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NCT Number: NCT07084467

A Study Testing a New Heart Scan Method to Improve Pacemaker Treatment for Heart Failure

Cardiac resynchronization therapy (CRT) is a device treatment for patients with heart failure which cannot be managed by medications alone. CRT can help the heart contract more efficiently and improve the pumping function. However, many patients do not benefit from this treatment. Therefore, a better selection tool will help us to determine the most suitable patients to receive this treatment. A new measure of pumping function of the heart called: first-phase ejection fraction or EF1 has been shown a good tool to select suitable patients for CRT. EF1 is a sensitive measurement of heart function and can be easily measured by echocardiography (an ultrasound heart scan).

The purpose of this study is to examine whether this new measurement (EF1) can predict outcomes and response to CRT treatment.

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Key information

Conditions

Cardiac Resynchronisation Therapy (CRT) Cardiovascular Diseases Heart Diseases Heart Failure

Age range

18 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Guy's and St. Thomas' NHS Foundation Trust

London, United Kingdom

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Age 18 years or older
  • On optimal medical therapy for heart failure
  • Meets standard guideline criteria for CRT (including conduction system pacing), specifically:
  • NYHA class II to IV
  • Left ventricular ejection fraction (EF) ≤ 35%
  • QRS duration > 130 ms

Exclusion criteria

  • Co-morbidities likely to reduce life expectancy to less than 6 months
  • Major cardiovascular event within the past 6 weeks
  • More than mild aortic stenosis
  • Receiving continuous or intermittent infusion therapy for heart failure
  • Poor ultrasound acoustic window preventing adequate imaging
  • Unable to give informed consent
  • Currently participating in another interventional study

Treatment and study plan

EF1 guided CRT optimisation

Other

In the EF1-guided optimisation group, the settings of the CRT device are adjusted to maximise early heart pumping efficiency, measured by a parameter called first-phase ejection fraction (EF1). Depending on the patient's heart rhythm, either the timing between heart chambers (AV or VV delay) is adjusted in small steps. The device setting that gives the best EF1 reading is chosen to help improve the heart's response to CRT.

Standard of Care (SOC)

Other

This group will receive standard of care for their health condition and CRT management.

Primary outcomes

  1. Volumetric response of left ventricle

    Time frame: 6 months post CRT implantation or 6 months post CRT optimisation

    This will be defined as a reduction in left ventricular end-systolic volume by more than 15% at following CRT implantation comparing to before CRT implantation on echocardiogram.

Secondary outcomes

  1. Hospitalization for heart failure or all-cause death

    Time frame: From enrollment to 36 months post CRT implantation

    This composite endpoint will be collected over the entire duration of follow-up in the trial when the last patient randomized has reached 36 months of follow-up post CRT implantation.

Study contacts

Contact information is provided by the study sponsor or research team.

Haotian Gu, PhD

CONTACT

[email protected]

+44(0)2071884700

Phil Chowienczyk, PhD

CONTACT

[email protected]

Sponsors and collaborators

Lead sponsor

King's College London

Other

Collaborators

  • Barts & The London NHS Trust
  • Guy's and St Thomas' NHS Foundation Trust
  • King's College Hospital NHS Trust
  • The Leeds Teaching Hospitals NHS Trust

Registry information

Official study title

Evaluation of First-Phase Ejection Fraction to Guide Cardiac Resynchronization Therapy - A Randomised Controlled Trial

Acronym: EFFECT-CRT

Important dates

Study start
2025
Primary completion
2030
Study completion
2030
First posted
Jul 24, 2025
Registry last updated
Aug 3, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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