An observational study in Atrial Fibrillation, sponsored by University of Utah. Completed. Open to participants aged 18 Years to 89 Years. Per ClinicalTrials.gov, last updated 2012-02-13.
Sponsored by University of Utah · Observational
The purpose of this study is to evaluate the impact of pre-ablation fibrosis on scar formation in the left atrium of the heart. This will be assessed by delayed enhancement magnetic resonance imaging and will be looked at in patients who have undergone successful open irrigated cooled-tipped radio-frequency ablation of paroxysmal atrial fibrillation. Follow-up after ablation will be for 12 months.
Atrial fibrillation (AF) is an electrophysiological condition characterized by disorganized electrical activity that involves the entire atria. AF manifests initially as paroxysms of arrhythmia that later progress into persistent and permanent forms. It is a progressive disease associated with structural, electrical and contractile changes in the left atrium (LA). A major determinant of the progression of AF is structural remodeling or fibrosis that occurs in the left atrium. A more extensively remodeled atrium presents the substrate needed for the arrhythmia to persist. Structural remodeling is also a major determinant for success of rhythm control strategies in AF. While catheter ablation has reproducibly been shown to be superior to anti-arrhythmic drug (AAD) therapy for rhythm control in AF, the success of this procedure is significantly affected by the extent of structural remodeling present at the time of catheter ablation.
Delayed-Enhancement Magnetic Resonance Imaging (DE-MRI) has been demonstrated to be a very effective modality in identifying fibrotic and scarred cardiac tissue with excellent correlation to electro-anatomical mapping. This is related to the characteristics of Gadolinium, an extracellular contrast agent that is very effective in identifying regions of fibrotic non-viable myocardium. DE-MRI technology can be a very powerful, non-invasive method, of identifying the extent and the distribution of structural remodeling or fibrosis associated with AF. Specific image acquisition sequences have allowed for reproducible identification of high pixel intensity regions within the 2-dimensional images of the atrial wall. 3-Dimensional reconstruction of the entire left atrium then provides a quantification of the overall volume occupied by these hyper-enhanced regions relative to the entire left atrial wall volume. Used prior to catheter ablation, DE-MRI can therefore identify regions of significant structural remodeling or fibrosis. The same technology has also been shown to be very useful in examining the amount and distribution of ablation-induced scarring.
Catheter ablation has emerged as an effective interventional therapeutic modality for AF patients. Current ablation techniques, including pulmonary vein antrum isolation (PVAI), use radiofrequency (RF) energy to induce thermal damage to the LA substrate in an attempt to electrically disconnect and isolate arrhythmogenic foci originating from the pulmonary veins (PVs). Multiple catheter technologies for RF have been developed. Catheters may be either cooled or not. Cooling allows for higher and deeper energy delivery with larger lesion formation. Open irrigation cooled-tip RF ablation of AF is associated with less impedance rise, microbubble formation, and esophageal injury when compared with traditional non-cooled ablation catheters. It is also associated with shorter RF delivery time, fluoroscopy, and procedural time.
Understanding the temporal sequence of events of LA structural remodeling (preceding AF ablation) to scar formation (following AF ablation) can prove valuable in determining whether certain patients are more susceptible to recovery of electrical conduction and recurrence of AF. DE-MRI recently has been introduced as a means to visualize this RF-induced scarring post-ablation. These scans can be reconstructed into three-dimensional (3D) recreations of the LA allowing for further analysis and quantification of the LA scar formation following RF ablation.
Objectives:
Primary Objective
Secondary Objectives
3,870 studies on the registry are indexed under Atrial Fibrillation; 924 are open to participants now.
This study's enrollment of 40 is below the median of 300 across 1,363 observational studies indexed under Atrial Fibrillation.
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Forty patients ages 18-89 years, who have had an open irrigation cooled-tipped RF ablation procedure for PAF. Patients must participate in 3-, 6-, and 12-months follow-up post ablation. PAF is defined by >2 documented episodes of AF that terminate spontaneously within 7 days. AF has to be documented by means of electrocardiography, holter monitor, loop recorder, or echocardiography.
Exclusion Criteria:
Those individuals who had an ablation using open irrigation cooled-tip RF ablation.
Left Atrial (LA) Remodeling Pre-ablation
Utah staging for fibrosis (I - \<=5%, II - 5.01%-20.0%, III - 20.01%-35% and IV - \>=35.01%)
Time frame: Once pre-ablation
Patients were recruited based on chart review
| Milestone | Open Irrigation |
|---|---|
| Started | 40 |
| Completed | 40 |
| Not completed | 0 |
Utah staging for fibrosis (I - \<=5%, II - 5.01%-20.0%, III - 20.01%-35% and IV - \>=35.01%)
| participants | Open Irrigation |
|---|---|
| Utah stage 1 | 2 |
| Utah stage 2 | 31 |
| Utah stage 3 | 7 |
| Utah stage 4 | 0 |
Collected over This was a retrospective, observational study. Patients were enrolled using chart review. Hence, it did not include collection of adverse events.. Non-serious events are listed at a 0% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Open Irrigation | — | — | — |
| Age, Categorical(Participants) | Open Irrigation |
|---|---|
| <=18 years | 0 |
| Between 18 and 65 years | 14 |
| >=65 years | 26 |
| Age Continuous(years) | Open Irrigation |
|---|---|
| Mean | 65.2 ± 12.3 |
| Sex: Female, Male(Participants) | Open Irrigation |
|---|---|
| Female | 21 |
| Male | 19 |
No study locations are listed for this record.
This study is completed, as verified in Feb 2012. You cannot join it, but the record below documents what was studied.
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