A Mechanistic Exploratory Study of AF-induced Cardiac Dysfunction and Symptoms

  • End date
    Oct 23, 2024
  • participants needed
  • sponsor
    Barts & The London NHS Trust
Updated on 23 March 2022
ejection fraction
heart failure
holter monitor
stress echocardiography
cardiac mri
catheter ablation


Although the heart rhythm disorder Atrial Fibrillation (AF) affects 2% of the population, the impact it has on an effected individual can be highly variable. Some people are asymptomatic whilst others can experience debilitating symptoms or heart failure (HF)- weakness of the heart muscle. The reason why this variability exists in unknown and how AF actually drives HF is unclear. HF can also be caused by many other reasons and it can be difficult to identify those patients with HF caused by AF versus patients with AF but their HF is due to a different reason. This is important as it would help us to identify those patients most likely to improve their heart function after the treatment of AF and thus gain more from invasive treatments like AF catheter ablation; which is effective at restoring normal heart rhythm but has some risks attached.

The investigators suspect the characteristics of the AF, such as how irregularly it makes the heartbeat, can be used to predict who will respond better. Studies of heart cells in the lab as well as animal models have suggested this characteristic may be the cause of AF-induced heart muscle weakness and reduce cardiac output, making it a potential predictor that can be measured. Other potential predictors will be measured during pre-procedural scans and tests too. The investigators will also explore whether there are predictors of which patients gain the most symptomatic benefit and gain insight into why some people develop symptoms of AF, whereas others do not.

By studying the structural and functional sequelae of catheter ablation in patients with HF the investigators hope to better understand the relationship between the two diseases.

Condition Atrial Fibrillation, Heart Failure
Treatment Cardiac MRI, stress echocardiography, Holter monitoring, Patient questionnaires
Clinical Study IdentifierNCT04987723
SponsorBarts & The London NHS Trust
Last Modified on23 March 2022


Yes No Not Sure

Inclusion Criteria

Referred for first AFCA procedure by their responsible physician
Persistent AF captured on ECG but not in continuous AF for more than 3 years. (Persistent AF will be defined as any continuous episode lasting longer than 7 days or requiring intervention to restore sinus rhythm after this time.)
Participants must have either
Left Ventricular Ejection Fraction (LVEF) < 50% by echocardiogram during routine screening or within 12 months prior to enrolment day. The echo must have been performed >3 weeks after optimisation of HF and rate control therapies, otherwise repeat imaging will be performed after this has been achieved
NYHA functional status II-III at the enrolment visit
Left Ventricular Ejection Fraction (LVEF) >50% by echocardiogram during routine screening or within 12 months prior to enrolment day
modified European Heart Rhythm Association 2a-4

Exclusion Criteria

Previous left atrial ablation procedure or surgery
Contraindication to chronic anticoagulation therapy or heparin
Unable or unwilling to consent to investigation and follow-up requirements or inability to comply with planned study procedures
LA anteroposterior diameter ≥ 5.5 cm or indexed LA volume ≥ 50mL/m2 on echo
Recent (last 6 months) event that may impact LV function- myocardial infarction, coronary revascularization, pacemaker or cardiac resynchronization therapy
AF suspected to be due to a reversible cause (e.g. hyperthyroidism, recent surgery)
Acute coronary syndrome within 4 weeks as defined by ECG ST segment depression or prominent T-wave inversion and/or positive biomarkers of necrosis (e.g. troponin) in the absence of ST-segment elevation and in an appropriate clinical setting (chest discomfort or angina equivalent)
Cardiac surgery, angioplasty, or cerebrovascular accident within 4 weeks prior to enrolment
Life expectancy less than 1 year
Chronic kidney disease stage 4 or 5
Any of the below cardiac diagnoses
Hypertrophic obstructive cardiomyopathy
Severe valvular disease
Restrictive or constrictive cardiomyopathy, including known amyloidosis, sarcoidosis
Complex congenital heart disease
Constrictive pericarditis
Severe pulmonary hypertension (RVSP > 60 mmHg)
Non-cardiac pulmonary oedema
Active myocarditis
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