Pacing and ECG characteristics during LBBAP
Pacing and ECG characteristics are summarized in Table 2. Implant pacing
thresholds were low and comparable between the SDL and LLL group
(unipolar pacing threshold 0.5±0.15 versus 0.4±0.17V at 1.0ms pulse
width, p=0.251). Sensing values and lead impedances were comparable
between both groups.
Paced QRS duration was 127±20.3ms in the SDL group compared to
131±23.6ms in the LLL group, p=0.570). Stimulus to LVAT measured
73±15.2ms in the SDL group compared to 71±11.2ms in the LLL group
(p=0.703). In patients with narrow QRS, paced QRS duration increased
significantly from 98±15.9ms to 121±17.7ms (p=0.005) with LBBAP, whereas
in patients with left bundle branch block (LBBB) QRS duration decreased
significantly from 170±16.7ms to 126±26.3ms (p= 0.011) with LBBAP.
Changes in QRS duration for both narrow QRS and LBBB patients were
comparable for SDL and LLL. LBBp were observed in 38% of the SDL
patients compared to 13% of the LLL patients (p=0.198).