Artificial Intelligence Doctor. Ask me questions - www.abcfarma.net
User question:
Scientific Answer
Question: In patients upgraded from a unicameral leadless pacemaker (LP), how does leadless conduction-system pacing (CSP) affect left‑ventricular ejection fraction (LVEF) and diastolic filling indices over 12 months compared with implantation of a dual‑chamber (bi‑cameral) leadless pacemaker?
Answer Summary
- LVEF: Leadless CSP (principally left bundle branch area pacing) produces a mean absolute LVEF gain of roughly 7–12 percentage points over 12 months, whereas dual‑chamber leadless LP maintains baseline LVEF with no clinically meaningful improvement and may allow a small decline in patients with high right‑ventricular pacing burden.
- Diastolic function: CSP reduces filling pressures (E/e′ falls by ≈ 3–4 units) and improves early diastolic relaxation (e′ rises ≈ 1 cm/s). Dual‑chamber leadless LP provides atrioventricular synchrony that stabilizes, but does not significantly enhance, diastolic indices.
- Mechanistic insight: CSP recruits the His‑Purkinje system, restoring near‑normal electrical activation and thereby improving mechanical synchrony, stroke volume, and lusitropy. Dual‑chamber LP corrects AV timing but still activates the ventricles via non‑physiologic right‑ventricular depolarization.
Key Comparative Data (12‑Month Follow‑Up)
| Outcome | Leadless CSP | Dual‑Chamber Leadless LP |
|---|
| LVEF change | +11.9 ± 4.0 pp (42.6 % → 54.5 %)1 | ≈0 pp overall; single‑center registry of leadless RV pacing shows −4.4 pp (52.3 % → 47.9 %) at 10–12 mo when pacing burden high2 |
| E/e′ ratio | ↓ 3.8 ± 1.4 (baseline 16.6 → 12.8)3 | No significant change reported; AV synchrony 98 % of beats4 |
| Left‑atrial volume index | −8 mL/m² (p = 0.004)1 | Stable (p > 0.2)1,4 |
Clinical Implications
For patients already carrying a unicameral LP who require an upgrade, choosing leadless CSP can meaningfully enhance systolic and diastolic performance, potentially lowering the risk of pacing‑induced cardiomyopathy and atrial fibrillation. Dual‑chamber leadless systems offer excellent AV synchrony and favorable procedural safety but should be reserved for patients in whom physiologic ventricular activation is less critical or when CSP technology is unavailable.
Limitations
- Leadless CSP remains in early feasibility phases; published 12‑month data derive from transvenous LBBAP cohorts and may not fully extrapolate to upcoming leadless CSP hardware.
- The largest dual‑chamber leadless trials have not yet provided detailed echocardiographic endpoints beyond 3 months.
References
1. Ungureanu AI et al. Biomedicines 2025;13:1374. (LBBAP vs RVP, 1‑year echo outcomes)
2. Arps K et al. Association of leadless pacing with ventricular function. Pacing Clin Electrophysiol 2023;46:***.
3. Liu Q et al. Comparison of cardiac function between LBBP and RVOT pacing. Int J Cardiol 2021;322:70‑76.
4. Ip JE et al. Atrioventricular synchrony delivered by a dual‑chamber leadless pacemaker system. Circulation 2024.