Baseline characteristics
Patients underwent pacemaker implantation for sick sinus syndrome, high degree atrioventricular block, complete heart block and/or cardiac resynchronization therapy. There were no significant differences amongst indications in HBP vs LBBAP groups. Equal numbers of patients in both groups (20%) developed indications for pacing following transcatheter aortic valve replacement. Patients undergoing HBP were younger than those who underwent LBBAP (73.2±15.3 vs 78.2±9.2 years, p = 0.047). Though there was a non-significant trend towards more patients in the HBP group with ischemic or non-ischemic cardiomyopathy, the HBP group had a lower LV ejection fraction compared to the LBBAP group (51.0±15.9 vs 57.0±13.1%, p = 0.044). There was no significant difference between pre-procedural intrinsic QRS width (135.4±29.1 vs. 131.0±34.6 ms, p = 0.505), incidence of right bundle branch block or left bundle branch block (37.5 vs. 42.0%, p = 0.649; 25.0 vs. 22.0%, p = 0.726) between groups (Table 1 ).