RethinQ Study - Evaluating Pacing in Heart Failure Patients

This study has been completed.
Information provided by:
St. Jude Medical Identifier:
First received: August 18, 2005
Last updated: May 5, 2008
Last verified: May 2008

Patients with heart failure have a pumping action of the ventricles in which one ventricle contracts before the other ventricle. This uncoordinated (unsynchronized) pumping is due to a delay in the stimulation of the left ventricle because of its increased size. Pacing both the right and the left side of the heart (or cardiac resynchronization therapy [CRT]) has been proven to be effective in the treatment of heart failure (HF). Current market-approved devices combine both pacing (CRT) and shocking (implantable cardioverter defibrillator [ICD]) therapy for patients who have severe heart failure and are at risk for developing life-threatening heart rhythms. These devices provide an electrical pacing stimulus to both ventricles and may help the heart contract in a more coordinated way and improve heart failure symptoms.

The investigational portion of this trial involves the implantation of a market-approved CRT implantable cardioverter defibrillator (CRT-D) system in patients who do not meet the current criteria for a CRT implant. In order to receive a CRT-D implant today, patients must have heart failure symptoms, have a weakened heart muscle, and have uncoordinated pumping of the heart. To demonstrate this uncoordinated pumping of the heart, a test (electrocardiogram [ECG]) is done. It is believed that by using a different test (echocardiogram) to measure whether this uncoordinated pumping is present, more patients will be identified that will benefit from CRT-D therapy. This study will look at whether patients identified by using this echocardiogram test show a benefit from having this CRT-D therapy.

Condition Intervention Phase
Heart Failure
Device: Cardiac Resynchronization Therapy
Phase 3

Study Type: Interventional
Study Design: Allocation: Randomized
Endpoint Classification: Safety/Efficacy Study
Intervention Model: Parallel Assignment
Masking: Double-Blind
Primary Purpose: Treatment
Official Title: Resynchronization Therapy in Normal QRS (RethinQ) Clinical Investigation

Resource links provided by NLM:

Further study details as provided by St. Jude Medical:

Primary Outcome Measures:
  • Cardiac resynchronization therapy (CRT) effectiveness will be evaluated in terms of exercise capacity (peak VO2), as measured by cardiopulmonary exercise testing [ Time Frame: 6 months ]
  • Safety will be evaluated in terms of survival from CRT-D system-related complications. [ Time Frame: 6 months ]

Secondary Outcome Measures:
  • Quality of Life Questionnaire [ Time Frame: 6 months ]
  • New York Heart Association (NYHA) Classification [ Time Frame: 6 months ]

Enrollment: 250
Study Start Date: July 2005
Study Completion Date: July 2007
Primary Completion Date: July 2007 (Final data collection date for primary outcome measure)
  Show Detailed Description


Ages Eligible for Study:   18 Years and older
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  • Have an approved indication for implantation of an ICD.
  • Have advanced HF with a New York Heart Association (NYHA) Classification of III, despite receiving optimal pharmacological therapy.
  • Have a stable heart failure medical regimen.
  • Have a left ventricular ejection fraction (LVEF) <= 35%.
  • Have evidence of mechanical dyssynchrony as measured by echocardiography using tissue Doppler imaging or M-mode.
  • Have a QRS duration < 130 ms (present in all ECG leads).
  • Have the ability to complete exercise stress testing and 6-minute hall walk test, with the only limiting factors being related to cardiac fitness.
  • Have the ability to independently comprehend and complete a quality of life questionnaire.
  • Have the ability to provide informed consent for study participation and be willing and able to comply with the prescribed follow-up tests and schedule of evaluations.

Exclusion Criteria:

  • Have a standard bradycardic indication for pacing.
  • Have been previously treated with CRT.
  • Have continuous atrial fibrillation [AF] (continuous is defined as AF lasting > 1 month) within 1 year prior to enrollment or have undergone cardioversion for AF in the past month.
  • Have the ability to walk > 450 meters during the 6-minute walk test.
  • Have a NYHA Classification of I, II or IV.
  • Have symptomatic chronic obstructive pulmonary disease (COPD) as it relates to exercise ability.
  • Have a classification of Status 1 for cardiac transplantation or consideration for transplantation over the next 6 months.
  • Have had a recent myocardial infarction, unstable angina or cardiac revascularization (percutaneous transluminal coronary angioplasty [PTCA] or coronary artery bypass graft [CABG]) within 40 days of enrollment.
  • Have had a recent cerebrovascular accident (CVA) or transient ischemic attack (TIA) within 3 months of enrollment.
  • Have severe musculoskeletal disorder(s).
  • Pregnant or planning for pregnancy in the next 6 months.
  • Currently participating in, or have participated in any clinical investigation within the last 30 days (the only exception being that of a registry trial).
  • Have a life expectancy of less than 6 months.
  • Less than 18 years of age.
  Contacts and Locations
Please refer to this study by its identifier: NCT00132977

  Show 34 Study Locations
Sponsors and Collaborators
St. Jude Medical
Study Chair: John Beshai, MD University of Chicago
  More Information

Responsible Party: Director, Clinical Affairs, St. Jude Medical, CRMD Identifier: NCT00132977     History of Changes
Other Study ID Numbers: G050084
Study First Received: August 18, 2005
Last Updated: May 5, 2008
Health Authority: United States: Food and Drug Administration

Keywords provided by St. Jude Medical:
Cardiac Resynchronization Therapy
Heart Failure
Mechanical Dyssynchrony

Additional relevant MeSH terms:
Heart Failure
Heart Diseases
Cardiovascular Diseases processed this record on April 23, 2014