Organization of Excitation in People With Atrial Fibrillation

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00871390
Recruitment Status : Completed
First Posted : March 30, 2009
Last Update Posted : July 19, 2017
National Heart, Lung, and Blood Institute (NHLBI)
Information provided by (Responsible Party):
Omer Berenfeld, University of Michigan

Brief Summary:
Atrial fibrillation (AF) is a condition in which the upper chambers of the heart, the atria, undergo an irregular beating rhythm. Despite the fact that AF is the most common type of sustained cardiac rhythm disturbance the investigators still do not understand it entirely and its current therapies are only marginally effective. The overall goal of our project is to determine the organization and mechanisms of electrical activation patterns during AF in humans.

Condition or disease
Atrial Fibrillation

Detailed Description:
Experiments in animal hearts demonstrated that some cases of atrial fibrillation (AF) may be maintained by a small number of drivers in the form of self-sustained, reentrant, electrical impulses located in the posterior left atrium (LA) wall, near the pulmonary veins (PV/LA junction). In those experiments, the fastest rotors acted as the highest frequency drivers that maintained the overall activity. This resulted in a hierarchy of local excitation frequencies throughout both atria. More recently, clinical studies have confirmed the existence of a hierarchical organization in the rate of activation of different regions in the atria of patients with paroxysmal and chronic atrial fibrillation. However, the mechanisms underlying such a hierarchical distribution of frequencies in human AF has not been explored. Our project will try to demonstrate the general hypothesis that both local activation frequency and degree of regularity, while different in different parts of the atrium, are distributed non-randomly, with different patterns of distribution in paroxysmal versus chronic AF patients. We further surmise that such patterns are the result of interrupted propagation of impulses emanating from the drivers localized at the site of highest frequency and organization activity, with a gradual reduction of activation frequency as the distance from the driver increases. To test our hypotheses we will use a combination of clinical and numerical studies. For the clinical part we will gather patients data in a collaborative site at Rochester, NY. The data obtained in that site will be analyzed and interpreted at the Institute for Cardiovascular Research in SUNY Upstate Medical University. For the numerical part, simulations on computer models of AF will be performed solely in the Institute for Cardiovascular Research. Our Specific Aims are: 1. Characterize the frequency of activation during AF in patients after heart surgery and relate it to the presence of fibrosis. 2. In computer simulations, to study the mechanisms of initiation and maintenance of AF at the PV/LA junction using three different computer models with increasing anatomical complexity (the description of the computer simulations is available only in the grant application). Successful achievement of our specific aims should help us advance understanding of the mechanisms and manifestations of this complex arrhythmia and may help to directly improve the efficacy of pharmacological and ablative therapies of AF in patients.

Study Type : Observational
Actual Enrollment : 146 participants
Observational Model: Cohort
Time Perspective: Prospective
Official Title: Complex Electrograms in Atrial Fibrillation: Spatiotemporal Organization and Mechanistic Insights and Organization in Acute Atrial Fibrillation Post Open Heart Surgery
Study Start Date : September 2006
Actual Primary Completion Date : August 2011
Actual Study Completion Date : August 2011

Resource links provided by the National Library of Medicine

Biospecimen Retention:   None Retained

Information from the National Library of Medicine

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Ages Eligible for Study:   18 Years to 75 Years   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Sampling Method:   Non-Probability Sample
Study Population
Patients with paroxysmal and chronic atrial fibrilation (AF).

Inclusion Criteria:

  • Clinical indication for curative ablation of AF
  • Patients will be enrolled as they are referred for the ablation therapy or post open heart surgery

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its identifier (NCT number): NCT00871390

United States, Michigan
University of Michigan
Ann Arbor, Michigan, United States, 48109
United States, New York
SUNY Upstate Medical University
Syracuse, New York, United States, 13210
Sponsors and Collaborators
University of Michigan
National Heart, Lung, and Blood Institute (NHLBI)
Principal Investigator: Omer Berenfeld University of Michigan

Responsible Party: Omer Berenfeld, Associate Professor of Internal Medicine and Biomedical Engineering, University of Michigan Identifier: NCT00871390     History of Changes
Other Study ID Numbers: 628
P01HL039707 ( U.S. NIH Grant/Contract )
First Posted: March 30, 2009    Key Record Dates
Last Update Posted: July 19, 2017
Last Verified: July 2017

Keywords provided by Omer Berenfeld, University of Michigan:
Paroxysmal Atrial Fibrillation
Permanent/Persistent Atrial Fibrillation

Additional relevant MeSH terms:
Atrial Fibrillation
Arrhythmias, Cardiac
Heart Diseases
Cardiovascular Diseases
Pathologic Processes