Conduction System Pacing Improved Cardiac Functions, Myocardial Work and Functional Capacity in Heart Failure with
Anna Zsófia Tóth1, László Nagy1, Csaba Jenei1
1Division of Cardiology, Department of Cardiology, Faculty of Medicine, University of Debrecen, Móricz Zsigmond krt. 22., H-4032 Debrecen, Hungary.
Insights
Conduction system pacing (CSP) significantly improved cardiac function and exercise capacity in heart failure patients with right bundle branch block (RBBB). These findings suggest CSP is a promising alternative to biventricular pacing for this patient group.
Area of Science:
- Cardiology
- Electrophysiology
- Heart Failure Management
Background:
- Conduction system pacing (CSP) is explored as an alternative to biventricular pacing (BVP) for heart failure with reduced ejection fraction (HFrEF) and bundle branch block.
- CSP may offer benefits in right bundle branch block (RBBB) patients, but its impact on cardiac mechanics and energetics requires further definition.
Purpose of the Study:
- To evaluate the echocardiographic and clinical outcomes of conduction system pacing (CSP) in patients with heart failure with reduced ejection fraction (HFrEF) and right bundle branch block (RBBB).
- To assess the effects of CSP on cardiac mechanics, energetics, functional status, and NT-proBNP levels in this specific patient cohort.
Main Methods:
- Conduction system pacing (CSP), including His bundle pacing or left bundle branch area pacing, was attempted as a primary strategy.
- Patients had RBBB, QRS duration ≥ 130 ms, LVEF < 35%, and NYHA II-IV symptoms despite optimized medical therapy.
- Echocardiographic parameters, functional status (NYHA class, 6-minute walk distance), and NT-proBNP levels were assessed at baseline and 6 months post-pacing.
Main Results:
- CSP reduced QRS duration (155.3 to 130 ms) and increased left ventricular ejection fraction (LVEF) (27% to 33%).
- Significant improvements were observed in left ventricular global longitudinal strain, peak strain dispersion, myocardial work index, constructive work, and work efficiency.
- Clinical outcomes improved, including NYHA class, 6-minute walk distance, and a decrease in NT-proBNP levels.
Conclusions:
- Conduction system pacing (CSP) demonstrated significant improvements in functional capacity and cardiac mechanics in HFrEF patients with RBBB.
- The study suggests CSP is a viable option that enhances myocardial work and efficiency, potentially improving outcomes in this population.
- Further validation through large-scale, multi-center randomized trials is warranted to confirm these promising findings.
Abstract:
Background/Objectives: Conduction system pacing (CSP) is a potential alternative to biventricular pacing (BVP) in heart failure with reduced ejection fraction (HFrEF) and left bundle branch block (LBBB) or non-LBBB. Available data also suggest that unlike BVP, CSP may improve clinical outcome in patients with right bundle branch block (RBBB), although its effects on cardiac mechanics and energetics are ill-defined. Herein, we report on echocardiographic and clinical outcomes of CSP in this patient cohort. Methods: CSP either with His bundle pacing or LBB area pacing was attempted as a primary strategy in patients with RBBB, QRS duration ≥ 130 ms, LVEF < 35% and NYHA II-IV symptoms after optimized medical therapy for 6 months. Data on functional status, NT-proBNP and echocardiographic parameters were collected at baseline and 6 months after CSP. Results: CSP performed in 16 patients reduced QRS duration from 155.3 ± 12.8 ms to 130 ± 16.5 ms (p < 0.001), increased LVEF from 27 ± 7% to 33 ± 9% (p = 0.01), improved LV global longitudinal strain from -7 ± 3% to -10 ± 4% (p = 0.004) and improved LV peak strain dispersion from 126 ± 28 ms to 96 ± 23 ms (p = 0.004). Global myocardial work index increased from 582 ± 277 mmHg% to 840 ± 306 mmHg% (p = 0.003), as did global constructive work (900 ± 374 mmHg% to 1203 ± 393 mmHg%; p = 0.006) and global work efficiency (from 71 ± 7% to 77 ± 8%; p = 0.004). NYHA class (12.5% with NYHA II, 87.5% with NYHA III before vs. 25% with NYHA I, 50% with NYHA II and 25% with NYHA III at 6 months; p = 0.002) and 6 min walk distance (from 354 ± 88 m to 411 ± 95 m; p = 0.003) improved, while NT-proBNP decreased (from 4093 ± 7215 ng/L to 2087 ± 2872 ng/L, p = 0.003). Conclusions: CSP improved functional capacity and echocardiographic parameters related to cardiac functions and myocardial work in HFrEF patients with RBBB. Nevertheless, these results await further confirmation by large-scale, multi-center randomized trials.
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