The Effect of CRT on the Frank Starling Mechanism

Sponsor
Guy's and St Thomas' NHS Foundation Trust (Other)
Overall Status
Not yet recruiting
CT.gov ID
NCT05993585
Collaborator
King's College London (Other)
40
1
2
21.9
1.8

Study Details

Study Description

Brief Summary

The investigators are examining a scientific principle called the Frank Starling Mechanism and how it relates to Cardiac Resynchronisation Therapy (CRT), a form of pacemaker therapy used in the treatment of heart failure.

The Frank Starling Mechanism is an established biological principle. The law states that the stroke volume of the heart increases in response to an increase in the volume of blood in the ventricles, before contraction, when all other factors remain constant. In other words, the law states that the more blood enters the heart, the more blood is pumped out of the heart with any given beat.

There is some evidence that in some patients with chronic heart conditions, the Frank Starling Mechanism is LESS EFFECTIVE, meaning that the heart is less able to cope with a reduction in heart pumping function over time. There is also evidence that treatment with CRT may IMPROVE the Frank Starling Mechanism - evidence for this has been shown in dog and mice hearts, however, has never been shown in humans.

The investigators aim to conduct a study where subjects undergo an ultrasound scan of the heart (echocardiogram) whilst the participants pacemaker settings are temporarily changed. This allows the investigators to measure the pumping function of the heart as more blood enters the heart. The investigators will perform this test on 20 participants before and after CRT, as well as 20 participants who have pacemakers, but no heart failure. This study aims to test 3 hypotheses.

  1. In participants with pacemakers, a REDUCED Frank Starling Mechanism predicts which participants go on to develop heart failure.

  2. Treatment with CRT IMPROVES the Frank Starling Mechanism in participants with pacemakers and heart failure.

  3. The degree of improvement of the Frank Starling Mechanism after treatment with CRT predicts which participants will respond to this treatment.

Condition or Disease Intervention/Treatment Phase
  • Other: Test Of The Frank Starling Mechanism - Adjustment Of Av Delay And Measurement Of Pre-load -Control
  • Other: Other: Test Of The Frank Starling Mechanism - Adjustment Of Av Delay And Measurement Of Pre-load -CRT
N/A

Detailed Description

The primary research investigation in this study is a non-invasive test of the Frank Starling mechanism, which involves performing a transthoracic echocardiogram (ultrasound scan of the heart) whilst temporarily changing pacemaker settings to mimic conditions such as faster heart rates or increased blood flow to the heart. Measurements taken from the echocardiogram during these changes in pacemaker settings will be used to determine the effectiveness of the heart's Starling Mechanism. This test will last between 20-40 minutes. No special preparation is needed and participants will be able to go home immediately afterwards. Pacemaker settings will be returned to normal once the test is completed.

Study Design

Study Type:
Interventional
Anticipated Enrollment :
40 participants
Allocation:
Non-Randomized
Intervention Model:
Parallel Assignment
Intervention Model Description:
Single centre trial - observational cohort studySingle centre trial - observational cohort study
Masking:
None (Open Label)
Primary Purpose:
Basic Science
Official Title:
The Effects of Cardiac Resynchronisation Therapy on the Frank Starling Mechanism in Patients With Heart Failure
Anticipated Study Start Date :
Aug 4, 2023
Anticipated Primary Completion Date :
Jun 2, 2025
Anticipated Study Completion Date :
Jun 2, 2025

Arms and Interventions

Arm Intervention/Treatment
Experimental: CRT Group

CRT group: We will include patients with symptomatic heart failure (LV ejection fraction <35% on TTE, NYHA II-IV) and an RV pacing percentage of >40%, thus meeting ESC Criteria for CRT upgrade.

Other: Test Of The Frank Starling Mechanism - Adjustment Of Av Delay And Measurement Of Pre-load -Control
(Control Group): One test of the Starling mechanism Visit 1: Sign consent form, doctor assessment, electrocardiogram (ECG), Starling Test. If patients are in this category, this will be their only research visit

Active Comparator: Control Group

Control group: patients with an existing dual chamber pacemaker and with preserved ejection fraction

Other: Other: Test Of The Frank Starling Mechanism - Adjustment Of Av Delay And Measurement Of Pre-load -CRT
(CRT Group): Two tests of the Starling mechanisms Visit 1: Sign consent form, assessment by doctor, electrocardiogram (ECG), Test of the Starling mechanism Visit 2: CRT upgrade procedure - your Cardiologist will explain this procedure to you. Visit 3: CRT pacing check at 6 weeks post-procedure Visit 4: Assessment by doctor, ECG, Echocardiogram, Test of the Starling mechanism at 6 months post-procedure.

Outcome Measures

Primary Outcome Measures

  1. Difference in starling mechanism [Prior to pacing test (starling mechanism test) and after six months]

    1. Difference in maximum change in stroke volume (SV) in millilitres with AV delay modification "Starling mechanics" pre-CRT versus post-CRT (difference between lowest and highest SV).

Secondary Outcome Measures

  1. Left ventricular end-systolic volume (ml) [Prior to pacing test (starling mechanism test) and after six months]

    Difference in left ventricular end-systolic volume in millimetres recorded on echocardiogram

  2. Left ventricular ejection fraction (%) [Prior to pacing test (starling mechanism test) and after six months]

    Difference in Left ventricular ejection fraction in percent measured on echocardiogram

  3. Quality of life with heart failure symptoms [Prior to pacing test (starling mechanism test) and after six months]

    Quality of life in heart failure assessed by Minnesota Living with Heart Failure Questionnaire

  4. Heart failure symptoms [Prior to pacing test (starling mechanism test) and after six months]

    New York Heart Association ( NYHA) class - breathlessness on different levels of exercise - from walking on the flat (NYHA 2) up to limited by breathlessness on little movement (NYHA 4)

  5. Packer's clinical composite score [Prior to pacing test (starling mechanism test) and at six months]

    Difference in patient outcome measured by the clinical composite score - the score ranges from improved to unchanged or worsened

  6. Difference in baseline Starling mechanics between CRT group and control group [Prior to pacing test (starling mechanism test) and at six months]

    Difference in stroke volume in millilitres during the pacing test (starling mechanism test) between the CRT and control group

Eligibility Criteria

Criteria

Ages Eligible for Study:
18 Years and Older
Sexes Eligible for Study:
All
Accepts Healthy Volunteers:
No
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

Contacts and Locations

Locations

Site City State Country Postal Code
1 Guy's and St Thomas' NHS Trust London United Kingdom SE1 7EH

Sponsors and Collaborators

  • Guy's and St Thomas' NHS Foundation Trust
  • King's College London

Investigators

  • Principal Investigator: Christopher Aldo Rinaldi/Professor, MD, FHRS, Guy's and St Thomas' NHS Trust
  • Principal Investigator: Steven Niederer/Professor, PhD, King's College London

Study Documents (Full-Text)

None provided.

More Information

Publications

Responsible Party:
Guy's and St Thomas' NHS Foundation Trust
ClinicalTrials.gov Identifier:
NCT05993585
Other Study ID Numbers:
  • 318500
First Posted:
Aug 15, 2023
Last Update Posted:
Aug 15, 2023
Last Verified:
Jul 1, 2023
Individual Participant Data (IPD) Sharing Statement:
Yes
Plan to Share IPD:
Yes
Studies a U.S. FDA-regulated Drug Product:
No
Studies a U.S. FDA-regulated Device Product:
No
Keywords provided by Guy's and St Thomas' NHS Foundation Trust
Additional relevant MeSH terms:

Study Results

No Results Posted as of Aug 15, 2023