Using ultra‑high‑frequency ECG to distinguish true LBBB and guide whether left bundle branch or biventricular pacing is best
The Role of Ultra-high-frequency ECG in the Localization of Left Ventricular Conduction Disorders and Prediction of Response to Resynchronization Therapy
We will test whether ultra‑high‑frequency ECG can tell 'true' left bundle branch block from other intraventricular conduction delays and see if people with heart failure and a wide non‑RBBB QRS do better with left bundle branch pacing than with biventricular pacing.
Quick facts
| Phase | Not applicable |
|---|---|
| Study type | Interventional |
| Enrollment | 200 (estimated) |
| Ages | 18 Years and up |
| Sex | All |
| Sponsor | Faculty Hospital Kralovske Vinohrady Government |
| Locations | 1 site (Prague, Česká Republika) |
| Trial ID | NCT07057544 on ClinicalTrials.gov |
What this trial studies
This interventional project uses ultra‑high‑frequency ECG (UHF‑ECG) to map ventricular activation patterns and distinguish proximal ('true') LBBB from more distal intraventricular conduction delay (IVCD). Patients with heart failure, LVEF ≤40%, NYHA II–IV and non‑RBBB QRS ≥130 ms will undergo UHF‑ECG and either invasive EP confirmation or validated non‑invasive dyssynchrony assessment, then receive CRT by left bundle branch area pacing (LBBAP) or biventricular pacing (BVP). The study compares electrical dyssynchrony changes, echocardiographic remodeling, and clinical response between groups to see which pacing approach gives greater improvement in patients identified as true LBBB. Pilot data guiding the protocol suggest distinct activation patterns on UHF‑ECG and larger dyssynchrony in true LBBB patients.
Who should consider this trial
Good fit: Adults with ischemic or non‑ischemic cardiomyopathy, NYHA class II–IV, LVEF ≤40%, known coronary angiography, and a non‑RBBB QRS duration >130 ms are the intended candidates.
Not a fit: People with right bundle branch block, QRS <130 ms, reversible causes of heart failure, recent major cardiac events or surgery, severe valvular disease requiring intervention, or life expectancy under one year are unlikely to benefit from this protocol.
Why it matters
Potential benefit: If successful, this approach could help match each patient to the CRT method most likely to improve heart function and symptoms.
How similar studies have performed: Pilot studies and early reports indicate conduction‑system pacing can outperform biventricular pacing in some patients with true LBBB, but randomized evidence is still limited.
Eligibility criteria
Show full inclusion / exclusion criteria
Inclusion Criteria: * HF due to ischemic or non-ischemic cardiomyopathy * known coronary angiography * NYHA II-IV * LVEF ≤40% * non-RBBB QRSd lasting \>130 ms (by automated measurement) * proximal LBBB proved by an invasive EP study or non-invasive dyssynchrony assessment in case such a method is confirmed to be non-inferior to an invasive EP study during the project Exclusion Criteria: * Age ˂18 years * heart failure from reversible causes * Moderate to severe aortic stenosis * pregnancy * active myocarditis * hypertrophic cardiomyopathy * cardiac valve surgery in the last three months * myocardial infarction, PCI, or CABG in the last three months * severe valvular disease requiring intervention * severe atherosclerotic disease of the aorta and/or femoral arteries * life expectancy ˂1 year * known medical condition or contraindication causing potential complications for EP study
Where this trial is running
Prague, Česká Republika
- Faculty Hospital Kralovske Vinohrady — Prague, Česká Republika, Czechia (Recruiting)
Study contacts
- Study coordinator: Karol Curila, MD
- Email: karol.curila@fnkv.cz
- Phone: +420777869171
How to participate
- Review the eligibility criteria above with your treating physician.
- Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
- Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.