Predicting Response to Cardiac Resynchronization Therapy in Heart Failure

Completed

Conditions studied: Heart Failure, Left Ventricular Dysfunction

In brief

This study will explore which characteristics of patients with heart failure will likely predict improvement after cardiac resynchronization (CRT), implantation of a pacemaker to improve heart function. In spite of major medical advances, about 30% to 40% of patients with heart failure do not respond to CRT, and the reasons are not well understood. This study will involve magnetic resonance imaging (MRI), electrocardiogram (ECG), and echocardiography techniques to let researchers examine what may influence response to CRT. Patients ages 18 and older with a left ventricular disorder and who are not pregnant or breastfeeding may be eligible for this study. Initial evaluation will take 5 to 6 hours. A blood sample of about 2 tablespoons will be collected, and several procedures will be performed. MRI uses a strong magnetic field and radio waves to obtain images of body organs and tissues. For that procedure, patients will lie on a table that slides into the enclosed tunnel of the scanner and be asked to lie still. They will be in the scanner for 30 to 90 minutes. As the scanner takes pictures, patients will hear knocking sounds, and they may be asked to hold their breath intermittently for 5 to 20 seconds. During part of the scan, a drug called gadolinium will be given intravenously (IV), to make the heart easier to see. Patients will be able to communicate with the MRI staff at all times during the scan. At any time, patients may ask to be moved out of the machine. Patients having metal in their body that interferes with the MRI scanner should not have this test. During the procedure, an ECG machine will monitor the heart, through wires connected to pads on the skin. Patients will have an echocardiogram, in which sound waves look at the heart. A small handheld probe will touch the chest and abdomen, and an IV tube may be inserted to inject a contrast drug to improve the quality of heart images. Patients will have a cardiopulmonary stress test (treadmill test) and a 6-minute walk test, both before pacemaker implantation and then 6 months afterward. Also before and after pacemaker implantation, patients will complete the Minnesota Living with Heart Failure Questionnaire, regarding the impact of heart failure on patients' lives. The follow-up visit will take 3 to 4 hours.

Key facts

Study ID

NCT00359372

Run by

National Heart, Lung, and Blood Institute (NHLBI)

People needed

180

Starts

2006-07-28

Expected to finish

2007-05-29

Last updated by the study team

2017-07-02

Who can join

Age: 18 and older. Sex: any. Healthy volunteers: not accepted.

You may qualify if…

• LV dysfunction with an LV ejection fraction less than or equal to 35% (by clinical echocardiography, cardiac catheterization, radionuclide ventriculography, or MRI).
• New York Heart Association (NYHA) class III or IV functional status
• QRS interval greater than or equal to 120msec (measured on clinical ECG)
• Optimal pharmacological therapy for heart failure with at least 1 month on an ACE-inhibitor or angiotensin II receptor blocker (ARB) and if on a beta blocker, 3 months on a stable dose of a beta blocker. Patients need to be taking their medicines consistently to be enrolled in this study.

You may not qualify if…

• Coronary artery bypass graft surgery or percutaneous coronary intervention within 60 days of enrollment.
• Chronic medically refractory atrial tachyarrhythmias
• History of medical non-compliance
• Women who are pregnant or not using medically acceptable birth control (since the x-rays used to guide pacemaker therapy may increase the risk to the fetus and the fetal risks of gadolinium are not well known).
• Contraindication to MRI scanning including patients with the following devices:
• i. Central nervous system aneurysm clips
• ii. Implanted neural stimulator
• iii. Implanted cardiac pacemaker or defibrillator prior to enrollment
• iv. Cochlear implant
• v. Ocular foreign body (e.g. metal shavings)
• vi. Insulin pump
• vii. Metal shrapnel or bullet
• Contraindications to MRI contrast agent administration:
• i. lactating women
• ii. patients with hemoglobinopathies
• iii. severe renal disease (CrCl less than 20 ml/min)
• Baseline 6-minute hall walk distance more than 450 meters (to exclude patients who are unlikely to truly have NYHA class III to IV heart failure)
• Enrollment in any concurrent study that may confound the results of this study
• Life expectancy less than 6 months because of other medical conditions.
• Age less than 18 years since this disease is not prevalent in children.

Where it is running

• Mid-Atlantic Associates — Baltimore, Maryland, United States
• Suburban Hospital — Bethesda, Maryland, United States
• National Heart, Lung and Blood Institute (NHLBI), 9000 Rockville Pike — Bethesda, Maryland, United States

Full record on ClinicalTrials.gov

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