P6020His bundle pacing in patients with abnormal versus intact atrioventricular conduction: from the IMAGE-HBP Study

Abstract Background Frequent right ventricular pacing causes ventricular dyssynchrony and adverse outcomes. His bundle pacing (HBP) offers a physiological alternative. HBP electrical performance characteristics with cardiac conduction system abnormalities are not well established. Purpose To compare HBP implant procedure related parameters in patients with abnormal atrioventricular (AV) conduction versus those with intact AV conduction. Methods Patients prospectively enrolled in the IMAGE-HBP study undergoing implant attempt with a SelectSecure 3830 lead placed at the putative His-bundle location were included in the analysis. Patients were divided into groups based on AV conduction status. Implant characteristics and electrical performance of the pacemaker were tabulated and compared between the two groups with formal statistical tests. Results Among 60 patients (age 74.7 years old and 60% male), 29 patients (48%) had abnormal AV conduction at or below the AV node (18 with AV block of which 5 also had bundle branch block (BBB), 6 with SND and BBB, and 5 with AV node ablation). The remaining 31 patients (52%) had intact AV conduction. Procedure times were not significantly different between the groups (P=0.26). Selective HBP was achieved in 20.7% of abnormal AV conduction patients and 45.2% of intact AV conduction patients (P=0.06); the remaining patients had non-selective HBP. There were no differences detected in pacing characteristics at implant and paced QRS durations by AV conduction status. Patient with intact AV conduction (N=31) Patients with abnormal AV conduction at or below AV node (N=29) Procedure time in minutes (mean ± SD, Median, IQR) 99±38; 87 [43, 180] 108±32; 108 [65, 182] Fluoroscopy time in minutes (mean ± SD, Median, IQR) 15±12; 11 [3, 50] 16±9; 13 [4, 36] Number of fixation attempts 3.0±2.2 2.2±2.0 sHBP PCT N=14 N=6 V at 0.5ms 1.8±0.9 1.7±1.2 V at 1.0ms 1.6±1.2 1.2±0.8 nsHBP PCT N=17 N=22 V at 0.5ms 2.2±1.9 1.7±1.3 V at 1.0ms 1.5±1.1 1.3±1.1 His signal recorded, number 30 (96.8%) 28 (96.6%) H-QRS interval, ms 46±7 48±13 His Injury of Current, N (%) 23 (74.2%) 18 (62.1%) Baseline Intrinsic QRS, ms 96±16 107±22 Paced QRS duration, ms (from HBP at 1.0ms) 119±23 121±19 Conclusions Selective and non-selective HBP are achievable in bradycardic patients with abnormal and intact AV conduction, including those with BBB. There were no major differences in HBP implant parameters between patients with abnormal AV conduction and those with intact