Characterising the Stable and Dynamic Left Atrial Substrate in Atrial Fibrillation

Sponsor
Oxford University Hospitals NHS Trust
Study ID
NCT04229472
Status
Completed

Conditions

Eligibility Criteria

Sex
ALL
Age
18 Years - N/A
Healthy Volunteers
Accepted

Interventions

  • High density electrophysiological mapping — DIAGNOSTIC_TEST
    Recording of electrophysiological data using a high density contact catheter during pacing at the time of catheter ablation for atrial fibrillation.
  • Cardiac Magnetic Resonance Imaging — DIAGNOSTIC_TEST
    Late gadolinium enhance cardiac magnetic resonance imaging (in AcQMap group only)

Study Details

Atrial fibrillation (AF) is the most common sustained arrhythmia, with increasing prevalence associated with an ageing population. Management is challenging, and invasive catheter ablation procedures are increasingly used in those with symptoms refractory to drug therapy. Unfortunately, success rates from this procedure can be limited. This is partly due to limitations in understanding of the mechanisms involved in arrhythmia propagation. There is much interest in the role of structural changes within the muscle of the left atrium resulting in scaring (known as fibrosis). This has been identified on MRI studies and invasive electroanatomical mapping using voltage amplitude of recorded signals as a surrogate measure of tissue properties. This however is affected by the technology used, as it does not routinely incorporate the effect of heart rate on conduction properties. Furthermore, although this aims to identify regions of structural changes, it does not identify more dynamic patterns of conduction seen during AF. This study aims to use a high density mapping catheter (Abbott Advisa HD grid (SE)), which employs a novel algorithm to minimise the effect of wavefront direction on the size of electrical signals. Electroanatomical mapping of the left atrium in patients with atrial fibrillation will be conducted whilst pacing at long and short cycle lengths to assess the effect of pacing rate on conduction properties, assessed using signal morphology and conduction velocity. The same procedure will also be carried out in 5 control patients to allow comparison with normal atria. Two subgroups will also analysed. In the first the aim is to compare the use of the HD grid catheter to a bipolar ablation catheter in carrying out electroanatomical mapping. In the second, to correlate electrical signals obtained with propagation patterns identified using the AcQMap non-contact mapping system and atrial properties identified on cardiac MRI.

Key Dates

Start date
Dec 7, 2020
Status verified
Jul 2025
Primary completion
Nov 2, 2023
Completion
Nov 2, 2023

Study Design

Enrollment
31 participants (actual)
Allocation
NON_RANDOMIZED
Intervention model
PARALLEL
Primary purpose
BASIC_SCIENCE

Arms

  • Experimental: Normal subject control group
    High density mapping of left atrial voltages in patients with supraventricular tachycardia
  • Experimental: Atrial fibrillation group
    High density mapping of left atrial voltages
  • Experimental: AcQMap atrial fibrillation group
    High density mapping of left atrial voltages and AcQMap propagation patterns alongside cardiac MRI

Primary Outcome Measure

To Define the Normal Range of Voltage Amplitude [ Time Frame: During ablation procedure ]

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