ABSTRACT
Background:
Right ventricular pacing (RVP)
therapy is the conventional approach for
atrioventricular block despite its propensity to cause electrical and mechanical dyssynchrony. This dyssynchrony increases the
risk of
atrial fibrillation and
heart failure, eventually leading to
left ventricular dysfunction. Left bundle branch pacing (LBBP) has recently emerged as a novel physiological pacing
method. This study utilizes conventional ultrasound
cardiography (UCG), two-dimensional speckle tracking imaging (2D-
STI), and
tissue Doppler imaging (TDI) to investigate the disparities in electrical and mechanical cardiac synchrony between LBBP and RVP
patients.
Methods:
The retrospective
analysis includes data from
patients who underwent LBBP (n=50) and RVP (n=50) in Zhangjiagang First People's
Hospital between January 2019 and June 2020, meeting the stipulated inclusion criteria. The study compares pacing
parameters, UCG
metrics, cardiac electrical and mechanical synchrony, pacing success rates, and
safety events both pre-operation and at 3, 6, 12, and 24 months post-operation.
Results:
Implantation success rates for both RVP and LBBP groups were 100%, with 92% and 100% pacing success rates, respectively [P = .001 RR (95% CI) 2.5 (1.5, 3.5)]. The LBBP group exhibited significant advantages over the RVP group throughout the follow-up period. LBBP
patients displayed shortened QRS duration, reduced pacing thresholds and
impedance, improved
sensory function, lower
serum NT-proBNP levels, and an increased proportion of NYHA class I
patients [P = .003 RR (95% CI) 1.6 (1.1, 2.3)]. Furthermore, left
ventricular ejection fraction increased significantly, while left ventricular diastolic and end-systolic diameters decreased in the LBBP group compared to the RVP group [P = .004 RR (95% CI) 1.7 (1.3, 2.2)]. The LBBP group also demonstrated shorter ventricular systolic synchrony
parameters, including Tls-Dif, PSD, Trs-SD, Tas-SD, Tas-post, Ts-SD, and Ts-DIf, compared to the RVP group [P = .005 RR (95% CI) 1.5 (1.2, 2.0)]. Notably, no
postoperative complications occurred in either group, such as
electrode displacement,
lead thrombus attachment, incision
bleeding, pocket
hemorrhage, or
infection. However, the readmission rates for
heart failure were 16% in the RVP group and 2% in the LBBP group.
Conclusion:
LBBP achieves physiological cardiac pacing, leading to significant improvements in
serum NT-proBNP levels and cardiac function and enhanced ventricular contraction synchrony. Utilizing UCG, 2D-
STI, and TDI for
quantitative evaluation of cardiac electrical and mechanical synchrony proves to be a valuable clinical approach.