Autonomic Innervation and MIBG Imaging

Study Overview
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Brief Summary
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Patients with symptomatic atrial fibrillation (AF), a rapid beating of the upper heart chambers, can undergo catheter ablation to control or eliminate their rhythm disorder. The radiopharmceutical 123I-mIBG (Adreview™ GE Healthcare) has been introduced to visually identify cardiac innervation. This study will use non-invasive evaluation using MIBG imaging to study if we can predict baseline autonomic characteristics in patients with AF, as well as clinical outcome based on post ablation imaging

Detailed Description
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This is a single centre, interventional, Phase III trial using the radiopharmaceutical 123I-mIBG for imaging. In this pilot study, up to 7 eligible participants will undergo pre-ablation and post ablation nuclear imaging. The major objective of our study is to evaluate the relationship between non-invasive imaging of cardiac innervation with invasive mapping of atrial innervation as determined by High Frequency Stimulation (standard of care to physiologically document autonomic function). This will be followed by the clinical ablation procedure, as discussed by the cardiac electrophysiologist, consisting of pulmonary vein (PV) antral isolation, inclusive of regions of autonomic innervation, and sites showing complex fractionated atrial electrograms (CFAE) when clinically indicated. The secondary objective is to determine the relationship between catheter ablation of AF and non-invasive nuclear imaging of cardiac innervation.

Official Title
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Cardiac Mapping of Autonomic Atrial Innervation and Its Relation to MIBG Nuclear Imaging in Patients With Atrial Fibrillation

Conditions
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Atrial Fibrillation

Intervention / Treatment
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* Other: Iodine-123 Meta-iodobenzylguanidine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 18-80 years. Symptoms including one or more of the following: palpitations, shortness of breath, dizziness, presyncope or syncope, chest pain, tiredness or lack of energy. Failure of beta-blockers or at least one antiarrhythmic agent other than Amiodarone to prevent AF. In those patients who are not eligible to antiarrhythmic agents other than Amiodarone, patients may choose to undergo catheter ablation rather than starting Amiodarone. Paroxysmal (self-terminating AF within 7 days) or persistent AF (requiring an intervention to terminate or lasting more than 7 days). Exclusion Criteria: Intracardiac thrombus as determined by transesophageal echocardiography Class III or IV congestive heart failure Persistent AF duration of more than 3 years Myocardial infarction within the last 6 months Left atrial size of greater than 55 mm determined by 2D echocardiogram Inability to undergo a transesophageal echocardiogram or cardiac CT Inability to undergo D-SPECT™ imaging Inability to take Warfarin or the new oral anticoagulants Previously received 123I-mIBG or 131I-mIBG History or suspicion of significant allergic reaction or anaphylaxis to iodine or iodinated imaging agents Use of medications for non-cardiac medical conditions that are known to interfere with 123I-mIBG uptake and these medications cannot be safely withheld for at least 24 hours before study procedures Diagnosis of or signs or symptoms of a neurologic disease such as Parkinson's disease, multiple systems atrophy or Parkinsonian syndromes, or other diseases known to affect the sympathetic nervous system Pregnancy as determined by a pre-procedure pregnancy tests

Ages Eligible for Study
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Minimum Age: 18 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: Diagnostic
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Iodine-123 Meta-iodobenzylguanidine<br>123I-mIBG administration followed by nuclear imaging pre-ablation and post-ablation | Other: Iodine-123 Meta-iodobenzylguanidine<br>* A single injection of the 123I-mIBG will be given. Imaging will be done twice following injection: at 0120 minutes and 3-5 hours. The timing is dependent on the specific participant and imaging characteristics. The imaging is done for approximately 24 minutes at each time point.<br>* Other names: 123I-mIBG;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Concordance | The concordance of the 123I-mIBG visual images with the identification of autonomic sites as determined by high frequency stimulation (HFS). | 2 years | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Observation of effects | The effects of radiofrequency ablation of AF on cardiac innervation will be observed visually on 123l-mlBG images and clinically with participant follow up. | 2 years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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123I-mIBG, atrial fibrillation, atrial cardiac innervation, catheter ablation of atrial fibrillation, High Frequency Stimulation, ganglionated plexuses, nuclear imaging