Lung Impedance Monitoring In Treatment of Chronic Heart Failure (LIMIT-CHF)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT01320007
Recruitment Status : Completed
First Posted : March 22, 2011
Last Update Posted : July 9, 2015
Information provided by (Responsible Party):
Barts & The London NHS Trust

Brief Summary:

Heart failure is a major clinical problem that is increasing in magnitude and the cost of management of heart failure is escalating. A significant part of this cost is related to unplanned acute presentation to emergency departments and hospitalisation with worsening shortness of breath due to increased fluid content in the lungs.

Many heart failure patients are already fitted with defibrillators to protect them from the risk of fast heart rhythms and sudden death and are followed up in both the heart failure clinics and defibrillator clinics. Recently some of the defibrillators fitted have been equipped with an extra function that can detect and warn of changes in the fluid content of the lungs very early even before the patient starts to complain of any shortness of breath and before any signs of fluid overload are seen clinically. However, it is not known how to deal with these warnings if they occur very early and it is not known whether a medical intervention at his stage is beneficial to prevent progression and eventual hospital admission. In the majority of cases, early warnings of this kind are ignored or this function is disabled at implantation of the device.

The current study will involve patients who have already been fitted with a device with the above capability. The investigators will use the new function to guide management of these patients and compare their outcome with similar patients who are fitted with devices without it. The investigators will attempt to manage early warnings by a predetermined increase in medications in a group of patients and compare their clinical course to a similar group in whom no action is taken.

Condition or disease Intervention/treatment Phase
Heart Failure Drug: Preset increase in frusemide dose Other: No intervention Not Applicable

Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 80 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: Lung Impedance Monitoring In Treatment of Chronic Heart Failure
Study Start Date : September 2010
Actual Primary Completion Date : October 2014
Actual Study Completion Date : December 2014

Resource links provided by the National Library of Medicine

MedlinePlus related topics: Heart Failure
U.S. FDA Resources

Arm Intervention/treatment
Experimental: Group 1: Optivol Group Drug: Preset increase in frusemide dose

All patients in Group 1 will have the Optivol function and alerts switched on. Optivol levels will be downloaded monthly via the Medtronic Carelink Network (for those patients who have it) or during pacemaker follow up appointments.

If the Optivol alarm goes off, all patients will be requested to contact a member of the research team by phone and those with rising Optivol (irrespective of the presence or absence of heart failure symptoms) will be requested to increase the dose of diuretic that they are on by 50% for 1 week then revert to their usual dose after 7 days. A routine renal function check will be performed at the end of the week.

Active Comparator: Group 2: Optivol alarm muted Other: No intervention
The Optivol data for these patients will be downloaded periodically (at each scheduled device check) and recorded but will not be available at follow up in the heart failure clinic.. These patients will act as controls for group 1 patients. They will undergo baseline investigations and then will undergo routine heart failure treatment and follow-up in the heart failure clinic. These will include a routine clinical evaluation, body weight and blood analysis as per the heart failure clinic protocol. Medications will be reviewed and changed according to clinical needs.

Primary Outcome Measures :
  1. The number of unplanned hospitalisations or acute unscheduled care in the emergency department or heart failure clinic [ Time Frame: 1 year ]
    The primary study end-point will be a comparison between groups 1 and 2 regarding the ratio of the number of readmissions for heart failure to the total number of patients in each group of the two main groups over the course of the study (i.e. number of readmissions per patient)

Secondary Outcome Measures :
  1. NYHA functional Class improvement of at least 1 grade [ Time Frame: 1 year ]
    The proportion of patients achieving at least 1 grade improvement in New York Heart Association functional class in each group

  2. Minnesota Quality of Life Score improvement in each group [ Time Frame: 1 Year ]
    A comparison between the 2 study groups regarding the magnitude of improvement in the Minnesota Living with Heart Failure (questionnaire) score at 1 year compared to baseline

  3. Change in the 6 minute walk test(6MWT)distance in metres [ Time Frame: 1 year ]
    A comparison between the change in the 6MWT distance covered (at 1 year compared to baseline) in each of the 2 study groups

  4. Change in the level of BNP in serum (pg/ml) [ Time Frame: 1 year ]
    A comparison between between the 2 study groups regarding the change in level of BNP at 1 year compared to baseline

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years and older   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Previously fitted with an ICD or a CRT-D device for primary or secondary prevention (for at least 34 days) with a Medtronic Optivol capable Device
  • Previous hospital admission for decompensated heart failure
  • Left ventricular systolic dysfunction (EF <50%)
  • Currently compensated heart failure with a functional class of III or better
  • All patients will be on optimal medical treatment including a beta blocker, an ACEI (or ARB) and spironolactone unless contraindicated or not tolerated

Exclusion Criteria:

  • Decompensated patients who have NYHA class IV or clinical signs of lung congestion at time of evaluation (these patients may be included later if/when their NYHA class improves)
  • Patients with a high Optivol fluid index at time of evaluation (these patients may be included later when the Optivol fluid index comes down)
  • Patients with advanced renal failure ± dialysis (Chronic Kidney Disease class 4 or 5 with an estimated GFR of <30 ml/min)

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT01320007

United Kingdom
St Bartholomew's Hospital
London, United Kingdom, EC1A 7BE
Sponsors and Collaborators
Barts & The London NHS Trust
Principal Investigator: Richard J Schilling, Md FRCP Barts and the London NHS Trust, Queen Mary University of London

Publications automatically indexed to this study by Identifier (NCT Number):
Responsible Party: Barts & The London NHS Trust Identifier: NCT01320007     History of Changes
Other Study ID Numbers: BLT006957
First Posted: March 22, 2011    Key Record Dates
Last Update Posted: July 9, 2015
Last Verified: February 2015

Additional relevant MeSH terms:
Heart Failure
Heart Diseases
Cardiovascular Diseases