Protocol Number: 03-N-0182

Title:

Propranolol for Syncope with Sympathoadrenal Imbalance

Number:

03-N-0182

Summary:

This study will examine the effectiveness of the drug propranolol in preventing fainting in patients with sympathoadrenal imbalance (SAI). SAI is a particular pattern of nervous system and chemical responses in which the blood vessels in skeletal muscles do not remain constricted appropriately during standing for a long time. This can lower blood pressure and cause fainting. Propranolol Inderal (registered trademark) is a Food and Drug Administration-approved drug that belongs to a class of drugs called beta-blockers. These drugs slow the heart rate and maintain blood pressure in certain situations.

Patients 18 years of age and older with SAI may be eligible for this study. Screening includes a tilt table test, described below, to determine if the patient has a particular chemical pattern in the blood.

Patients enrolled in the study take propranolol pills in increasing doses during the first week of the study to determine the proper dose for the individual. Then, the drug is stopped until the experimental phase of the study begins. In this phase, patients are randomly assigned to take either propranolol or placebo (look-alike pill with no active ingredient) for 4 days. On the fourth day, the patient undergoes a tilt table test to determine whether the treatment affects the patient's ability to tolerate tilt. For this test, the patient lies on a padded table with a motorized tilt mechanism that can move the patient from a flat position to an upright position in about 10 seconds. The patient remains upright for up to 45 minutes while the following measurements are taken:

- Arterial blood pressure monitoring and arterial blood sampling. A catheter (thin, plastic tube) is inserted into an artery in the elbow crease area of the arm or the wrist. This catheter allows continuous blood pressure monitoring and sampling of arterial (oxygenated) blood during the tilt test.

- Venous blood sampling and measurement of epinephrine and norepinephrine release. A catheter is inserted into a vein in each arm, one to collect venous (deoxygenated) blood samples, and the other to inject radioactive epinephrine (adrenaline) and norepinephrine (noradrenaline). These radioactive drugs, or ,tracers, allow measurement of the rate of release of the body's own norepinephrine and epinephrine into the bloodstream.

- Physiologic measurements. Blood pressure, heart rate, and EKG are measured continuously during the tilt test session, and blood flows and skin electrical conduction are measured intermittently. Blood flow is measured using sensors applied to the skin and a blood pressure cuff around the limb. For skin blood flow measurements, a laser beam scans the skin surface. The skin electrical conduction test measures how well the skin conducts electricity. This is measured through sensors placed on the fingers or other sites.

The effects of the test drug are allowed to wear off for 1 week, after which the entire tilt test procedure is repeated. Patients who were given propranolol for the first test session take placebo for the repeat session, and those who were given placebo take propranolol.

Sponsoring Institute:

National Institute of Neurological Disorders and Stroke (NINDS)

Recruitment Detail

Type: Follow-up Of Previously Enrolled Subjects Only

Gender: Male & Female

Referral Letter Required: Yes

Population Exclusion(s): Children

Eligibility Criteria: This study is not currently recruiting new subjects. If you have questions about participating in a study, please contact the Patient Recruitment and Public Liaison Office, CC.

Special Instructions:

This protocol is currently not recuiting Subjects.

Disease Category:

PROTICD

Keywords:

Beta-Adrenoceptors

Beta-Adrenoceptor Blocker

Neurocardiogenic Syncope

Chronic Orthostatic Intolerance

Neurocardiogenic

Dysautonomia

Autonomic Nervous System

Recruitment Keywords:

Nurocardiogenic Syncope

NCS

Sympathoadrenal Imbalance

SAI

Orthostatic Intolerance

Conditions:

Neurocardiogenic Syncope

Investigational Drug(s):

None

Investigational Device(s):

None

Contacts:

This study is not currently recruiting new subjects. If you have questions about participating in a study, please contact the Patient Recruitment and Public Liaison Office, CC.

Citations:

Robertson RM, Medina E, Shah N, Furlan R, Mosqueda-Garcia R.

Neurally mediated syncope: pathophysiology and implications for treatment. Am J Med Sci. 1999 Feb;317(2):102-9. Review.

PMID: 10037113

Goldstein DS, Holmes C, Frank SM, Dendi R, Cannon RO 3rd, Sharabi Y, Esler MD, Eisenhofer G. Cardiac sympathetic dysautonomia in chronic orthostatic intolerance syndromes.

Circulation. 2002 Oct 29;106(18):2358-65.

PMID: 12403667

Jacobs MC, Goldstein DS, Willemsen JJ, Smits P, Thien T, Dionne RA, Lenders JW. Neurohumoral antecedents of vasodepressor reactions. Eur J Clin Invest. 1995 Oct;25(10):754-61. PMID: 8557062

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