The Maintenance of Human Atrial Fibrillation
| Status: | Completed |
|---|---|
| Conditions: | Atrial Fibrillation, Cardiology |
| Therapuetic Areas: | Cardiology / Vascular Diseases |
| Healthy: | No |
| Age Range: | 21 - Any |
| Updated: | 4/2/2016 |
| Start Date: | December 2010 |
| End Date: | June 2014 |
| Contact: | Sanjiv Narayan, MD, PhD |
| Email: | kcmills@ucsd.edu |
| Phone: | (858) 552-8585 |
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.
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.
This proposal will test the hypothesis that spatially localized sites maintain ongoing human
AF, so that ablation at these drivers may eliminate AF on long-term followup. The
investigators will study atrial fibrillation in patients undergoing ablation, to identify
regions that may be sustaining AF, then ablate at them.
The study design will be to identify sites that may be maintaining AF, using mapping of AF
prior to ablation. Once identified, these sites will be targeted for ablated using
traditional methods. This process will be repeated up to six times. The locations of these
sites will be recorded, and compared to traditional sites for AF ablation, including the
pulmonary veins and left atrial roof. They will also be studied for the presence of complex
fractionated electrograms and high dominant frequency.
Patients with persistent, long standing persistent, and paroxysmal AF will be included, and
patients will then be followed for 6-12 months.
AF, so that ablation at these drivers may eliminate AF on long-term followup. The
investigators will study atrial fibrillation in patients undergoing ablation, to identify
regions that may be sustaining AF, then ablate at them.
The study design will be to identify sites that may be maintaining AF, using mapping of AF
prior to ablation. Once identified, these sites will be targeted for ablated using
traditional methods. This process will be repeated up to six times. The locations of these
sites will be recorded, and compared to traditional sites for AF ablation, including the
pulmonary veins and left atrial roof. They will also be studied for the presence of complex
fractionated electrograms and high dominant frequency.
Patients with persistent, long standing persistent, and paroxysmal AF will be included, and
patients will then be followed for 6-12 months.
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
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