EP Study of Patients Who Have Received Left Atrial Ablation Using High Intensity Focused Ultrasound

NCT ID: NCT01769287

Last Updated: 2017-09-19

Basic Information

• Recruitment Status: COMPLETED
• Total Enrollment: 20 participants
• Study Classification: OBSERVATIONAL
• Study Start Date: 2013-01-31
• Study Completion Date: 2013-09-30

Brief Summary

The purpose of this study is to check if at 1 year after surgical ablation the electrical impulses that cause atrial fibrillation (AF) are still blocked from being able to get into the heart.

Hypothesis Conduction block and ganglionic destruction are required for freedom from AF.

Detailed Description

Atrial fibrillation (AF) is an increasing common disease. It ranges from being asymptomatic to a highly disabling condition with a severe impact on quality of life. It is termed paroxysmal (PAF) when an episode lasts less than 7 days, persistent (PerAF) when it lasts more than 7 days and needs intervention and permanent (PermAF) when it is accepted as the long term rhythm. Treatment is based on symptom control and the prevention of complications such as stroke. When an attempt is made to restore normal sinus rhythm (NSR), this is termed 'rhythm control'.

Treatments for rhythm control of AF can be broadly divided into pharmacological and ablative. Ablative techniques1 are typically performed percutaneously using catheter-based technology (minimally invasive), though some surgical techniques also exist. They work on the principle that performing a series of 'burns' (scar) in appropriate places can prevent abnormal electrical signals forming and propagating within the heart.

The problem of atrial fibrillation is vast. Prevalence ranges from 0.2% in the 45-54 age group, rising to 8% in the over 75s. Though the majority of patients can be satisfactorily treated medically, in a not insignificant portion, the drugs are either poorly tolerated or are ineffective. For these patients, the United Kingdom (UK) NICE guidelines recommend consideration of an ablation procedure. In Derriford hospital alone we see approximately 14 patients suitable for AF ablation in a typical month.

The electrophysiological consequences of ablation are unclear. It is not known whether complete bidirectional electrical block across the ablation lines isolating the pulmonary antral region from the rest of the left atrium is a prerequisite for long-term cure of Atrial Fibrillation (AF). Studies in canine models of atrial fibrillation have suggested that incomplete lines of block can be as effective in reducing AF burden as complete lines, however the limited number of follow up studies in humans that have assessed both patients with recurrent AF and also asymptomatic patients who appear to have been cured by catheter ablation have suggested that complete electrical isolation of the pulmonary veins is necessary for a cure. Advocates for ablation without assessing electrical block argue success rates in humans are similar whether circumferential electrical isolation of the pulmonary veins is achieved or not. Assessing freedom from AF and correlating it with the presence or absence of complete bidirectional electrical block, intra-operatively and at post one-year follow-up, will allow a further understanding of the mechanisms determining the success or failure of AF ablation therapies. This will be very important in knowing how to treat patients in whom AF still occurs and will guide the approach to subsequent interventions.

Though there is a small risk involved in this study, the question it addresses will have a significant impact on the development of future AF ablation techniques. Within this group, over 300 separate ablation procedures have been performed with no deaths or significant complications. Previous groups have published trans-septal observational studies in humans demonstrating that previous ethics committees have appreciated the importance of such work. The 2012 Heart Rhythm Society (HRS)/European Heart Rhythm Association (EHRA)/European Cardiac Arrhythmia Society (ECAS) consensus statement on catheter and surgical ablation for AF has recently highlighted the need for novel trial designs demonstrating 'durability of pulmonary vein isolation' with a repeat diagnostic electrophysiological study.

This trial will therefore increase our understanding of the electrophysiological properties associated with successful ablation and how Atrial Fibrillation ablation and the HIFU procedure work.

Conditions

Atrial Fibrillation

Study Design

• Observational Model Type: COHORT
• Study Time Perspective: PROSPECTIVE

Study Groups

Surgical operation

The study aims to recruit a total of 20 patients, 10 of whom have AF and 10 who do not.

No interventions assigned to this group

Eligibility Criteria

Inclusion Criteria

• Patients who have undergone an Epicor HIFU ablation >12 months ago
• Patients having the ability to fully comply with the study requirements
• Patients who have given written fully informed consent to participate in the study

Exclusion Criteria

• Patients will be excluded from the study if they meet any of the following criteria:

• Patients who are unable to give full informed consent for the present sub-study.

• Minimum Eligible Age: 18 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Abbott Medical Devices

INDUSTRY

Sponsor Role: collaborator

University Hospital Plymouth NHS Trust

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Malcolm Dalrymple-Hay, MB BS, PhD

Role: PRINCIPAL_INVESTIGATOR

University Hospital Plymouth NHS Trust

Locations

Plymouth Hosptals NHS Trust

Plymouth, Devon, United Kingdom

Countries

United Kingdom

Other Identifiers

AF08004AF

Identifier Type: -

Identifier Source: org_study_id