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Cardiovascular Effects of Selective I(f)-Channel Blockade

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00865917
Recruitment Status : Unknown
Verified March 2009 by Hannover Medical School.
Recruitment status was:  Recruiting
First Posted : March 19, 2009
Last Update Posted : March 19, 2009
Charite University, Berlin, Germany
Information provided by:
Hannover Medical School

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.

Condition or disease Intervention/treatment Phase
Postural Orthostatic Tachycardia Syndrome Drug: beta-blocker (Metoprolol) Drug: I(f)-blocker (ivabradine) Drug: Placebo Phase 2

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.

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 40 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double (Participant, Investigator)
Primary Purpose: Basic Science
Official Title: Einfluss Selektiver I(f)-Blockade Auf Orthostase-Toleranz Und Sympathikusaktivität Bei Gesunden
Study Start Date : November 2008
Estimated Primary Completion Date : November 2010
Estimated Study Completion Date : December 2010

Arm Intervention/treatment
Active Comparator: 1
Drug: beta-blocker (Metoprolol)
Metoprolol 95 mg once per day

Experimental: 2
Drug: I(f)-blocker (ivabradine)
ivabradine 7.5 mg once per day

Placebo Comparator: 3
Drug: Placebo
matching appearance

Primary Outcome Measures :
  1. Sub-study 'Orthostatic tolerance': Change in heart rate after 20 mins of passive orthostasis. Sub-study 'Sympathetic system': arterial pressure related heart rate [ Time Frame: 12-18 hours ]

Secondary Outcome Measures :
  1. 'Orthostatic tolerance': Hemodynamics during head-up tilt. Time to presyncope. [ Time Frame: 12-18 hours ]
  2. 'Sympathetic system': Muscle sympathetic nerve activity (MSNA). [ Time Frame: 12-18 hours ]

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Ages Eligible for Study:   18 Years to 40 Years   (Adult)
Sexes Eligible for Study:   Male
Accepts 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

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00865917

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Contact: Heidrun Mehling, MD +49(0)30 ext 94171296
Contact: Jens Tank, MD +49(0)511 ext 532 2723

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Franz-Volhard Centrum für Klinische Forschung Recruiting
Berlin, Germany, 13125
Contact: Heidrun Mehling, MD    +49(0)30 ext 94171296      
Medizinische Hochschule Hannover Recruiting
Hannover, Germany, 30625
Contact: Jens Tank, MD    +49(0)30 ext 5322723      
Contact: Karsten Heusser, MD    +49(0)30 ext 5322723      
Sponsors and Collaborators
Hannover Medical School
Charite University, Berlin, Germany
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Study Director: Jens Jordan, MD Hannover Medical School

Publications automatically indexed to this study by Identifier (NCT Number):
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Responsible Party: Heidrum Mehling, Dr. med., Franz-Volhard-Centrum für Klinische Forschung Identifier: NCT00865917     History of Changes
Other Study ID Numbers: CCB-CRC-07-02
First Posted: March 19, 2009    Key Record Dates
Last Update Posted: March 19, 2009
Last Verified: March 2009

Keywords provided by Hannover Medical School:

Additional relevant MeSH terms:
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Postural Orthostatic Tachycardia Syndrome
Arrhythmias, Cardiac
Heart Diseases
Cardiovascular Diseases
Cardiac Conduction System Disease
Pathologic Processes
Orthostatic Intolerance
Primary Dysautonomias
Autonomic Nervous System Diseases
Nervous System Diseases
Adrenergic beta-Antagonists
Anti-Arrhythmia Agents
Antihypertensive Agents
Autonomic Agents
Peripheral Nervous System Agents
Physiological Effects of Drugs
Adrenergic beta-1 Receptor Antagonists
Adrenergic Antagonists
Adrenergic Agents
Neurotransmitter Agents
Molecular Mechanisms of Pharmacological Action