LVSP and LBBP Result in Similar or Improved LV Synchrony and Hemodynamics Compared to BVP.

Background: The effect of left ventricular septal myocardial pacing (LVSP) and left bundle branch pacing (LBBP) on ventricular synchrony and left ventricular (LV) hemodynamic status is poorly understood.
Objectives: The aim of this study was to investigate the impact of LVSP and LBBP vs biventricular pacing (BVP) on ventricular electrical synchrony and hemodynamic status in cardiac resynchronization therapy patients.
Methods: In cardiac resynchronization therapy candidates with LV conduction disease, ventricular synchrony was assessed by measuring QRS duration (QRSd) and using ultra-high-frequency electrocardiography. LV electrical dyssynchrony was assessed as the difference between the first activation in leads V ₁ to V ₈ to the last from leads V ₄ to V ₈ . LV hemodynamic status was estimated using invasive systolic blood pressure measurement during multiple transitions between LBBP, LVSP, and BVP.
Results: A total of 35 patients with a mean LV ejection fraction of 29% and a mean QRSd of 168 ± 24 ms were included. Thirteen had ischemic cardiomyopathy. QRSd during BVP, LVSP, and LBBP was the same, but LBBP provided shorter LV electrical dyssynchrony than BVP (-10 ms; 95% CI: -16 to -4 ms; P = 0.001); the difference between LVSP and BVP was not significant (-5 ms; 95% CI: -12 to 1 ms; P = 0.10). LBBP was associated with higher systolic blood pressure than BVP (4%; 95% CI: 2%-5%; P < 0.001), whereas LVSP was not (1%; 95% CI: 0%-2%; P = 0.10). Hemodynamic differences during LBBP and LVSP vs BVP were more pronounced in nonischemic than ischemic patients.
Conclusions: Ultra-high-frequency electrocardiography allowed the documentation of differences in LV synchrony between LBBP, LVSP, and BVP, which were not observed by measuring QRSd. LVSP provided the same LV synchrony and hemodynamic status as BVP, while LBBP was better than BVP in both.
Competing Interests: Funding Support and Author Disclosures This work was supported by the Charles University Research Program Cooperation-Cardiovascular Science (Dr Curila), the Ministry of Health of the Czech Republic (grant NU21-02-00584 to Dr Curila), and National Institute for Metabolic and Cardiovascular Research “CarDia” (Programme EXCELES, ID Project No. LX22NPO5104), funded by the European Union – Next Generation EU (Dr Curila). Authors from the Cardiocenter, Third Faculty of Medicine, Charles University and University Hospital Kralovske Vinohrady, from Institute of Scientific Instruments, the Czech Academy of Sciences, have filed U.S. patent 11,517,243 B2, “Method of Electrocardiographic Signal Processing and Apparatus for Performing the Method” and are shareholders of VDI Technologies. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
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