Examining how Cardiac Resynchronisation Therapy affects heart function

The Effects of Cardiac Resynchronisation Therapy on the Frank Starling Mechanism in Patients With Heart Failure

Not applicable Interventional Guy's and St Thomas' NHS Foundation Trust · NCT05993585

This study is testing how a heart treatment called Cardiac Resynchronisation Therapy affects heart function in people with severe heart failure by looking at how their hearts respond to different settings on their pacemakers.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment40 (estimated)
Ages18 Years and up
SexAll
SponsorGuy's and St Thomas' NHS Foundation Trust Academic / other
Locations1 site (London)
Trial IDNCT05993585 on ClinicalTrials.gov

What this trial studies

This study investigates the Frank Starling Mechanism, which describes how the heart's stroke volume increases with more blood in the ventricles, in relation to Cardiac Resynchronisation Therapy (CRT) for heart failure. Participants will undergo a non-invasive echocardiogram while their pacemaker settings are adjusted to simulate different heart conditions. The goal is to assess how effectively the heart responds to these changes, particularly in patients with severe left ventricular impairment. The test lasts 20-40 minutes, and participants can return home immediately afterward.

Who should consider this trial

Good fit: Ideal candidates include patients with existing dual chamber pacemakers and severe left ventricular systolic impairment who are experiencing heart failure symptoms.

Not a fit: Patients with a history of CRT treatment or those with persistent atrial fibrillation may not benefit from this study.

Why it matters

Potential benefit: If successful, this study could enhance the understanding of heart function and improve treatment strategies for patients with heart failure.

How similar studies have performed: While there is evidence from animal studies suggesting CRT may improve the Frank Starling Mechanism, this specific investigation in humans is novel.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* • Ability to provide informed consent to participate and willing to comply with the clinical investigation plan and follow-up schedule.

  * Existing dual chamber pacemaker or ICD including atrial lead and RV lead.
  * RV pacing percentage \>40%.
  * CRT group - Severe left ventricular systolic impairment (LVEF≤35%). Clinical symptoms of heart failure despite optimum medical therapy (NYHA class II-IV).
  * Control group - LVEF \>50%.

Exclusion Criteria:

* • Previous treated with CRT (existing LV lead/His-Bundle lead/Left Bundle Branch Area lead).

  * Persistent atrial fibrillation
  * Female participants who are pregnant, lactating or planning pregnancy during the course of the study.
  * Participation in other studies with active treatment / investigational arm

Where this trial is running

London

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions PacemakerHeartfailureFrank Starling MechanismCRT
Last reviewed 2026-06-09 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.