Assessment of Myocardial Tissue Damage in Aortic Stenosis

Aortic stenosis (AS) is the most common valve disease in the United States and most common
indication for valve replacement surgery. Anatomical and hemodynamic severity of AS is
insufficient for elucidating patients' prognosis. Therefore, the decision about the optimal
timing of surgical intervention remains critical. However, the changes in structure and
electrical activity of the cardiac muscle can be assessed by noninvasive imaging and
electrocardiography (ECG). Degenerative myocardial changes characterized by fibrosis or
collagen deposits are frequently observed in AS patients and have a negative impact on
patient outcomes. In this project, our objective is to determine whether echocardiographic
image analysis of integrated backscatter (IB), which can express changes in myocardial
tissue composition (amount of fibrosis) based on its ultrasound reflectivity, global left
ventricular (LV) load as measured by Zva, and ECG analysis of the duration of the QRS
interval have a role in risk stratification for AS patients and to apply those methods to
identify which patients would benefit from surgical intervention.

The investigators hypothesize that 1) the severity of myocardial damage can discriminate the
prognosis in patients with AS, and 2) IB, Zva, and QRS interval can be diagnostic measures
of the severity of myocardial damage. The investigators will measure the severity of
myocardial fibrosis using MRI (reference) in 50 patients and will test the diagnostic
significance of IB (testing method). Zva, QRS duration, and conventional echocardiographic
measures will also be tested for diagnosing severity of myocardial fibrosis.