A randomized comparison of HBP versus RVP: Effect on left ventricular function and biomarkers of collagen metabolism.

BACKGROUND: Right ventricular pacing (RVP) can result in pacing-induced cardiomyopathy (PICM). It is unknown whether specific biomarkers reflect differences between His bundle pacing (HBP) and RVP and predict a decrease in left ventricular function during RVP. AIMS: We aimed to compare the effect of HBP and RVP on the left ventricular ejection fraction (LVEF) and to study how they affect serum markers of collagen metabolism. METHODS: Ninety-two high-risk PICM patients were randomized to HBP or RVP groups. Their clinical characteristics, echocardiography, and serum levels of transforming growth factor ß1 (TGF-ß1), matrix metalloproteinase 9 (MMP-9), suppression of tumorigenicity 2 interleukin (ST2-IL), tissue inhibitor of metalloproteinase 1 (TIMP-1), and galectin 3 (Gal-3) were studied before pacemaker implantation and six months later. RESULTS: Fifty-three patients were randomized to the HBP group and 39 patients to the RVP group. HBP failed in 10 patients, who crossed over to the RVP group. Patients with RVP had significantly lower LVEF compared to HBP patients after six months of pacing (-5% and -4% in as-treated and intention-to-treat analysis, respectively). Levels of TGF-ß1 after 6 months were lower in HBP than RVP patients (mean difference -6 ng/ml; P = 0.009) and preimplant Gal-3 and ST2-IL levels were higher in RVP patients, with a decline in LVEF ≥5% compared to those with a decline of <5% (mean difference 3 ng/ml and 8 ng/ml; P = 0.02 for both groups). CONCLUSION: In high-risk PICM patients, HBP was superior to RVP in providing more physiological ventricular function, as reflected by higher LVEF and lower levels of TGF-ß1. In RVP patients, LVEF declined more in those with higher baseline Gal-3 and ST2-IL levels than in those with lower levels.

A pilot randomised trial of catheter-directed thrombolysis or standard anticoagulation for patients with intermediate-high risk acute pulmonary embolism.

BACKGROUND: Intermediate-high risk acute pulmonary embolism (PE) remains associated with substantial mortality despite anticoagulation therapy. AIMS: The aim of this randomised pilot study was to compare catheter-directed thrombolysis to standard anticoagulation therapy. METHODS: Intermediate-high risk acute PE patients were admitted to a tertiary care centre (November 2019 to April 2021) and randomised in a 1:1 ratio to catheter-directed thrombolysis (CDT) or standard anticoagulation. Two catheters were used for the infusion of alteplase (1 mg/hr/catheter; total dose 20 mg) in the CDT group. The primary efficacy endpoint targeted improvement of right ventricular (RV) function, a decrease in pulmonary pressure, and a reduction of thrombus burden. RESULTS: Twenty-three patients were included (12 in the CDT group and 11 in the standard care group). The primary efficacy endpoint was achieved more frequently in the CDT group than in the standard care group (7 of 12 patients vs 1 of 11 patients, p=0.0004). An RV/left ventricular ratio reduction ≥25% (evident on computed tomography angiography) was achieved in 7 of 12 patients in the CDT group vs 2 of 11 patients in the standard care group (p=0.03). A systolic pulmonary artery pressure decrease of ≥30% or normotension at 24 hrs after randomisation was present in 10 of 12 patients in the CDT group vs 2 of 11 patients in the standard care group (p=0.001). There was no intracranial or life-threatening bleeding (type 5 or 3c bleeding, according to the Bleeding Academic Research Consortium classification). CONCLUSIONS: CDT for intermediate-high risk acute PE appears to be safe and effective. Further research is warranted to assess clinical endpoints.

Impact of His bundle pacing on right ventricular performance in patients undergoing permanent pacemaker implantation.

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.

Nonselective 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 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.