TEE offers excellent visualization of the mitral valve and LA and is an alternative approach to assessment of rheumatic MS in patients whose TTE images are technically limited. In patients being considered for PMBC, a TEE can rule out LA cavity and appendage thrombi.4 6 TEE also is use- ful for evaluation of MR severity in patients being considered for PMBC because shadowing of the LA on TTE may result in underestimation of MR severity. MR that is more than mild is a contrain- dication to PMBC. 6.2.1.2. Diagnostic Testing: Changing Signs or Symptoms Patients with an established diagnosis of rheumatic MS may experience a change in symptoms attributable to disease progression related to recurrent episodes of rheu- matic fever leading to further valve damage; progressive narrowing of the mitral valve attributable to leaflet fibro- sis and thickening; progressive pulmonary hypertension; or worsening of concomitant MR or other valve lesions. In addition, symptom status may change with no change in rheumatic MS severity because of an increased he- modynamic load (for example, because of pregnancy), new-onset or rapid AF, fever, anemia, or hyperthyroid- ism, or hemodynamic shifts in the perioperative period of patients undergoing noncardiac surgery. In such cases, a repeat TTE examination can quantify the mitral valve gradient and area, as well as other parameters that may contribute to a change in symptoms. 6.2.1.3. Diagnostic Testing: Routine Follow-Up Rheumatic MS is a slowly progressive disease, char- acterized by a prolonged latent phase between the initial rheumatic illness and the development of valve The latent phase is an interval typically measured in decades in high-income countries but in considerably shorter periods in low- to middle-in- come countries, likely because of recurrent carditis. 