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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
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

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
Cardiovascular Diseases
Heart Diseases processed this record on November 25, 2014