The standard of treatment for aortic stenosis is an operation, aortic valve repair (AVR), where a mechanical or biological valve replaces the old one. The operation involves a substantial risk of postoperative mortality, and is therefore delayed until the patient develops symptoms such as shortness of breath, chest pains or syncope. For most patients AVR causes significant symptom reduction and reduced mortality. Recent studies have indicated that patient with severe MF, which may account for up to one third of the patients treated, have little or no symptom improvement and an increased mortality after AVR. This raises concern that their LV is so severely fibrotic that it is beyond repair. These patients may not benefit from an operation, or should possibly have had AVR performed at an earlier stage of the disease.