Final answer:
The M-mode echocardiographic findings of chronic mitral regurgitation include left atrial enlargement, left ventricular enlargement, and fine diastolic flutter of the mitral valve, but not the Flying W of the pulmonic valve.
Step-by-step explanation:
The M-mode findings associated with significant chronic mitral regurgitation include left atrial enlargement, left ventricular enlargement, and a fine diastolic flutter of the mitral valve. These findings are related to the implications of mitral regurgitation, which leads to increased volume and pressure in the left atrium and left ventricle, as well as abnormal mitral valve motion due to the regurgitant jet.
The option that is not associated with chronic mitral regurgitation is the Flying W of the pulmonic valve. This is because the pulmonic valve is not involved in mitral valve disorders; it is associated with right ventricular or pulmonary artery abnormalities, which are unrelated to mitral regurgitation.