A subset of these patients will present with ventricular arrhythmias, mitral annular disjunction, and LV dilation. Alternatively, older popu- lations present with fibroelastic deficiency disease, in which lack of connective tissue leads to chordal rup- ture. The differentiation between these 2 etiologies may have implications for operative intervention. Other CLINICAL STATEMENTS AND GUIDELINES less common causes of chronic primary MR include IE, connective tissue disorders, rheumatic heart disease, cleft mitral valve, and radiation heart disease. If vol- ume overload of chronic primary MR is prolonged and severe, it causes myocardial damage, HF, and eventual death. Correction of the MR before irreversible changes occur can be curative. 7.2.2. Diagnosis and Follow-Up of Chronic Primary MR 7.2.2.1. Diagnostic Testing: Initial Diagnosis Recommendations for Diagnostic Testing: Initial Diagnosis of Chronic MR Referenced studies that support the recommendations are summarized in Online Data Supplement 25. COR LOE Recommendations In patients with known or suspected primary MR, TTE is indicated for baseline evaluation of LV size and function, RV function, LA size, pulmonary artery pressure, and the mechanism and severity of primary MR (Stages A to D).1 5 In patients with primary MR, when TTE provides insufficient or discordant information, TEE is indicated for evaluation of the severity of MR, mechanism of MR, and status of LV function (Stages B to D). 