Comparing three types of specialist pacemakers to improve heart function and reduce rhythm problems in heart failure

Randomised investigation of physiological, conventional and optimised resynchronisation therapy in heart failure with prolonged QRS Duration

Status

Recruiting

Phases

Unknown

Study type

Interventional

Source

ISRCTN

Registry ID

ISRCTN60443207

Enrollment

Registered

2025-11-11

Start date

2025-11-12

Completion date

Unknown

Last updated

2026-01-05

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Heart failure with reduced ejection fraction and electrical dyssynchrony Circulatory System

Interventions

This is a 3-arm parallel (1:1:1) randomised study of cardiac resynchronisation therapy devices in patients with heart failure with reduced ejection fraction and electrical dyssynchrony. Randomisation

the current standard treatment - Conduction system pacing (CSP) - LOT-CRT (Left-bundle optimised CRT)

a combination of CSP and a coronary sinus left ventricular lead

Eligibility

Sex/Gender

All

Age

18 Years to 99 Years

Inclusion criteria

Inclusion criteria: Patients referred/scheduled for a CRT procedure (new implant or upgrade) who have: 1. Symptomatic heart failure (NYHA II-IV) 2. Reduced ejection fraction (LVEF=40%) 3. Prolonged QRS duration (=130ms) and left bundle branch block ECG morphology, or very prolonged QRS duration (>150ms) and non-left bundle branch block ECG 4. Optimal medical therapy for HF

Exclusion criteria

Exclusion criteria: 1. Unable to provide informed consent 2. <18 years old 3. Pregnant patients (with female patients of childbearing age requiring a negative urine BHCG)

Design outcomes

Primary

Measure	Time frame
1. Primary outcome: Daily ordinal symptom score with clinical over-rides measured using a daily ordinal scale with mobile application-based assessment of quality of life (using visual analogue scale), with clinical over-rides as detailed below, from randomisation to 6-months post-device implant: 1.1. Death 1.2. Intractable symptoms leading to trial exit/unblinding 1.3. Heart failure hospitalisation 1.4. Non-heart failure hospitalisation 1.5. Appropriate implantable cardioverter defibrillator therapy (anti-tachycardia pacing or shock, deemed appropriate as per the clinical care team interrogating the device) 1.6. Symptom score 2. Primary arrhythmia outcome: Ordinal arrhythmia scale using clinical endpoints as detailed below from randomisation to 6-months post-device implant: 2.1. Death 2.2. Appropriate implantable cardioverter defibrillator therapy (anti-tachycardia pacing or shock, deemed appropriate as per the clinical care team interrogating device) 2.3. Sustained ventricular arrhythmia (VA) (>30s of rhythm determined to be ventricular in origin by clinical team on device interrogation) 2.4. Sustained atrial arrhythmia 2.5. Non-sustained VA 2.6. >10% ventricular ectopy on 24h ECG 3. Primary contractility outcome: Ordinal contractility scale using clinical endpoints as detailed below from randomisation to 6-months post-device implant: 3.1. Death 3.2. Intractable symptoms leading to trial exclusion/unblinding 3.3. HF hospitalisation 3.4. Non-HF hospitalisation 3.5. LVEF	—

Measure

Time frame

1. Primary outcome: Daily ordinal symptom score with clinical over-rides measured using a daily ordinal scale with mobile application-based assessment of quality of life (using visual analogue scale), with clinical over-rides as detailed below, from randomisation to 6-months post-device implant: 1.1. Death 1.2. Intractable symptoms leading to trial exit/unblinding 1.3. Heart failure hospitalisation 1.4. Non-heart failure hospitalisation 1.5. Appropriate implantable cardioverter defibrillator therapy (anti-tachycardia pacing or shock, deemed appropriate as per the clinical care team interrogating the device) 1.6. Symptom score 2. Primary arrhythmia outcome: Ordinal arrhythmia scale using clinical endpoints as detailed below from randomisation to 6-months post-device implant: 2.1. Death 2.2. Appropriate implantable cardioverter defibrillator therapy (anti-tachycardia pacing or shock, deemed appropriate as per the clinical care team interrogating device) 2.3. Sustained ventricular arrhythmia (VA) (>30s of rhythm determined to be ventricular in origin by clinical team on device interrogation) 2.4. Sustained atrial arrhythmia 2.5. Non-sustained VA 2.6. >10% ventricular ectopy on 24h ECG 3. Primary contractility outcome: Ordinal contractility scale using clinical endpoints as detailed below from randomisation to 6-months post-device implant: 3.1. Death 3.2. Intractable symptoms leading to trial exclusion/unblinding 3.3. HF hospitalisation 3.4. Non-HF hospitalisation 3.5. LVEF

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Secondary

Measure	Time frame
1. Death from any cause will be measured using an appraisal of electronic health records and contacting the primary care providers if that is not available, by occurrence of death, from randomisation up to 36 months or until death, whichever occurs first. 2. Intractable symptoms leading to trial exit/unblinding will be measured using an appraisal of electronic health records and contacting the primary care providers if that is not available, by occurrence of intractable symptoms, from randomisation up to 36 months or until trial exit/unblinding, whichever occurs first. 3. Heart failure hospitalisation will be measured using an appraisal of electronic health records and contacting the primary care providers if that is not available, by adjudicated unplanned heart failure acute care (hospital admissions or ambulatory diuretic therapy), from randomisation up to 36 months. 4. Non-heart failure hospitalisation will be measured using an appraisal of electronic health records and contacting the primary care providers if that is not available, by adjudicated unplanned non-heart failure acute care (hospital admissions or ambulatory emergency clinic), from randomisation up to 36 months. 5. Appropriate implantable cardioverter defibrillator device therapy will be measured using an appraisal of electronic health records and contacting the primary care providers if that is not available, by adjudicated anti-tachycardia pacing or shock for ventricular arrhythmia, from randomisation up to 36 months. 6. Daily heart failure symptom score, measured by mobile app-based daily ordinal score (0–600 scale), from randomisation up to 36 months. 7. Sustained ventricular arrhythmia, measured by adjudicated device interrogation showing arrhythmia >30 seconds, from randomisation up to 36 months. 8. Sustained atrial arrhythmia, measured by adjudicated device interrogation showing arrhythmia >30 seconds, from randomisation up to 36 months. 9. Non-sustained ventricular arrhythmia, measure	—

Measure

Time frame

1. Death from any cause will be measured using an appraisal of electronic health records and contacting the primary care providers if that is not available, by occurrence of death, from randomisation up to 36 months or until death, whichever occurs first. 2. Intractable symptoms leading to trial exit/unblinding will be measured using an appraisal of electronic health records and contacting the primary care providers if that is not available, by occurrence of intractable symptoms, from randomisation up to 36 months or until trial exit/unblinding, whichever occurs first. 3. Heart failure hospitalisation will be measured using an appraisal of electronic health records and contacting the primary care providers if that is not available, by adjudicated unplanned heart failure acute care (hospital admissions or ambulatory diuretic therapy), from randomisation up to 36 months. 4. Non-heart failure hospitalisation will be measured using an appraisal of electronic health records and contacting the primary care providers if that is not available, by adjudicated unplanned non-heart failure acute care (hospital admissions or ambulatory emergency clinic), from randomisation up to 36 months. 5. Appropriate implantable cardioverter defibrillator device therapy will be measured using an appraisal of electronic health records and contacting the primary care providers if that is not available, by adjudicated anti-tachycardia pacing or shock for ventricular arrhythmia, from randomisation up to 36 months. 6. Daily heart failure symptom score, measured by mobile app-based daily ordinal score (0–600 scale), from randomisation up to 36 months. 7. Sustained ventricular arrhythmia, measured by adjudicated device interrogation showing arrhythmia >30 seconds, from randomisation up to 36 months. 8. Sustained atrial arrhythmia, measured by adjudicated device interrogation showing arrhythmia >30 seconds, from randomisation up to 36 months. 9. Non-sustained ventricular arrhythmia, measure

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Countries

England, United Kingdom

Contacts

Public ContactJack Samways

j.samways@nhs.net+44 020 3313 3000

Outcome results

None listed

Source: ISRCTN (via WHO ICTRP) · Data processed: Feb 4, 2026