advanced
heart failure. However, this does not detract from the observation that
when basal septal scar was extensive, the lead was much less likely to
be advanceable but (once advanced) the left bundle could be successfully
stimulated.
Our center used only one type of lead for the left bundle. We cannot
exclude the possibility that a different type of lead such as a stylet
driven lead may have different advance-ability characteristics.
Nevertheless, there is a clear need for better custom-made tools for
this task.