This study is part of a research project in which new ultrasound-based techniques will be examined to improve clinical decision making for patients with aortic stenosis. These patients could develop increased amounts of myocardial fibrosis. This fibrosis is associated with the patients' prognosis. Fibrosis can be evaluated with magnetic resonance imaging (MRI), which unfortunately is quite expensive and not easily available. Ultrasound-based parameters will be developed for the assessment of the amounts of myocardial fibrosis, especially in the left ventricle. Then it will be examined whether these parameters can predict the patients magnitude of fibrosis and check for association with the patients prognosis. MRI will serve as a gold standard for quantification of myocardial fibrosis. The new echocardiographic techniques and parameters are expected to provide new insights in the interplay between aortic stenosis and left ventricular function, and to ultimately improve the care for patients with aortic stenosis.

The present study's objectives are:

• Quantify the level of myocardial fibrosis in mild, moderate, and severe aortic stenosis compared with a healthy population.
• Evaluate the patients outcome after one and three year of follow-up

Inclusion Criteria:

• Able to undergo protocolled investigations
• Patients: Mild, moderate or severe AS

Exclusion Criteria:

• Renal insufficiency
• Previously myocardial infarction (ECG, echocardiogram or hospital record)
• Severe valvular heart disease (except patients)
• Other cardiac disease known to cause myocardial fibrosis
• Severe hypertension
• Other medical conditions deterring protocolled investigation and follow-up
• Other medical conditions affecting 5-yrs prognosis (cancer, pulmonary disease)
• Severely reduced image-quality (echocardiography and MRI)

Analysis will be blinded