Non-selective versus selective His bundle pacing: an acute intrapatient speckle tracking strain echocardiographic study.

INTRODUCTION We aimed to compare the acute differences in left ventricular (LV) function and mechanical synchrony during non-selective His bundle pacing (ns-HBP) versus selective His bundle pacing (s-HBP) using strain echocardiography. METHODS AND RESULTS Consecutive patients with permanent His bundle pacing, in whom it was possible to obtain both s-HBP and ns-HBP, were studied in two centers. In each patient echocardiography was performed sequentially during s-HBP and ns-HBP. Speckle tracking echocardiography parameters were analyzed: global longitudinal strain (GLS), the time delay between peak systolic strain in the basal septal and basal lateral segments (BS-BL delay), peak strain dispersion (PSD) and strain delay index. Right ventricle function was assessed using tricuspid annular plane systolic excursion (TAPSE) and tissue Doppler velocity of the lateral tricuspid annulus (S'). A total of 69 patients (age: 75.6 ± 10.5; males: 75%) were enrolled. There were no differences in LV ejection fraction and GLS between s-HBP and ns-HBP modes: 59% vs. 60%, and -15.6% vs. -15.7%, respectively; as well as no difference in BS-BL delay and strain delay index. The PSD value was higher in the ns-HBP group than in the s-HBP group with the most pronounced difference in the basal LV segments. No differences in right ventricular function parameters (TAPSE and S`) were found. CONCLUSION The ns-HBP and s-HBP modes seem comparable regarding ventricular function. The dyssynchrony parameters were significantly higher during ns-HBP, however, the difference seems modest and clarification of its impact on LV function requires a larger long term study. This article is protected by copyright. All rights reserved.