Sympathetic Nervous System Modulation in Hypertension

Study Overview
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Brief Summary
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This is a study of patients with high blood pressure who are already treated with an angiotensin converting enzyme inhibitor or receptor blocker and have achieved good or fair blood pressure control. The hypothesis is that addition of the beta-adrenergic receptor blocker, sustained-release metoprolol, will provide additional blockade of the sympathetic nervous system, thereby further improving left ventricular filling and blood pressure control.

Detailed Description
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Patients were to receive sympathetic cardiac innervation testing with I-123 MIBG at baseline and again after receiving a titrate dose of beta-blocker. Data were to be assesses by repeated measures testing.

Official Title
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Sympathetic Nervous System Modulation in Hypertension by Beta-adrenergic Blockade

Conditions
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Hypertension

Intervention / Treatment
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* Drug: Metoprolol Succinate


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Essential hypertension with blood pressure less than 140/90 on either an ACE inhibitor or angiotensin receptor blocker Exclusion Criteria: Known valvular heart disease of more than mild severity Known coronary artery disease defined by an angiographic coronary artery stenosis greater than or equal to 50% luminal diameter narrowing, acute or previous myocardial infarction, or previous coronary revascularization Known non-ischemic cardiomyopathy with left ventricular ejection fraction less than 50% Atrial fibrillation Current treatment with a β-adrenergic blocking drug or a calcium channel blocker Current treatment with a psychoactive or other drug known to alter 123I-MIBG uptake Participation in another research study within the prior 30 days A life-limiting disease process that is likely to preclude completion of study participation Pregnancy or breast feeding Inability or unwillingness to provide informed consent Baseline resting heart rate less than 65 beats per minute Diabetes Iodine allergy Unwilling to sign informed consent.

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: metoprolol succinate<br>Subjects will undergo I-123 MIBG testing before and after sustained-release beta-adrenergic blockade. | Drug: Metoprolol Succinate<br>* Once daily, oral, 12.5 mg to 200 mg, dose titrated to reduce heart rate by 20% or to less than 65 beats per minute.<br>* Other names: metoprolol XR;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Improvement in Sympathetic Cardiac Innervation as Measured by I-123 MIBG Heart - Mediastinum Ratio | 24 subjects had baseline I-123 MIBG imaging. No subject completed all aspects of the protocol. The study was closed due to unfavorable publication related to metoprolol treatment for hypertension. | january 2018 | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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hypertension, sympathetic nervous system