The Influence of Iatrogenic Chronotropic Incompetence on Exercise Tolerance in Pacemaker Patients With Chronic Heart Failure.
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 40
- 试验地点
- 1
- 主要终点
- Maximal Oxygen Consumption (Peak VO2)
研究概览
简要总结
To examine the effects of heart rate reduction on exercise capacity in control subjects and patients with chronic heart failure.
详细描述
Original proposal: Does iatrogenic chronotropic incompetence lead to impaired exercise capacity in patients with CHF
Aim The aim of this proposal is to examine the effects of iatrogenic CI on exercise capacity in control subjects and patients with chronic heart failure.
Hypothesis Iatrogenic chronotropic incompetence does not contribute significantly to reductions in exercise capacity in patients with heart failure or control subjects with pacemakers.
Methods REDUCING HEART RATE AT REST AND EXERCISE In patients with sinus rhythm, the present proposal utilizes a heart failure medication called ivabradine. This agent, an If channel blocker, specifically targets the sinus node leading to a slower heart rate. The agent is approved and licensed for use in patients with heart failure at the doses proposed. Ivabradine slows the sinus rate with none of the peripheral effects of beta-blockers. Heart rate lowering with ivabradine improves cardiac function, and outcomes related to the degree of bradycardia achieved.
In patients with atrial fibrillation, the present proposal will recruit patients with CRT and atrial fibrillation that have undergone atrio-ventricular node (AVN) ablation to improve the efficacy of CRT. Patients who have undergone AVN ablation are dependent upon their pacemaker, and we can therefore control their heart rate accurately.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Crossover
- 主要目的
- Treatment
- 盲法
- Double (Participant, Investigator)
入排标准
- 年龄范围
- 18 Years 至 90 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- 未提供
排除标准
- •We will exclude subjects with musculoskeletal disorders limiting exercise capacity, patients with peripheral vascular disease, those with inflammatory disorders such as rheumatoid arthritis, and airways disease. Other exclusions include contraindications to ivabradine use such as severe hepatic impairment, significant renal impairment (creatinine clearance <15ml.min-1), and long QT syndrome. We will only include patients able to give informed written consent, which will be obtained in all subjects.
研究组 & 干预措施
Placebo
Subjects are given a placebo capsule (double-blinded) to take 90 minutes prior to the cardiopulmonary exercise test.
干预措施: Placebo (Drug)
Ivabradine
Subjects are given an ivabradine capsule (double-blinded) to take 90 minutes prior to the cardiopulmonary exercise test.
干预措施: Ivabradine (Drug)
Atrial fibrillation
Subjects are (double blind) randomised to either a low base pacing rate (30) or a standard base rate (60), with rate adaptive algortithms switched on.
干预措施: Atrial fibrillation (Other)
结局指标
主要结局
Maximal Oxygen Consumption (Peak VO2)
时间窗: Each test lasts up to 20 minutes
Cardiopulmonary exercise testing performance - measuring peak oxygen uptake during a treadmill CPEX test. Subjects were exercised using the Bruce protocol, modified by the addition of a "stage 0" at onset consisting of 3 min of exercise at 1.61 km·h-1 (1 mile·h-1) with a 5% gradient. Expired air was collected and metabolic gas exchange analysis performed in order to measure the maximal oxygen consumption (peak VO2) (Sensormedics, Yorba Linda, California). The CPX equipment was recalibrated before every exercise test. All test subjects were encouraged to exercise to exhaustion before starting the test, and no further motivation or instructions were given.
次要结局
未报告次要终点
研究者
Haqeel Jamil
Cardiology Registrar and Clinical Research Fellow
University of Leeds