Inflammatory and Endothelial Function Response, and Arrhythmia Recurrence Following Catheter Ablation for Atrial Fibrillation

Post-ablation Inflammatory Response and Endothelial Function in the Development of Early Recurrence of Atrial Tachyarrhythmia After Pulmonary Vein Isolation; Implications for Pulmonary Vein Reconnection and Freedom From Atrial Fibrillation

Current international guidelines recommend a three-month blanking period after pulmonary vein isolation (PVI) for atrial fibrillation (AF). Early recurrence of atrial tachyarrhythmia (ERAT; comprising of AF, left atrial tachycardia and atrial flutter) is common, occurring in up to 65% of patients, but in the first month is generally thought not to predict long-term AF recurrence, and re-intervention is not recommended. Suggested causes for ERAT include inflammation and arrhythmogenic structural changes caused by ablation lesions. Early, purely inflammatory ERAT would not lead to late AF recurrence as pulmonary vein reconnection is established as the main factor associated with long-term recurrence in paroxysmal AF. Previous studies have shown ERAT in the second to third month (rather than first month) to be a stronger predictor of late AF recurrence, due to presumed reduction in the contribution of the acute inflammatory response after this. Biochemical data have shown that the post-ablation inflammatory phase is usually limited to the first month after both radiofrequency (RF) and cryoballoon (CB) ablation, though inflammatory markers have been shown to be less elevated following CB PVI. Histologically, lesions formed by the two modalities differ significantly. RF lesions are characterised by irregular boundaries and significant disruption to the endothelium, exposing the sub-endothelial layer and resulting in significant and sustained platelet activation, changes which can last for many months. CB lesions on the other hand, are observed as well demarcated and homogenous within one week, with reduced thrombogenicity, which may lead to reduced inflammation. ERAT following CB ablation cannot be accurately predicted by inflammatory response and it is postulated that endothelial function may play a role in the development of ERAT in such patients. Some studies have shown reduced recurrence rate and re-hospitalisation amongst the CB population, including the FIRE and ICE trial, potentially resulting in a better patient experience with CB and the possibility of a shorter blanking period. Post-ablation inflammatory response is more predictive of ERAT following RF than CB PVI, and the latter is considered to be associated with less inflammation. There is however, a paucity of data evaluating endothelial function post-AF ablation and its correlation with ERAT or late recurrences of arrhythmia. Given that earlier re-intervention in patients with ERAT in the third month of the blanking period can result in greater outcomes with respect to late recurrence of AF, if it can be demonstrated that endothelial function testing in the first few months post-CB PVI can be predictive of later ERAT, then shortening the blanking period following CB PVI and performing repeat ablation to control troublesome later ERAT may reduce overall patient morbidity and re-hospitalisation.

The purpose of this novel pilot study is to examine the relationship between the post-ablation inflammatory response, endothelial function and timing and frequency of ERAT for patients undergoing RF and CB PVI for paroxysmal or short-lived persistent (less than 6 months' duration) AF. If the initial data provides hypothesis generating information, the aim would be to perform the study on a larger basis with higher statistical power to determine whether early post-ablation endothelial function testing can predict recurrences and identify those suitable for earlier re-intervention.

Study Overview

• Status: Withdrawn
• Conditions: Paroxysmal Atrial Fibrillation; Persistent Atrial Fibrillation
• Intervention / Treatment: Device: Radiofrequency ablation; Device: Cryoballoon ablation

• Study Type: Interventional
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Gwilym Morris, BM BCh MRCP PhD; Phone Number: 0161 901 0116; Email: gwilym.morris@manchester.ac.uk

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 16 years to 63 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No

Description

Inclusion criteria

• Age 18-75 years
• Paroxysmal AF or persistent AF of less than 6 months' duration
• Structurally normal heart on transthoracic echocardiogram other than mild left atrial dilatation (<34ml/m2, indexed to body surface area)
• Due to undergo pulmonary vein isolation on clinical grounds

Exclusion criteria

• Known genetic/inherited disorder that predisposes to atrial fibrillation, or Brugada syndrome
• Metabolic syndrome as defined by National Cholesterol Education Program (NCEP) Adult Treatment Panel III (ATP III) criteria
• Obesity (BMI>40)
• Inability or unwillingness to receive oral anticoagulation with a vitamin K antagonist (VKA) or non-VKA oral anticoagulant (NOAC)
• Known atrial flutter
• Ischaemic heart disease documented by coronary or CT angiography, or confirmed history of myocardial infarction
• Current stage II or III hypertension (diastolic BP >100mmHg, systolic BP>160mmHg) confirmed on serial readings or ambulatory monitoring
• Diabetes mellitus other than diet controlled
• Previous catheter or surgical ablation procedure for AF
• Unwillingness or inability to complete the required follow-up arrangements
• Persistent AF > 6 months' duration or permanent AF
• Prior prosthetic heart valve replacement or structural cardiac abnormality including moderate or severe heart valve disease
• Moderate or severe left atrial dilatation
• Known infiltrative cardiomyopathy
• Known left ventricular systolic dysfunction (ejection fraction <45%)
• Pregnancy
• Co-morbidities known to be associated with an inflammatory response (eg. Rheumatoid arthritis)
• Unexplained baseline elevation of ESR or CRP above the normal lab reference ranges
• Additional ablation lesions beyond pulmonary vein isolation

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Radiofrequency ablation; These patients will receive ablation by radiofrequency catheter, guided by of 3-dimensional electro-anatomic mapping technology	Device: Radiofrequency ablation; Ablation aimed at performing pulmonary vein isolation for atrial fibrillation using radiofrequency catheter (heat therapy)
Active Comparator: Cryoballoon ablation; These patients will receive ablation by cryoballoon catheter, guided by X-ray fluoroscopy	Device: Cryoballoon ablation; Ablation aimed at performing pulmonary vein isolation for atrial fibrillation using cryoballoon catheter (cold therapy)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Incidence of recurrence of atrial arrhythmia in the 3 months following ablation	Whether patients have experienced a recurrence of atrial arrhythmia (AF, left atrial flutter or left atrial tachycardia) in the 3 months following their ablation	3 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Rate and degree of rise of inflammatory markers in the 3 months following ablation	Inflammatory blood markers such as CRP	3 months
Degree of endothelial dysfunction in the 3 months following ablation (EndoPAT testing)	Endothelial function measured using the EndoPAT technology	3 months

Collaborators and Investigators

• Sponsor: Karan Saraf
• Collaborators: University of Manchester
• Investigators: Principal Investigator: Gwilym Morris, BM BCh MRCP PhD, The University of Manchester

Study record dates

Study Major Dates

• Study Start (Estimated): January 30, 2023
• Primary Completion (Estimated): January 30, 2024
• Study Completion (Estimated): June 1, 2024

Study Registration Dates

• First Submitted: January 23, 2020
• First Submitted That Met QC Criteria: February 11, 2020
• First Posted (Actual): February 17, 2020

Study Record Updates

• Last Update Posted (Actual): November 1, 2023
• Last Update Submitted That Met QC Criteria: October 29, 2023
• Last Verified: October 1, 2023

More Information

Terms related to this study

• Keywords: atrial fibrillation; inflammation; recurrence; ablation; endothelial function; cryoballoon; radiofrequency
• Additional Relevant MeSH Terms: Pathologic Processes; Heart Diseases; Cardiovascular Diseases; Disease Attributes; Arrhythmias, Cardiac; Atrial Fibrillation; Recurrence
• Other Study ID Numbers: 262517

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No