Clinical Trial: Quartet Lead With Defibrillator Multisite Algorithmic Cardiac Resynchronisation Therapy Optimisation

Study Status: Not yet recruiting
Recruit Status: Not yet recruiting
Study Type: Interventional

Official Title: Quartet Lead With Defibrillator Multisite Algorithmic Cardiac Resynchronisation Therapy Optimisation

Brief Summary:

Cardiac resynchronisation therapy (CRT) improves outcomes and symptoms in selected patients with heart failure. However, around one third of suitable patients do not demonstrate benefit following device implantation when assessed by echocardiography (heart scanning). This group has poorer outcomes.

Response rate can be enhanced by altering timing delays between the pacing leads, but some patients still fail to improve.

Quadripolar left ventricular leads are now widely used in CRT. The lead's four poles increase the number of conformations available to the programmer, allowing multiple vectors to be programmed simultaneously or sequentially. This allows programming to avoid, for example, a patch of scar and find an area that will respond better to pacing. This technique is known as multi-site pacing. CRT is often implanted along with a defibrillator lead in the right ventricle, known as CRT-D. The defibrillator lead offers further combinations for pacing.

Goal of Research To evaluate an algorithm for assessing different multi-site pacing combinations in optimisation of CRT

Outline The investigators will recruit 24 consecutive patients undergoing CRT-D implantation for conventional indications at our hospital. At baseline, patients will undergo echocardiography, exercise testing and assessments of functional ability and quality of life. The device will be implanted as standard. Optimisation will be performed with an algorithm using different vector combinations and assessing the heart's efficiency through echocardiography and invasive pressure monitoring. The pacemaker will be programmed with standard settings. After twelve weeks, the baseline investigations and optimisation algorithm will be repeated and the device programmed

Detailed Summary:

Study Design: This is an open-label, single centre, prospective, cohort study to assess the effect of algorithmic, echocardiography-guided optimisation of CRT-D following implantation of a left ventricular quadripolar lead.

Introduction and background:

There is now considerable evidence that cardiac resynchronisation therapy (CRT) improves outcomes and symptoms in patients with heart failure. However, around a third of patients do not demonstrate any haemodynamic or functional benefit following device implantation. Earlier studies have used a cut-off of 15% reduction in left ventricular end-systolic volume to define response to CRT.

Failure to respond to CRT is felt to be multifactorial. Issues include:

  • Anatomical limitations in terms of lead placement (the lead must be placed within a branch of the coronary sinus vein and therefore targeting to the site of maximum contraction delay can be difficult)
  • Presence of areas of scar tissue, which are resistant to being paced
  • Phrenic nerve stimulation with some pacing sites. The phrenic nerve runs close to the heart and may be stimulated by the pacemaker, with the effect that the patient's diaphragm is stimulated and they experience persistent hiccups.
  • High pacing thresholds, which means that increased power from the pacemaker must be used to create a successful pacing stimulus (capture) and that in some instances, capture may not be achieved. This can be due to scar or to poor contact with the heart tissue.

Previous work has demonstrated that response can be improved in some patients by opti
Sponsor: Cardiff and Vale University Health Board

Current Primary Outcome: Change in left ventricular end-systolic volume in patients undergoing algorithmic optimisation of CRT-D compared with usual device settings [ Time Frame: 24 weeks ]

End-systolic volume will be measured on echocardiography using Simpson's method. Where image quality precludes a full biplane assessment, single plane will be used with the apical 4-chamber view, or alternatively left ventricular end-systolic diameter will be used to calculate volume using the Teicholz method.


Original Primary Outcome: Same as current

Current Secondary Outcome:

  • Feasibility of algorithmic, echocardiography-guided CRT-D optimisation with quadripolar left ventricular leads in clinical practice [ Time Frame: 24 weeks ]
    To see whether our optimisation algorithm is acceptable to patients and easy to perform in clinical practice.
  • Correlation between invasive haemodynamic studies with non-invasive ultrasound-based methods in optimising CRT-D [ Time Frame: 24 weeks ]
    Attempt to establish a gold standard for optimisation of CRT devices by comparing invasive haemodynamic monitoring, echocardiographic parameters and cardiac output by ultrasound cardiac output monitoring (USCOM)
  • Change in left ventricular end diastolic pressure with algorithmic optimisation of CRT-D compared with usual device settings [ Time Frame: 24 weeks ]
    A measurement of left ventricular end-diastolic pressure will be made via invasive left ventricular monitoring after programming with usual settings and again after programming using algorithmic optimisation of the CRT-D device.
  • Feasibility of ultrasound cardiac output monitoring (USCOM) in optimisation of CRT devices in clinical practice [ Time Frame: At baseline and at 12 weeks ]
    Use of USCOM has been documented in optimisation of CRT, but not in such rapidly-changing algorithmic optimisation. We plan to assess whether it is feasible to use this in clinical practice as a replacement for a full echocardiogram.
  • Change in peak oxygen consumption with algorithmic CRT-D optimisation compared with usual device settings [ Time Frame: 24 weeks ]
    Assessment of peak oxygen consumption as measured by cardiopulmonary exercise testing after usual settings compared with settings after algorithmic optimisation.
  • Change in left ventricular ejection fraction with algorithmic CRT-D optimisation compared with usual device settings. [ Time Frame: 24 weeks ]
    Ejection fraction will be measured on echocardiography by Simpson's biplane method of discs. Where image quality precludes a full biplane assessment, single plane will be used with the apical 4-chamber view. Participants whose views are not sufficiently good quality for either of these measurements will be excluded from this outcome measure.
  • Change in left ventricular end-diastolic volume with algorithmic CRT-D optimisation compared with usual device settings. [ Time Frame: 24 weeks ]
    End-diastolic volume will be measured on echocardiography using Simpson's method. Where image quality precludes a full biplane assessment, single plane will be used with the apical 4-chamber view, or the Teicholz method will be used to estimate end-diastolic volume by measuring left ventricular end-diastolic diameter.
  • Change in left ventricular diastolic filling time with algorithmic CRT-D optimisation compared with usual device settings. [ Time Frame: 24 weeks ]
    Diastolic filling time will be measured on echocardiography using pulsed wave Doppler over the mitral inflow of the left ventricle.
  • Change in left ventricular outflow tract velocity time integral (LVOT VTI) with algorithmic CRT-D optimisation compared with usual device settings. [ Time Frame: 24 weeks ]
    LVOT VTI will be measured on echocardiography using pulsed wave Doppler within the left ventricular outflow tract, within 1cm of the aortic valve where a clear envelope is visible.
  • Change in longitudinal and global longitudinal strain (GLS) with algorithmic CRT-D optimisation compared with usual device settings. [ Time Frame: 24 weeks ]
    Longitudinal strain of the left ventricle will be measured on echocardiography using speckle tracking software
  • Change in radial strain with algorithmic CRT-D optimisation compared with usual device settings. [ Time Frame: 24 weeks ]
    Radial strain of the left ventricle will be measured on echocardiography using speckle tracking software
  • Change in distance walked on a 6-minute hall walk test with algorithmic CRT-D optimisation compared with usual device settings [ Time Frame: 24 weeks ]
    Patients will undergo a hall walk test at baseline, 12 weeks (with usual settings) and 24 weeks (following algorithmic optimisation) and the difference in distance walked will be analysed.
  • Change in New York Heart Association functional class with algorithmic CRT-D optimisation compared with usual device settings. [ Time Frame: 24 weeks ]
    Functional status will be assessed at baseline, after 12 weeks (with usual settings) and after 24 weeks (with optimised settings) and the change in class will be recorded.
  • Change in score in the Minnesota Living with Heart Failure Questionnaire (MLHFQ) between algorithmically optimised CRT-D and usual device

    Original Secondary Outcome: Same as current

    Information By: Cardiff and Vale University Health Board

    Dates:
    Date Received: December 7, 2016
    Date Started: January 2017
    Date Completion: May 2018
    Last Updated: December 15, 2016
    Last Verified: December 2016