Results
Ninety procedures were performed in 87 patients (median age 76 years; 61.1% male): 46 (51.1%) underwent HBP and 44 (48.9%) underwent LBBAP. One patient underwent two HBP implantations and two patients underwent LBBAP after an initial HBP procedure due to lead-related complications. Table 1 exhibits the baseline characteristics of the patients. There were no significant differences between HBP and LBBAP groups in hypertension (HT) (P  < .01), structural heart disease (P  < .05), or sinus atrial rhythm (P  = .05). All patients with wide baseline QRS (n= 49) had a QRS duration of ≥ 130 ms. Left bundle branch potential was recorded in 7 (15.9%) of LBBAP procedures.
A successful outcome was obtained in 85% (77/90) of the implantations, 80.4% (n = 37) in the HBP group and 90.9% (n = 40) in the LBBAP group (P  = .23). Among the thirteen failures, four were in the LBBAP group and nine in the HBP group. The interventricular septum could not be penetrated in all patients in the LBBAP group. In the HBP group, the His electrogram was not recorded in five, there was no QRS reduction in two indicated for CRT, the paced QRS width was > 130 ms (baseline < 120 ms) in one, and effective capture was not achieved in the other. Conventional CRT was performed in seven cases of failure and also in six cases of anti-bradycardia pacing, with the lead being placed in the right ventricle outflow tract in five and kept in the HBP zone in one (QRS 136 ms). The fluoroscopy time was shorter for LBBAP than for HBP (10 vs. 17 min, P  < .001).
In the univariate analysis, a successful outcome was related to age, sex, baseline QRS width, baseline LVEF, and presence of a previous device; none was retained as an independent predictor, but the presence of a previous device was associated with a lower success rate (odds ratio (OR) 5.9; 95% confidence interval (CI) 0.85–42.2;P  = .072).
Similar complication rates were recorded at the three-month follow-up (including complications before hospital discharge) between the HBP group (12.8%, n = 6) and the LBBAP group (6.8%, n = 3) (P  = .48). There were three non-lead-related complications, one in the HBP group (pocket infection) and two in the LBBAP group (subacute pericardial effusion and hematoma). Lead-related complications were more frequent in the HBP group (10.6% vs. 2.3%; P  = .2), with two losses of capture, one displacement, and two significant increases in pacing threshold; there was only one displacement in the LBBAP group (in a patient who had already suffered HBP displacement).