Postural Orthostatic Tachycardia Syndrome
Conditions
Keywords
POTS
Brief summary
The study compares three treatment modalities in a human model of Postural orthostatic tachycardia syndrome (POTS): beta-blockers, I(f)-blockers, and placebo.
Detailed description
Elevated heart rate may lead to cardiac disease in the long-term. Therefore, drugs lowering heart rate are useful. Beta-blockers are an established treatment modality. They not only lower heart rate but also contractility, which might be undesirable in certain tachycardic disorders. Postural orthostatic tachycardia syndrome (POTS) patients complain about dizziness, weakness, headache, lightheadedness, fatigue, nausea, and presyncope. In some patients there is elevated heart rate even during supine rest. In POTS patients it is preferable to lower heart rate without reducing cardiac contractility which can be achieved by using so-called I(f)-blockers. Thus, they might be superior to beta-blockers in POTS. In our study, we artificially generate POTS in healthy male subjects for about 48 hours. We want to compare the cardiovascular effects and orthostatic tolerance of the following treatments: beta-blocker, I(f)-blocker, and placebo. Moreover, we will quantify changes in cardiovascular autonomic regulation brought about by I(f)-blockade versus placebo.
Interventions
DRUGbeta-blocker (Metoprolol)
Metoprolol 95 mg once per day
DRUGI(f)-blocker (ivabradine)
ivabradine 7.5 mg once per day
DRUGPlacebo
matching appearance
Sponsors
Charite University, Berlin, Germany
Hannover Medical School
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Subject, Investigator)
Eligibility
Sex/Gender
MALE
Age
18 Years to 40 Years
Healthy volunteers
Yes
Inclusion criteria
* healthy male * age 18-40 years * BMI: 18-30 kg/m² * arterial blood pressure \<=160/100 mm Hg * co-operativity * voluntariness
Exclusion criteria
* conditions in which treatment might be ineffective or insecure * co-medication within the last 4 weeks * participation in another clinical trial within the last 4 weeks * unability to understand the study's aim * drug or alcohol abuse * secondary hypertension * creatinine \> 130 μM (1.47 mg/dl) * GOT/GPT \> 2 times normal * GGT \> 3 times normal * contraindications against reboxetine, beta-blocker, ivabradine * asthma, psoriasis * diabetes * heart failure (NYHA III or IV) * coronary artery disease * peripheral occlusive disease * cerebrovascular disease * ventricular extrasystoles (Lown III-V) * atrial fibrillation * resting heart rate \<60/min * neurologic/psychiatric disorder * pulmonary hypertension * dysthyroid metabolism
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Sub-study 'Orthostatic tolerance': Change in heart rate after 20 mins of passive orthostasis. Sub-study 'Sympathetic system': arterial pressure related heart rate | 12-18 hours |
Secondary
| Measure | Time frame |
|---|---|
| 'Orthostatic tolerance': Hemodynamics during head-up tilt. Time to presyncope. | 12-18 hours |
| 'Sympathetic system': Muscle sympathetic nerve activity (MSNA). | 12-18 hours |
Countries
Germany
Contacts
Primary ContactHeidrun Mehling, MD
Backup ContactJens Tank, MD
Outcome results
None listed