Predicting Response to Cardiac Resynchronization Therapy in Heart Failure
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.
研究概览
详细说明
研究类型
注册
联系人和位置
学习地点
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Maryland
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Baltimore、Maryland、美国
- Mid-Atlantic Associates
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Bethesda、Maryland、美国、20814
- Suburban Hospital
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Bethesda、Maryland、美国、20892
- National Heart, Lung and Blood Institute (NHLBI), 9000 Rockville Pike
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参与标准
资格标准
适合学习的年龄
接受健康志愿者
有资格学习的性别
描述
- INCLUSION and EXCLUSION CRITERIA
No one will be excluded from this study based on race, gender, and ethnicity.
INCLUSION CRITERIA
- 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.
EXCLUSION CRITERIA
- 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.
学习计划
研究是如何设计的?
合作者和调查者
出版物和有用的链接
研究记录日期
研究主要日期
学习开始
研究完成
研究注册日期
首次提交
首先提交符合 QC 标准的
首次发布 (估计)
研究记录更新
最后更新发布 (实际的)
上次提交的符合 QC 标准的更新
最后验证
更多信息
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