ACVIM Stage B2 MMVR is defined as mitral regurgitation with what?

• A. Mitral regurgitation with no remodeling
• B. Mitral regurgitation with evidence of remodeling but no clinical heart failure
• C. Mitral regurgitation with clinical heart failure
• D. Pulmonary edema

Answer: (B)

The main idea is that ACVIM Stage B2 for MMVR represents structural changes from the disease without signs of heart failure. In this stage, the heart shows remodeling—typically enlargement of the left atrium and/or left ventricle due to chronic mitral regurgitation—but the dog remains asymptomatic and does not have clinical heart failure. This distinguishes it from B1, which has structural disease without remodeling, and from stages C or D, where clinical signs of heart failure (such as coughing or trouble breathing, sometimes with pulmonary edema) are present. Pulmonary edema is a sign of heart failure, not stage B2. So the correct description is mitral regurgitation with evidence of remodeling but no clinical heart failure.