An interventional study of Bilateral Sequential Stellate Ganglion Block in POTS - Postural Orthostatic Tachycardia Syndrome, sponsored by University Medical Centre Ljubljana. Not yet recruiting. Open to participants aged 18 Years to 65 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-09-24.
Sponsored by University Medical Centre Ljubljana · Not applicable, Interventional, and Treatment
RESET-POTS is a pilot study for adults with postural orthostatic tachycardia syndrome (POTS), a condition that can cause a rapid increase in heart rate, dizziness, weakness, fatigue and other symptoms when standing. The study has two parts. In the first part, patients with POTS and healthy volunteers will undergo several tests to better understand how POTS affects heart rate and blood pressure, the autonomic nervous system, hormones, metabolism, blood sugar regulation, brain and muscle oxygenation, and quality of life. In the second part, eligible patients with POTS will receive a stellate ganglion block, a procedure in which a local anaesthetic is injected near nerves in the neck that are involved in sympathetic nervous system activity. The procedure will be performed on the right and left sides on separate days. Participants will then be reassessed about 2 weeks and 3 months later. The main goals are to determine whether the study procedures are practical and well tolerated, whether the nerve block can be performed successfully and safely, and whether there are signs of changes in POTS-related body functions and symptoms.
Postural orthostatic tachycardia syndrome (POTS) is a condition in which standing causes an excessive increase in heart rate together with symptoms such as dizziness, palpitations, weakness, fatigue, exercise intolerance and difficulties with concentration. POTS is a heterogeneous condition, meaning that the underlying abnormalities may differ considerably between individuals. Changes in autonomic nervous system activity, regulation of blood volume and hormones, metabolism, and blood flow or oxygen delivery to the brain may all contribute to symptoms. However, the relationships between these abnormalities are not fully understood, and currently available treatments do not adequately control symptoms in all patients. RESET-POTS therefore focuses on adults with confirmed POTS who remain symptomatic despite standard non-pharmacological and pharmacological management.
The study consists of two phases. In Phase 1, patients with POTS and healthy volunteers will undergo detailed testing designed to provide a broad picture of how the body responds to standing. This includes a 10-minute standing test with continuous measurement of heart rate and blood pressure, assessment of heart-rate variability, and measurement of breathing and oxygenation in the brain and skeletal muscle. Blood samples obtained while lying down and standing will be used to examine hormones and other markers involved in sympathetic nervous system activity, blood-volume regulation and endocrine function. Additional assessments include glucose and insulin responses, continuous glucose monitoring, resting and standing energy expenditure, body composition, muscle strength, cortisol patterns and questionnaires assessing symptoms and quality of life. The aim of this phase is to identify physiological patterns that may help explain why POTS differs between individuals and to identify measurements that could be useful in future treatment studies.
In Phase 2, eligible patients with POTS will receive a stellate ganglion block (SGB). The stellate ganglion is a group of nerves in the neck that forms part of the sympathetic nervous system, which helps regulate heart rate, blood vessels and the body's response to stress. During SGB, a local anaesthetic is injected under ultrasound guidance near these nerves to temporarily reduce sympathetic nerve activity. In RESET-POTS, the right and left sides will be treated during separate procedures approximately 3-7 days apart. Participants will be monitored during and after each procedure. Changes in skin temperature and clinical signs will be used to confirm whether the nerve block has produced the expected physiological effect.
Participants who undergo SGB will repeat relevant assessments approximately 2 weeks and 3 months after completion of the bilateral intervention. The study is not designed to determine conclusively whether SGB is an effective treatment for POTS. Instead, its main goals are to determine whether this approach can be studied safely and practically, whether participants can complete the planned testing and follow-up, whether the SGB procedures can be performed successfully, and whether the collected physiological measurements are sufficiently reliable for a larger future trial. Changes in heart-rate responses to standing, autonomic nervous system activity, hormonal and metabolic measures, brain and muscle oxygenation, and POTS symptoms will also be explored.
The results will be used to design a future randomized, sham-controlled clinical trial. In particular, RESET-POTS aims to help determine which patients may be most suitable for sympathetic nervous system-targeted treatment, which objective measurements should be used to assess treatment effects, and how a larger trial should be designed to distinguish the physiological effects of SGB from placebo and expectancy effects.
136 studies on the registry are indexed under Postural Orthostatic Tachycardia Syndrome; 42 are open to participants now.
This study's planned enrollment of 30 is below the median of 36 across 102 interventional studies indexed under Postural Orthostatic Tachycardia Syndrome.
Browse Postural Orthostatic Tachycardia Syndrome studies →University Medical Centre Ljubljana is the lead sponsor of 296 studies on the registry; 72 are open to participants now.
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Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Participants with POTS:
Healthy control participants:
Exclusion Criteria
For all participants:
Additional exclusion criteria for the stellate ganglion block phase:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Clinically significant
Judged by the study doctor to matter for your health or for the study. It is a doctor’s decision, so ask the study team if you are unsure whether something counts.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraindication
A reason a treatment, test or procedure should not be given to a particular person, such as an allergy, another illness or a medicine they take.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hypersensitivity
An allergy, or another reaction of the immune system, to a substance. “Hypersensitivity to the study drug” means a known allergic reaction to it — not every side effect a medicine can have.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants with confirmed postural orthostatic tachycardia syndrome will undergo comprehensive multidomain phenotyping. Participants who meet the eligibility criteria for the interventional phase will subsequently undergo bilateral sequential ultrasound-guided stellate ganglion block, with the right and left sides treated in separate sessions 3-7 days apart. Follow-up assessments will be performed approximately 14 days and 3 months after completion of the bilateral intervention.
Procedure: Bilateral Sequential Stellate Ganglion Block
Healthy control participants will undergo the same baseline multidomain phenotyping assessments as the POTS group, where applicable, to provide comparative physiological data. Healthy controls will not undergo stellate ganglion block or post-intervention follow-up assessments.
Participants will undergo ultrasound-guided stellate ganglion block (SGB) on both sides, performed as two separate procedures 3-7 days apart. The right side will be treated first, followed by the left side. Each block will be performed under real-time ultrasound guidance, primarily at the C6 level, using levobupivacaine 0.5% (8 mL per side), without exceeding the recommended maximum dose. Participants will be monitored during and after each procedure. Technical success of the block will be assessed using infrared thermography and supportive clinical signs of sympathetic blockade.
Also known as: SGB
Completion of the Core Phase 1 Phenotyping Protocol
Percentage of enrolled participants who complete the predefined core multidomain Phase 1 phenotyping protocol.
Time frame: End of Phase 1 phenotyping (before stellate ganglion block)
Completeness of Phase 1 Phenotyping Data
Proportion of participants with complete and interpretable data across the predefined phenotyping domains. Data completeness will be assessed to determine the feasibility of using the multidomain assessment battery in a future randomized trial.
Time frame: End of Phase 1 phenotyping (before stellate ganglion block)
Progression of Patients With POTS to the Interventional Phase
Percentage of eligible patients with POTS who proceed from Phase 1 phenotyping to Phase 2 and undergo stellate ganglion block.
Time frame: At initiation of Phase 2 (stellate ganglion block)
Completion of Both Planned Stellate Ganglion Block Procedures
Percentage of participants entering Phase 2 who complete both the right and left stellate ganglion block procedures as planned.
Time frame: From the first stellate ganglion block to the second block, performed 3-7 days later
Completion of First Follow-up
Percentage of participants undergoing bilateral stellate ganglion block who complete the planned early follow-up assessment.
Time frame: Approximately 14 days after completion of bilateral stellate ganglion block
Completion of Second Follow-up
Percentage of participants undergoing bilateral stellate ganglion block who complete the planned final follow-up assessment.
Time frame: Approximately 3 months after completion of bilateral stellate ganglion block
Incidence of Adverse Events
Number and percentage of participants experiencing adverse events during the interventional phase, including the type and severity of events and their relationship to stellate ganglion block. Procedure-related events of particular interest include dysphonia, dysphagia, hoarseness, brachial plexus block, phrenic nerve involvement, hematoma, vasovagal reaction, infection, allergic reaction, inadvertent intravascular injection, local anesthetic systemic toxicity, and pneumothorax.
Time frame: From the first stellate ganglion block through the final follow-up approximately 3 months after bilateral stellate ganglion block
Technical Success of Stellate Ganglion Block
Percentage of performed stellate ganglion block procedures meeting the predefined criteria for technical success. Technical success will be based primarily on thermographic evidence of ipsilateral sympathetic blockade, supported by clinical signs where present.
Time frame: Within 30 minutes after each stellate ganglion block procedure
Change in Orthostatic Heart Rate Increment
Change from baseline in the maximum increase in heart rate from the supine position during the orthostatic test.
Time frame: Baseline and approximately 14 days and 3 months after completion of bilateral stellate ganglion block
Change in Mean Standing Heart Rate
Change from baseline in RMSSD derived from heart-rate variability analysis during standardized orthostatic testing.
Time frame: Baseline and approximately 14 days and 3 months after completion of bilateral stellate ganglion block
Change in Standard Deviation of Normal-to-Normal Intervals (SDNN)
Change from baseline in SDNN derived from heart-rate variability analysis during standardized orthostatic testing.
Time frame: Baseline and approximately 14 days and 3 months after completion of bilateral stellate ganglion block
Change in Standing Plasma Metanephrine and Normetanephrine
Change from baseline in plasma metanephrine and normetanephrine measured after 10 minutes of orthostatic test.
Time frame: Baseline and approximately 14 days and 3 months after completion of bilateral stellate ganglion block.
Change in Orthostatic Cerebral Tissue Saturation Index
Cerebral tissue saturation index (TSI) will be measured continuously using near-infrared spectroscopy sensors placed over the frontal cortex. Change in the orthostatic cerebral TSI response from the pre-intervention baseline visit to follow-ups will be expressed in percentage points.
Time frame: Baseline and approximately 14 days and 3 months after completion of bilateral stellate ganglion block
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Plan to share: Undecided
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This study is not yet recruiting, as verified in Aug 2026. You cannot join it, but the record below documents what was studied.
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Postural Orthostatic Tachycardia Syndrome →
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