Materials and Methods:
This is a prospective, single center, observational study conducted in
our institute from march 2019 to march 2020 after getting approval from
the institutional ethical committee. Patients provided written informed
consent regarding LBBP as a non-standard approach. All patients aged
between 80-89 years who were planned for permanent pacemaker
implantation for symptomatic bradyarrhythmia and those with left bundle
branch with low left ventricular ejection fraction (LVEF) requiring
cardiac resynchronization therapy (CRT) were included in the study.
Patients who refused for the therapy were excluded.
Intracardiac electrograms along with 12 lead electrocardiography (ECG)
were continuously recorded (Workmate Claris, Abbott, Plymouth, MN). The
procedure was done as described by Huang et al4 using
C315 sheath and 3830 SelectSecuretm lead (Medtronic,
Minneapolis, MN). In brief, the pacing lead was placed deep inside the
septum at a site 1-1.5cm below the His bundle (fig 1A). LB capture was
confirmed by presence of right bundle branch delay pattern (qR in lead
V1) along with any one of the following criteria (a) presence of LB
potential (b) Non-selective to selective LB capture during unipolar
threshold measurement (fig 1B) (c) short and constant peak left
ventricular activation time (pLVAT) <80ms. (d) programmed
stimulation from the pacing lead to show change in QRS morphology,
duration and axis
Patients baseline characteristics and indications for pacing were
documented. ECG, electrophysiological and pacing parameters were
recorded. LVEF was measured by modified simpson’s method. Follow up was
done in device clinic at the end of 15 days, one month and subsequently
every 2 months.