Comparison of Left Ventricular Volumes and Function between His-Bundle and Right Ventricular Pacing

Background: Data suggest that His Bundle pacing (HBP) is superior to right ventricular pacing (RVP) on cardiac structure and function, but evidence is scanty. Objectives We investigated differences between high-burden HBP and RVP on LV volume and function in patients with normal baseline ejection fraction (EF).<br><br>Methods: We studied consecutive patients undergoing HBP attempt, either successful or failed, with baseline EF{greater than or equal to}50% and 6-month ventricular pacing burden {greater than or equal to}20%. Two-dimensional (2D) and three-dimensional (3D) echocardiography were carried out at baseline and after 6 months. <br><br>Results: Among 68 patients who met the inclusion criteria, 40 had successful HBP, and 28 had to go to RVP. The HBP and RVP groups did not differ for age, sex distribution, and pacing indication. At baseline, the HBP and RVP groups did not differ for 2D EF (62% versus 62%), 3D EF (60% versus 63%), 2D (-19% versus -19%) and 3D global longitudinal strain (GLS) (-15% versus -16%). After 6 months, 2D EF (-3.86%) and 3D EF (-5.71%) significantly decreased in the RVP group and did not change in the HBP group (p for interaction 0.006 and &lt;0.001, respectively). 2D GLS (3.08%) and 3D GLS (2.22%) significantly increased in the RVP group, but did not change in the HBP group (p for interaction 0.013 and &lt;0.016, respectively). Pacing induced cardiomyopathy (EF drop {greater than or equal to}10% and EF&lt;50%) occurred in 14% (RVP) versus 0% (HBP) of patients (p=0.025).<br><br>Conclusion: HBP was superior to RVP in preserving LV systolic volume and function and was less often associated with pacing induced cardiomyopathy.