Vagal Stimulation in POTS

Vanderbilt University Medical Center

Status and phase: Active, not recruiting; Phase 1

Conditions: Postural Tachycardia Syndrome

Treatments: Drug: Pyridostigmine Pill; Device: Vagal stimulation; Drug: Galantamine Pill; Drug: placebo sugar pill; Device: Sham vagal stimulation

Study type: Interventional

Funder types: Other

Identifiers

NCT03124355

6111

Details and patient eligibility

About

The purpose of this study is to investigate how the electrical stimulation of a nerve in the skin of the earlobe (transcutaneous vagal nerve stimulation), alone or in combination with two medications (galantamine and pyridostigmine), affects the way the autonomic (involuntary) nervous system controls heart rhythm, symptoms on standing, and inflammatory markers in female patients with postural tachycardia syndrome (POTS). The study consists of 2 parts: a screening (1-2 study days), and 3 testing days. The study will take 5 days total and about 16 participants will be screened for the study. The investigators estimate 13 will be eligible to participate in all of the study days.

Full description

This study will test the hypothesis that impairment of the parasympathetic nervous system contributes to the symptoms of POTS and that stimulation of this part of the nervous system improves the excessive increase in heart rate, standing tolerance and inflammation in patients with POTS. For this purpose, the investigators will use electrical stimulation of a nerve in the skin of the earlobe (transcutaneous vagal nerve stimulation) and two medications that increase the levels of acetylcholine (a neurotransmitter) in the central or peripheral nervous system (galantamine and pyridostigmine, respectively) to increase the activity of the parasympathetic nervous system.

Screening Procedures: Potential participants will be screened in the Vanderbilt Autonomic Dysfunction Center (ADC). Medications affecting heart rate, blood pressure, blood volume, inflammatory markers and the autonomic nervous system will be withdrawn for at least five half-lives before studies. Patients will undergo a complete history and physical examination, ECG, routine clinical laboratory analyses and a blood pregnancy test for women of childbearing potential. Autonomic testing including a posture study with plasma catecholamines is then performed to determine if they meet the inclusion/exclusion criteria.

Eligible participants will be studied on three separate days in a randomized, double-blind, crossover fashion. On each testing day, patients will be given one dose of the study medication (either pyridostigmine, galantamine or placebo pill), and then will have two tilt table tests (a motorized table with a footboard that moves to an upright position): one with the vagal stimulation and one with sham electrical stimulation. Heart rhythm, blood pressure and the amount of fluid in the body (body impedance) will be monitored during studies. Blood samples (up to a total of 2 tablespoons per study day) will also be collected. The order of the study days and tilt tests will be decided at random, like the toss of a coin. Each study day will last about 5 hours.

Enrollment: 11 patients

Sex: Female

Ages: 18 to 45 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Female subjects of 18-45 years, with Postural Tachycardia Syndrome (POTS) as defined by a heart rate increase ≥30 bpm from supine within 10 min of standing or head-up tilt in the absence of orthostatic hypotension, with chronic symptoms (> 6 months), and in the absence of other acute cause of orthostatic tachycardia.
• Subjects able and willing to provide informed consent

Exclusion criteria

• Pregnancy.
• Medical conditions that can explain postural tachycardia (e.g., dehydration, medications).
• Patients who are bedridden or chair-ridden
• Subjects taking any medication known to affect autonomic function or inflammatory markers (e.g. corticosteroids) who could not discontinue them before study participation.
• Conditions associated with chronic inflammatory processes which in the investigator's opinion would affect the interpretation of the results. Examples may include smoking, diabetes, BMI>30 kg/m2, current infections or cancer.
• Other factors which in the investigator's opinion would prevent the subject from completing the protocol.

Trial design

Primary purpose: Basic Science

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: Double Blind

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11 participants in 3 patient groups

Placebo pill with vagal/sham stimulation

Experimental group

Description:

Patients will receive a single oral dose of placebo sugar pill, and 1.5-2 hours later they will have two tilt table tests: one with vagal stimulation and one with sham vagal stimulation

Treatment:

Device: Sham vagal stimulation

Drug: placebo sugar pill

Device: Vagal stimulation

Pyridostigmine with vagal/sham stimulation

Experimental group

Description:

Patients will receive a single oral dose of pyridostigmine pill 30 mg, and 1.5-2 hours later they will have two tilt table tests: one with vagal stimulation and one with sham vagal stimulation

Treatment:

Device: Sham vagal stimulation

Device: Vagal stimulation

Drug: Pyridostigmine Pill

Galantamine with vagal/sham stimulation

Experimental group

Description:

Patients will receive a single oral dose of galantamine pill 8 mg, and 1.5-2 hours later they will have two tilt table tests:one with vagal stimulation and one with sham vagal stimulation

Treatment:

Device: Sham vagal stimulation

Drug: Galantamine Pill

Device: Vagal stimulation