Introduction:We aimed to compare the acute differences in left ventricular (LV) function and mechanical synchrony during nonselective 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 years; males: 75%) were enrolled. There were no differences in LV ejection fraction and GLS between s-HBP and ns-HBP modes: 59% versus 60%, and −15.6% versus −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.

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Background His‐Bundle pacing (HBP) is an emerging technique for physiological pacing. However, its effects on right ventricle (RV) performance are still unknown. Methods We enrolled consecutive patients with an indication for pacemaker (PM) implantation to compare HBP versus RV pacing (RVP) effects on RV performance. Patients were evaluated before implantation and after 6 months by a transthoracic echocardiogram. Results A total of 84 patients (age 75.1±7.9 years, 64% male) were enrolled, 42 patients (50%) underwent successful HBP, and 42 patients (50%) apical RVP. At follow up, we found a significant improvement in RV‐FAC (Fractional Area Change)% [baseline: HBP 34 IQR (31–37) vs. RVP 33 IQR (29.7–37.2),p = .602; 6‐months: HBP 37 IQR (33–39) vs. RVP 30 IQR (27.7–35), p < .0001] and RV‐GLS (Global Longitudinal Strain)% [baseline: HBP –18 IQR (–20.2 to –15) vs. RVP –16 IQR (–18.7 to –14), p = .150; 6‐months: HBP –20 IQR(–23 to –17) vs. RVP –13.5 IQR (–16 to –11), p < .0001] with HBP whereas RVP was associated with a significant decline in both parameters. RVP was also associated with a significant worsening of tricuspid annular plane systolic excursion (TAPSE) (p < .0001) and S wave velocity (p < .0001) at follow up. Conversely from RVP, HBP significantly improved pulmonary artery systolic pressure (PASP) [baseline: HBP 38 IQR (32–42) mmHg vs. RVP 34 IQR (31.5–37) mmHg,p = .060; 6‐months: HBP 32 IQR (26–38) mmHg vs. RVP 39 IQR (36–41) mmHg, p < .0001] and tricuspid regurgitation (p = .005) irrespectively from lead position above or below the tricuspid valve. Conclusions In patients undergoing PM implantation, HBP ensues a beneficial and protective impact on RV performance compared with RVP.

ACM pts present LV concentric hypertrophy and LV systolic and diastolic dysfunction, even in controlled disease. Altered global LV systolic function appears to be due both to longitudinal and radial dysfunction.