Optimising Pacemaker Therapy Using Multi-point Pacing (the OPT-MPP Study)
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 23
- 试验地点
- 1
- 主要终点
- Force frequency curve (phase 1)
研究概览
简要总结
Recently, the introduction of quadripolar left ventricular leads (one with four pacing poles) has allowed the opportunity to pace the lateral (back) of the heart from several points at once using a single lead (multi-point pacing - MPP). Although it seems logical that electrical beginning at several points on the left ventricular wall should improve coordination of the heart, there is no consistent response in terms of improved remodeling (cardiac structure and function) or composite scores of patient-related status. The technology has a further disadvantage that it leads to accelerated battery drain, with on average one year less longevity over the lifetime of the device.
Aims are:
- to explore the effect of MPP on the force-frequency relationship,
- to examine the effects of MPP on exercise capacity measured by treadmill walk time and whether these are related to the FFR response to MPP in individual patients,
- establish whether the acute contractile response is maintained to 6 months after the implant procedure and
- determine whether the acute contractile response to MPP is associated with subsequent beneficial remodeling over a further six months.
详细描述
Cardiac function during exercise Cardiac output is a function of stroke volume (the volume of blood ejected with each beat) and heart rate. During exercise cardiac output must rise to supply exercising muscles. This occurs by an increase in both heart rate and stroke volume. Limitations to heart rate rise (chronotropic incompetence (CI)) or stroke volume increases (contractility) or a combination of both might contribute to lower cardiac output during exercise.
Increases in contractility during exercise are under two major influences: depolarization-rate dependent (heart rate dependent), and catecholamine-dependent. Normal increases in contractility during exercise require both to be functioning normally. As mentioned, the catecholamine system is chronically overactive in CHF such that there is down-regulation of receptors making the sympathetic system less sensitive and responsive. The depolarization-rate dependent (catecholamine-independent) mechanism, whereby increases in heart rate lead to increases in the force of contraction known as the Treppe phenomenon, or the force frequency relationship (FFR), was described by Bowditch in the late 19th century, and is thought to be impaired in CHF such that contractility in heart failure does not rise normally with increases in heart rate and in fact reduces once heart rate rises above a threshold.
How to determine force-frequency relationship in humans
The investigators have established a reliable, reproducible and non-invasive method by which to assess the FFR in patients with pacemaker devices. The investigators subsequently demonstrated that optimizing heart rate rise to within the range for optimal contractility is associated with acute improvements in exercise capacity. The FFR assessment protocol is described below.
This study will have two phases:
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)
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
- •Symptomatic heart failure due to left ventricular systolic dysfunction (LVEF<35%)
- •Due to (or just undergone) undergo CRT implantation
- •Able to perform a peak exercise test
- •Willing and able to give informed consent
排除标准
- •Atrial fibrillation
- •Angina pectoris symptoms limiting exercise tolerance
- •Unstable heart failure symptoms (medical therapy changes in last three months
- •Poor imaging quality such that analysis is unreliable
- •Calcium channel blockers (CCBs)
研究组 & 干预措施
Standard settings
Usual pacing programming
干预措施: Standard settings (Device)
Multi-point pacing
MPP programming
干预措施: Multi-point pacing (Device)
结局指标
主要结局
Force frequency curve (phase 1)
时间窗: Acute - cross-over phase at 6 weeks
Contractility curve over heart rate range
次要结局
- Quality of life (EQ5D-5L)(From 6 months to 12 months following implant)
- Treadmill walk time (phase 2)(From 6 months to 12 months following implant - chronic parallel group phase)
- Quality of life (MLWHF)(From 6 months to 12 months following implant)
- Force frequency curve (phase 1)(Acute - cross-over phase at 6 months)