Atrial Fibrillation | The Maintenance of Human Atrial Fibrillation

Atrial Fibrillation research study

What is the primary objective of this study?

Atrial fibrillation (AF) is the most prevalent heart rhythm disorder in the United States, affecting 2.5 million individuals in whom it may cause stroke, palpitations, heart failure, and even death. Unfortunately, therapy for AF is limited. Anti-arrhythmic or rate-controlling drugs are poorly tolerated, with frequent side effects and do not reduce stroke risk. Ablation is an emerging, minimally invasive therapy that has attracted considerable attention because it may eliminate AF. Unfortunately, AF ablation is technically challenging, with a success of only 50-70% (versus >90% for other arrhythmias) and serious risks. A major cause of these limitations is that the mechanisms for human AF are not known and thus ablation cannot be directed to them. As a result, AF ablation is empiric and results in extensive destruction of the atrium. This project will perform research to better understand AF and determine if abnormal activity in small regions or more widespread regions of the heart cause AF. By performing these studies in patients during clinical procedures, this project may lead to a paradigm shift in the understanding and treatment of AF.

Who is eligible to participate?

INCLUSION CRITERIA for STUDY SUBJECTS: - patients undergoing electrophysiology study (EPS) for ablation of (a) paroxysmal AF (non-rheumatic) whose AF episodes self-terminate in < 7 days, or (b) persistent AF (non-rheumatic) whose AF episodes last >or= 7 days but terminate with DC cardioversion or anti-arrhythmic drugs and do not recur within 24 hours. - AF patients must have failed >or= 1 anti-arrhythmic drug INCLUSION CRITERIA for ALL SUBJECTS: - will have a full evaluation focusing on diabetes mellitus, hypertension, coronary disease, left ventricular ejection fraction (LVEF). We will document whether AF relates to times of vagal activity (meals or sleep) or exercise. We will record the use of drugs affecting the renin-aldosterone-angiotensin system (RAAS) and statins, that may protect against atrial fibrosis and AF. We will document serum potassium level, since slight elevations slow CV in vitro. We will record 12-lead ECG and echocardiography for left atrial diameter, and stress test and/or coronary angiography if indicated. - will have event monitor recordings with daily transmissions for at least one week to document AF burden (study subjects) or exclude AF (control subjects). - must have with-held amiodarone for > 30 days and other anti-arrhythmic drugs for > 5 half-lives. EXCLUSION CRITERIA FOR ALL SUBJECTS: - active coronary ischemia in the past year, since the protocol uses isoproterenol - rheumatic valve disease, that leads to distinct AF and increases thromboembolic risk - prior ablation or cardiac surgery, that alters atrial electrophysiology - LA clot or dense contrast on TEE - deranged serum electrolytes, and K+ outside 4.0-5.0 mmol/l - left atrial diameter > 60 mm - LVEF < 40% or New York Heart Association heart failure > Class II, to exclude distinct, heart-failure related remodeling - thrombotic disease, venous filters, transient ischemic attack or cerebrovascular accident, to minimize additional risk - pregnancy, to minimize fluoroscopy. As part of routine clinical care, all female patients of childbearing age receive a ß-HCG pregnancy test. Any who test positive will not be included in the research study - inability or unwillingness to provide informed consent

Which medical condition, disease, disorder, syndrome, illness, or injury is researched?

Atrial Fibrillation

Arrhythmias, Cardiac

Study Interventions

Interventions can include giving participants drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available or noninvasive approaches such as surveys, education, and interviews.

Study Arms

Research studies and clinical trials typically have two or more research arms. An arm is a group of people who receive the same treatment in the study.

InterventionPatients with persistent, long standing persistent and paroxysmal AF, who will receive ablation at sites that potentially maintain human AF.

ControlPatients with persistent, long standing persistent and paroxysmal AF, who receive conventional ablation as determined by the operator at each site, and based upon Heart Rhythm Society guidelines.

Study Status

Unknown status

Start Date: December 2010

Completed Date: June 2014


Type: Observational


Primary Outcome: recurrence of atrial fibrillation

Secondary Outcome:

Study sponsors, principal investigator, and references

Principal Investigator: Sanjiv Narayan, MD, PhD

Lead Sponsor: University of California, San Diego

Collaborator: National Institutes of Health (NIH)

More information:

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