Characterising the Stable and Dynamic Left Atrial Substrate in Atrial Fibrillation Using High Density Contact and Non-contact Mapping
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 31
- 试验地点
- 2
- 主要终点
- To Define the Normal Range of Voltage Amplitude
研究概览
简要总结
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.
详细描述
This is a prospective, non-randomised mechanistic study of 35 patients, including 5 control patients with normal atria and 30 patients with atrial fibrillation.
The 5 control patients will be undergoing an elective catheter ablation for another arrhythmia (likely supraventricular tachycardia (SVT)) involving a trans-septal puncture for left atrial access.
The 30 main study participants will only be patients who are already planning to undergo a catheter ablation procedure for atrial fibrillation. This will include 10 patients who are undergoing elective AcQMap guided procedures, in order to correlate non-contact propagation patterns with contact substrate mapping. These 10 patients will also undergo cardiac MRI imaging.
Study participants will be identified by medical staff in the outpatient clinic at the time of listing for catheter ablation, or by review of patients electronically listed for this procedure. If patients are in the clinic and give consent then a member of the research team may approach them at this stage. If identified by medical staff through listing for the procedure, they will be approached by telephone. An information leaflet will then be provided by post or email (if this has not been provided in clinic) with contact details for the research team. If willing to participate then formal screening and recruitment will take place at the time of attendance for standard pre-procedure assessment appointments or when attending for the elective procedure. Information must have been provided with sufficient time for the potential participant to fully consider involvement prior to formal recruitment and consent (generally expected to be at least 24 hours). It will be clear that participation or choosing not to participate has no impact on proceeding with their planned procedure. As the baseline assessments required involve purely a review of a participants medical history and measurement of height and weight, this will be combined with the screening/recruitment visit, and providing information has been provided sufficiently in advance then may be undertaken at the time of attending for the study procedure.
Study procedure:
研究设计
- 研究类型
- Interventional
- 分配方式
- Non Randomized
- 干预模型
- Parallel
- 主要目的
- Basic Science
- 盲法
- None
入排标准
- 年龄范围
- 18 Years 至 —（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Participant is willing and able to give informed consent for participation in the study.
- •Male or Female, aged 18 years or above.
- •Diagnosed with paroxysmal or persistent atrial fibrillation and planned for a catheter ablation procedure (AF ablation group only).
- •Undergoing elective left sided catheter ablation procedure involving a trans-septal approach (Control group only).
- •In the Investigator's opinion the participant is able and willing to comply with all trial requirements.
排除标准
- •Previous cardiac surgery.
- •Previous left atrial ablation (catheter or surgical).
- •Medical history including any of: atrial fibrillation, atrial flutter, hypertension, diabetes mellitus, chronic obstructive pulmonary disease, significant mitral valve disease (stenosis or regurgitation), pulmonary hypertension, obstructive sleep apnoea, ischaemic heart disease, cerebrovascular disease, peripheral vascular disease, structural heart disease (excluding known accessory pathway), congenital cardiac anomaly (excluding accessory pathway), previous left atrial ablation (catheter or surgical), cardiac surgery (control group only).
- •Contraindications to MR scanning (such as metallic or electronic objects implanted in your body or history of severe claustrophobia) (AcQMap guided ablation group).
- •Significantly impaired renal function (eGFR<30ml/min).
- •Female participant who is pregnant, lactating or planning pregnancy during the course of the trial.
- •Any other significant disease or disorder which, in the opinion of the Investigator, may either put the participants at risk because of participation in the trial, or may influence the result of the trial, or the participant's ability to participate in the trial.
- •Participants who have participated in another research trial involving an investigational medicinal product in the past 12 weeks. (Involvement in any other research trial is not a contraindication per se).
结局指标
主要结局
To Define the Normal Range of Voltage Amplitude
时间窗: During ablation procedure
Mean and distribution of left atrial voltage amplitude across the whole chamber and by segments with lower limit of normal defined as the upper 95% value within the segment with the lowest mean amplitude at long pacing cycle length.
次要结局
- Effect of Pacing Cycle Length on Electrogram Morphology(During ablation procedure)
- Effect of Pacing Cycle Length on Conduction Velocity(During ablation procedure)
- To Compare Electroanatomic Voltage Mapping (EAVM) Performed With a Bipolar Contact Force Guided Ablation Catheter to the Abbott HD Grid Using Orthogonal Wave Analysis in Sinus Rhythm.(During ablation procedure)
- To Evaluate the Distribution of Late Gadolinium Enhancement on Cardiac MRI Relative to Electrogram Amplitude Identified Using the HD Grid(During ablation procedure)
- To Evaluate the Distribution of Electrogram Morphologies Relative to Late Gadolinium Enhancement on Cardiac MRI(During ablation procedure)
- To Evaluate the Effect of Cycle Length on Conduction Velocities Relative to Distribution of Late Gadolinium Enhancement on Cardiac MRI(During ablation procedure)
研究者
Tim Betts MD MBChB FRCP
Primary Investigator
Oxford University Hospitals NHS Trust