Attention should be directed to the trend in recent INR determinations. Prosthesis patient mismatch and functional stenosis of a repaired native valve are also to be considered in the evaluation of patients with HF symptoms. Repeat noninvasive assessment begins with trans- thoracic echocardiography, comparison with the index postoperative study when available, and the use of other modalities as dictated by the clinical context and preliminary findings. 3. TTE is the preferred approach for initial assessment of suspected prosthetic valve dysfunction because it allows for measurement of transvalvular velocity, gradient, and valve area. TTE also allows quantita- tion of LV volumes and LVEF, an estimate of pulmo- nary artery systolic pressure, and evaluation of right heart function. However, the LA side of a prosthetic mitral valve is obscured by acoustic shadowing from the TTE approach, resulting in reduced sensi- tivity for detection of prosthetic MR and prosthetic mitral valve thrombus, pannus, or vegetation. TEE provides superior imaging of the LA side of the mitral prosthesis and is accurate for diagnosis of prosthetic mitral valve dysfunction.5,6 Both TTE and TEE are also needed for patients with prosthetic aortic valves in whom the posterior aspect of the valve is shadowed on the TTE approach and the anterior aspect of the valve is shadowed on the TEE has superior sensitivity for the detection of vegetations and abscess formation in patients with suspected prosthetic valve (or annu- loplasty ring) endocarditis. With mechanical valve obstruction, fluoroscopy or CT imaging can also be helpful for detection of reduced motion caused by pannus ingrowth or thrombus. 4. 