Implications of Paced Heart Rate on Central Blood Pressure in Sick Sinus Syndrome Patients With Hypertension: a Randomised Crossover Study
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 22
- 试验地点
- 1
- 主要终点
- Central systolic blood pressure
研究概览
简要总结
Central (aortic) blood pressure predicts heart, brain and kidney complications more reliably than the usual peripherally measured blood pressure. Heart rate has a strong and sometimes counter-intuitive influence on central blood pressure. Pacemakers implanted due to sick sinus syndrome (SSS) are typically programmed anywhere between 55-75 beats per minute (bpm), yet it is unclear which rate gives hypertensive pacemaker recipients the most favourable central hemodynamics.
This single-center, randomized, single-blind, two-period cross-over trial will enrol 20 adults (18-80 years) who already carry a dual-chamber pacemaker for SSS, are in sinus rhythm, and have medication-controlled arterial hypertension. Each participant will complete two eight-week pacing periods in random order:
- "Slow" period - pacemaker lower-rate set to 55 bpm.
- "Fast" period - pacemaker lower-rate set to 75 bpm.
A two-week wash-out at the device's usual settings separates the periods. At baseline and after each intervention the team will perform non-invasive pulse-wave analysis (SphygmoCor XCEL) to obtain central systolic blood pressure (primary endpoint) and arterial stiffness indices such as augmentation index and pulse-wave velocity (secondary endpoints). Pacemaker function, symptoms and safety events are reviewed at every visit; settings can be adjusted by ±5 bpm if troublesome symptoms occur.
The study will provide the first long-term evidence on how fixed pacing rates modulate central blood pressure in real-world SSS patients with hypertension, potentially guiding clinicians toward the optimal programming strategy.
详细描述
Scientific background and rationale Arterial hypertension remains the leading modifiable contributor to cardiovascular morbidity. Unlike brachial pressure, central (aortic) systolic pressure directly loads the left ventricle and cerebral and renal arteries. Epidemiological data show that central pressure is more closely associated with left-ventricular hypertrophy, carotid atherosclerosis and clinical events than peripheral pressure. Heart rate (HR) alters the timing of pulse-wave reflections and can therefore change central pressure in ways that are not apparent from arm-cuff readings.
Pharmacological HR reduction (e.g., ivabradine) has been shown to raise central systolic pressure even while lowering brachial pressure, whereas β-blockers exert mixed HR-dependent and HR-independent effects. In acute pacing studies, lowering HR from 80 bpm to ~60 bpm reduced brachial pressure but left central pressure unchanged; allowing HR to fall to ~50 bpm sometimes lowered or sometimes raised central pressure depending on study design. No prospective trial has tested whether a chronically lower versus higher pacemaker rate produces a durable difference in central hemodynamics in patients who require pacing for SSS.
Objectives Primary: Compare clinic-measured central systolic blood pressure after 8 weeks of pacing at 55 bpm versus 75 bpm.
Secondary: Compare additional central hemodynamic indices (augmentation index, pulse pressure amplification, carotid-femoral pulse-wave velocity), brachial blood pressure, and frequency of pacing-related symptoms and atrial arrhythmias between the two settings.
Study design
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
- Single (Participant)
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
- •Age 18-80 years.
- •Dual-chamber pacemaker implanted ≥3 months for SSS.
- •Sinus rhythm; atrial pacing >80%, ventricular pacing <3% since last device check.
- •Medication-treated primary hypertension with clinic BP < 140/90 mmHg and home BP < 135/85 mmHg.
- •Able to provide informed consent and comply with procedures.
排除标准
- •Significant AV block, paced QRS ≥ 130 ms, >3 antihypertensives, digoxin or class Ic/III/IV antiarrhythmics, frequent atrial tachyarrhythmia (>3% AMS episodes), coronary intervention on >1 vessel, LVEF ≤ 40%, CRT or ICD, significant valvular disease, congenital heart disease, BMI ≥ 35 kg/m², diabetes with complications or on insulin, advanced renal, hepatic or pulmonary disease, systemic inflammatory disease, malignancy under recent active therapy, pregnancy or lactation, substance misuse, or inability to complete follow-up.
研究组 & 干预措施
"Slow" arm
Pacemaker base rate set at 55 bpm
干预措施: Pacemaker and defibrillator (Device)
"Fast" arm
Pacemaker base rate set at 75 bpm
干预措施: Pacemaker and defibrillator (Device)
结局指标
主要结局
Central systolic blood pressure
时间窗: After each 8-week intervention period (at week 8 and week 18 of study participation)
Central (aortic) systolic blood pressure measured non-invasively using pulse wave analysis (SphygmoCor XCEL) with brachial cuff acquisition and generalized transfer function to derive central waveforms. Measurements taken in standardized seated position in clinical setting.
次要结局
- Central diastolic blood pressure(After each 8-week intervention period (at week 8 and week 18 of study participation))
- Augmentation index(After each 8-week intervention period (at week 8 and week 18 of study participation))
- Pulse wave velocity(After each 8-week intervention period (at week 8 and week 18 of study participation))
- Brachial blood pressure(After each 8-week intervention period (at week 8 and week 18 of study participation))
- Pulse pressure amplification(After each 8-week intervention period (at week 8 and week 18 of study participation))
研究者
Priit Kampus
Associate Professor Priit Kampus
University of Tartu