Mechanisms, Safety and Efficacy of Optimising Pacemaker Heart Rate for Contractility: Effects on Walk Time, Cardiac Remodelling and Quality of Life
试验速览
- 阶段
- 2 期
- 状态
- 招募中
- 入组人数
- 400
- 试验地点
- 1
- 主要终点
- Treadmill walk time
研究概览
简要总结
The investigators have demonstrated that they can reliably identify an optimum heart rate range for contractility of the left ventricle in patients with chronic heart failure (CHF). They have also demonstrated in an acute cross-over and a small parallel group feasibility study that keeping the heart rate in this range (versus standard rate-response programming) in patients with CHF is associated with increased exercise time on a treadmill (around 60s or 10%). They now want to explore in a randomised, placebo-controlled 3-arm parallel group trial whether optimal programming versus standard rate-response programming versus no rate-response programming for 6 months leads to appreciable improvements in exercise time and quality of life, while having no adverse effects on left ventricular function and battery longevity and what the mechanisms of this might be.
400 patients with CHF and a pacemaker will undergo the non-invasive echocardiographic assessment to establish the force frequency relationship and the optimal heart rate for contractility. They will then perform a treadmill walk test, complete quality of life questionnaires and be offered the opportunity to participate in a series of mechanistic substudies. They will then be randomised to optimal rate-response settings, standard rate response settings or no rate-response settings and followed up at 6 months at which point the tests will be repeated.
详细描述
Detailed Description:
Design: This will be a randomised, double-blind 'placebo' controlled trial of optimised programming versus standard rate-response settings, aiming to determine whether the short term improvements translate into longer term benefits.
Study participants: 400 adult patients (>18years).
Study Procedures: Patients attending the heart failure clinic, the pacemaker clinic or previous research participants will be approached with a standard letter and information sheet and then a telephone call to make sure any remaining questions are answered.
Patients agreeing to participate will attend the clinical research facility (CRF) and will be asked to sign a consent form. Each patient will have a standard device check, check of their demographic data, and co-morbidities. The investigators will record a resting cardiac ultrasound, and measure the force frequency relationship (FFR) to determine critical heart rate (HR), and the optimal range of HR rise. All images will be stored for offline analysis. Participants will then be asked to do a symptom-limited walk test on the treadmill (until they cannot do any more). At this first visit, participants will also complete quality of life questionnaires and be invited to participate in substudies including cardiac magnetic resonance, blood tests, tests of autonomic dysfunction. All of these activities will take place in the Clinical Research Facility at Leeds General Infirmary.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Treatment
- 盲法
- Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
盲法说明
Only the technician doing the programming will know how the pacemaker has been set.
入排标准
- 年龄范围
- 18 Years 至 —（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Left ventricular systolic dysfunction (LVEF<50%),
- •Cardiac pacemaker,
- •Able to perform a peak exercise test,
- •Willing and able to give informed consent.
排除标准
- •Angina pectoris symptoms limiting exercise tolerance,
- •Unstable heart failure symptoms (medical therapy changes in last three months), Poor image quality,
- •Calcium channel blockers (CCBs).
结局指标
主要结局
Treadmill walk time
时间窗: 6 months
Time walked during a standard incremental treadmill test
次要结局
- Quality of life 1(6 months)
- Clinical composite score(6 months)
- Wall stress by cardiac MRI(6 months)
- Quality of life 2(6 months)
- Cardiac function during exercise measured by LVEF on echocardiogrpahy(6 months)
- Autonomic dysfunction(6 months)
研究者
Klaus K Witte, MD
Prinicipal Investigator
University of Leeds