Clinical trial NCT00871390: Organization of Excitation in People With Atrial Fibrillation
Official title: Complex Electrograms in Atrial Fibrillation: Spatiotemporal Organization and Mechanistic Insights and Organization in Acute Atrial Fibrillation Post Open Heart Surgery
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Atrial Fibrillation
Keywords: Paroxysmal Atrial Fibrillation
Permanent/Persistent Atrial Fibrillation
Lead sponsor: University of Michigan
Sponsor class: OTHER
Collaborators: name: National Heart, Lung, and Blood Institute (NHLBI)
First posted: 2009-03-30
Enrollment: 146
Sex: ALL
Minimum age (years): 18
Maximum age (years): 75
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: no
Observational model: COHORT
Time perspective: PROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: Patients with paroxysmal and chronic atrial fibrilation (AF).

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.

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.

Eligibility criteria: 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

Primary outcomes:
Secondary outcomes:
Other outcomes:
Locations:
city: Ann Arbor
country: United States
facility: University of Michigan
state: Michigan
city: Syracuse
country: United States
facility: SUNY Upstate Medical University
state: New York
Study officials:
affiliation: University of Michigan
name: Omer Berenfeld
role: PRINCIPAL_INVESTIGATOR
References: