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.