Catheter Contact Force and Electrograms

Study Overview
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Brief Summary
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Until recently, there was no way of telling how firmly the tip of the catheter was in contact with the heart and how this contact was orientated. The electrical signals measured through the catheters, known as electrograms, are used to guide the sites and duration of ablation, but the effect of catheter contact and orientation on these signals in human heart muscle that is fibrillating is not known. New catheters have now been developed which can measure the force of contact at their tip: using these, the investigators will examine how contact force affects the electrical behaviour of heart muscle tissue in atrial fibrillation. The effect the force of contact has on the electrogram recorded will also be investigated. In so doing we hope to gain a better understanding of the relationship between tissue contact and the electrograms we measure and in so doing improve the safety and effectiveness of ablation procedures. Hypothesis: Catheter contact force and orientation have a significant impact on the characteristics of bipolar electrograms in the fibrillating human atrium.

Official Title
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Relationship Between Catheter Contact Force and Electrogram Characteristics in Fibrillating Human Atrial Myocardium

Conditions
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Atrial Fibrillation

Intervention / Treatment
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* Device: THERMOCOOL® SMARTTOUCH™ Catheter (including Surround Flow)


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Persistent or paroxysmal atrial fibrillation Listed for ablation of atrial fibrillation on clinical grounds Exclusion Criteria: Contraindication to catheter ablation Contraindication to anticoagulation Contraindication to TOE

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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Design Details

Primary Purpose: Diagnostic
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Constant Catheter Contact Force<br>No alteration of catheter contact force during recording period | Device: THERMOCOOL® SMARTTOUCH™ Catheter (including Surround Flow)<br>* Variable contact force as measured at the catheter tip within the left atrium<br>|
| Experimental: Variable catheter contact force<br>change in contact force from low to high after 30seconds of recording. | Device: THERMOCOOL® SMARTTOUCH™ Catheter (including Surround Flow)<br>* Variable contact force as measured at the catheter tip within the left atrium<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Electrogram characteristics | Effect of changes in contact force and orientation on: slew rate, local mean cycle length, electrogram complexity and fractionation index, dominant frequency, organisation index, CFAE grade, interval confidence level, shortest complex interval and average complex interval | Baseline and 30 seconds | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Electrogram amplitude |  | Baseline and 30 seconds | 
| Electrogram responses to ablation | Slew rate, local mean cycle length, electrogram complexity and fractionation index, dominant frequency, organisation index, CFAE grade, interval confidence level, shortest complex interval and average complex interval, amplitude change, AF cycle length, catheter impedance. | Baseline and 30 seconds | 
| Ablation Power (Watts) | The interaction between catheter contact force and orientation and the power attained during power limited ablation | Baseline and 30 seconds | 
| Electrogram Contact Mapping | Use of contact catheters - Constellation and/or PentaRay Catheter to record fibrillatory electrograms and identify areas of interest | During Study | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Atrial Fibrillation, Electrogram, Ablation, Contact Force