# Surgical Treatment of Cardiac Arrhythmias

> **NIH NIH R01** · WASHINGTON UNIVERSITY · 2020 · $466,763

## Abstract

7. Project Summary/Abstract
The highest incidence of atrial fibrillation (AF) in patients referred for cardiac surgery is seen in patients with
mitral valve (MV) disease. Approximately one third of patients referred for MV surgery have AF. Two to 2.5
million Americans suffer from MV disease and this prevalence is expected to double in the next 20 years. The
worldwide burden of MV disease is even greater, and it is the most common underlying etiology of AF in the
developing world. The most common underlying pathology is mitral regurgitation (MR).The purpose of this
proposed project is to characterize the chronic structural, electrical, and mechanical remodeling of the atria in
chronic MR in order to optimize and improve the surgical treatment of patients with both MR and AF.
To realize this goal, our laboratory has created a novel model to look at left atrial volume overload that is
physiologically similar to MR and has the advantage of being reversible, obviating the confounding effects of
corrective surgery. A shunt is made between the left atrial appendage and the left ventricle (LV). We will also
use two novel non-invasive technologies: electrocardiographic imaging and late gadolinium enhanced MRI to
define the fibrotic substrates and the effect this has on atrial activation in patients with MR and AF. The
specific aims are: Specific Aim 1. Define the electrical and mechanical substrates for AF in our chronic canine
MR model by characterizing the detailed biatrial electrophysiology with the use of optical mapping, and
correlating our mapping data with the underlying structural changes identified both by late gadolinium-
enhanced MRI and histology. Specific Aim 2. Determine the degree and distribution of oxidative stress in the
atria in our canine MR model. Define if the oxidative stress is originating in tissue, phagocytes or from both
sources and then determine if the oxidative stress causes fibrosis by selectively inhibiting either one or both of
these pathways. Specific Aim 3. Define the electrophysiological remodeling in patients with MR by using both
electrocardiographic imaging (ECGI) and intraoperative mapping during normal sinus rhythm and AF. This
electrical remodeling will be correlated with the underlying fibrosis determined by late gadolinium enhanced
MRI. Successful completion of these aims will help define the underlying mechanisms for AF in MR.
Specifically, it will help identify patients with MR who are at greatest risk of developing AF and will explain
why some patients with severe MR develop AF and some do not develop AF.

## Key facts

- **NIH application ID:** 9845784
- **Project number:** 5R01HL032257-35
- **Recipient organization:** WASHINGTON UNIVERSITY
- **Principal Investigator:** RALPH J DAMIANO
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $466,763
- **Award type:** 5
- **Project period:** 1983-08-08 → 2022-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9845784

## Citation

> US National Institutes of Health, RePORTER application 9845784, Surgical Treatment of Cardiac Arrhythmias (5R01HL032257-35). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9845784. Licensed CC0.

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