Abstract
Background
Left bundle area pacing is growing in use both for bradycardia pacing
and cardiac resynchronization, but implants are not always successful.
We prospectively studied consecutive patients to determine whether
septal scar contributes to implant failure.
Methods
Patients scheduled for left bundle area pacing, using the 3830
Selectsecure lead were prospectively enrolled. All patients underwent
standardized scar assessment by cardiac MRI with late gadolinium
enhancement imaging. Scar burden was quantified as the proportion of
basal septal segments showing late enhancement.
Results
35 patients were recruited: 29 male, mean age 68 years, 10 with ischemic
and 16 with dilated cardiomyopathy. Pacing indication was bradycardia in
26% and cardiac resynchronization in 74%.
In 5/35 (14%) it was not possible to advance the lead through the
ventricular septum. Basal septal late gadolinium enhancement was
significantly more extensive in these patients (median 67%, IQR
58-69.5) compared to the other 30 (median 10%, IQR 0-20, p = 0.0006).
There was no significant correlation between the paced QRS duration
achieved and the extent of basal septal scar (r = 0.06, P = 0.75).
Conclusions
Failure to deliver a lead to the left bundle area is strongly associated
with a (very) high burden of scar in the basal septum. Once the lead is
delivered, however, the electrical response is independent of scar
burden. This suggests that it would be worth developing delivery tools
to tackle scarred basal septa, because if the lead could be delivered
the electrical capture might still achieve a narrow QRS.