Characterization of Left Atrial Substrate by Comparison of Bipolar Voltage Maps With Standard Focal 4.5 mm Tip Electrode, 1 mm Ring Electrode, and Microelectrode Catheters Using InTEllaMap Orion and IntellaNav MIFI O

Study Overview
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Brief Summary
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This study is to investigate the correlation and to obtain the coefficient of correlation between the global and local bipolar signals (voltage maps) of the LA in sinus rhythm using a focal 4.5 mm irrigated-tip ablation catheter (in combination with microelectrodes), a ring-electrode circular mapping catheter and a microelectrode multipolar catheter in combination with the Rhythmia system.

Detailed Description
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Current hypothesis of the mechanism of atrial fibrillation (AF) is a combination of local firing mainly triggered from the pulmonary veins and atrial substrate due to atrial remodelling sustaining AF. Whereas for paroxysmal AF, pulmonary vein isolation (PVI) is still the mainstay of interventional treatment, a left atrial (LA) substrate-based ablation especially in patients with persistent or long-standing persistent AF may be reasonable to improve freedom from AF. In addition, even in patients with paroxysmal AF, substrate-based ablation strategies have been shown to improve outcome. Substrate characterization of the LA is currently performed using the focal ablation catheter with a 3.5mm irrigated tip catheter with a 2 mm interelectrode spacing, a circular (Lasso) or spider like diagnostic (Pentaray) catheter with 1 mm size of the ring electrodes and 2 mm to 4 mm interelectrode spacing. Consequently, the cut-off values to delineate healthy tissue from diseased substrate are defined based on these measures. Since the electrode size and distance between the electrodes determines the bipolar voltage amplitude and morphology (beside their orientation with regard to the propagation wavefront), differences in bipolar voltage values must be expected between different catheter types and especially for the novel micro-electrode catheters IntellaMap Orion and IntellaNav MIFI OI. With the knowledge of the relationship between the bipolar voltage maps created with the different catheter types, information/knowledge from one study obtained with a specific catheter can be transferred to patients treated with the other catheter types. This study is to investigate the correlation and to obtain the coefficient of correlation between the global and local bipolar signals (voltage maps) of the LA in sinus rhythm using a focal 4.5 mm irrigated-tip ablation catheter (in combination with microelectrodes), a ring-electrode circular mapping catheter and a microelectrode multipolar catheter in combination with the Rhythmia system.

Official Title
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Characterization of Left Atrial Substrate by Comparison of Bipolar Voltage Maps With Standard Focal 4.5 mm Tip Electrode, 1 mm Ring Electrode, and Microelectrode Catheters Using InTEllaMap Orion and IntellaNav MIFI O

Conditions
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Atrial Fibrillation (AF)

Intervention / Treatment
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* Diagnostic Test: multipolar mapping catheter
* Diagnostic Test: multielectrode circular catheter
* Diagnostic Test: irrigated ablation catheter


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Documented atrial fibrillation First or repeat catheter ablation Exclusion Criteria: Previous heart surgery (high probability for atypical atrial tachycardia and non PV triggers for AF) Congenital heart disease (corrected or uncorrected) Severe uncorrected valvular heart disease Not willing or qualified for Magnetic Resonance Imaging of the heart Unable to provide informed consent Pregnancy (Pregnancy test will be performed before study participation) Patients with pacemaker or intracardiac defibrillator implanted

Ages Eligible for Study
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Minimum Age: 18 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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Arms and Interventions

| Intervention/Treatment |
| --- |
|Diagnostic Test: multipolar mapping catheter|mapping of the left atrium will be performed in sinus rhythm using the IntellaMap Orion multipolar mapping catheter (Boston Scientific).|
|Diagnostic Test: multielectrode circular catheter|mapping of the left atrium will be performed using the multielectrode circular catheter (Lasso, spacing 2-6-2 mm, Biosense Webster)|
|Diagnostic Test: irrigated ablation catheter|mapping of the left atrium will be performed using the irrigated ablation catheter (IntellaNav Mifi OI)|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Global bipolar and unipolar signal measured in millivolt (mV) | Global bipolar and unipolar signal for the different types of catheters measured in mV | single time point assessment at baseline | 
| Local bipolar and unipolar signal measured in mV | Local bipolar and unipolar signal for the different types of catheters measured in mV | single time point assessment at baseline | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Global fibrosis content and distribution from LGE-MRI measured in [%]. | Global fibrosis content and distribution from LGE-MRI measured in [%]. | single time point assessment at baseline | 
| Local fibrosis content and distribution from Late-gadolinium enhanced Magnetic Resonance Imaging (LGE-MRI) measured in [%]. | Local fibrosis content and distribution from LGE-MRI measured in [%]. | single time point assessment at baseline | 
| Differences of bipolar voltage characteristics between nearfield and farfield signals: amplitude (mV) | Differences of bipolar voltage characteristics between nearfield and farfield signals: amplitude (mV) | single time point assessment at baseline | 
| Differences of bipolar voltage characteristics between nearfield and farfield signals: frequency in Hertz (Hz) | Differences of bipolar voltage characteristics between nearfield and farfield signals: frequency (Hz) | single time point assessment at baseline | 
| Differences of bipolar voltage characteristics between nearfield and farfield signals: Duration in milliseconds (ms) | Differences of bipolar voltage characteristics between nearfield and farfield signals: duration (ms) | single time point assessment at baseline | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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left atrial (LA) substrate-based ablation, focal ablation catheter, bipolar voltage amplitude, micro-electrode catheter, IntellaMap Orion, IntellaNav MIFI OI, bipolar voltage maps, irrigated-tip ablation catheter, ring-electrode circular mapping catheter, microelectrode multipolar catheter