"Patients with chronic mitral regurgitation, in the initial stages of the disease, compensate with more complete left ventricular emptying, resulting in a supraphysiological ejection fraction 1,2. In order to maintain sufficient forward cardiac output, this compensatory mechanism is met with an increased diastolic volume 1,2. This, over time, results in increased compliance of the walls of the left atrium and ventricle as they respond to volume overload in both chambers 1,2. In particular, left atrial enlargement can be responsible for the development of arrhythmias and symptoms of atrial mass-effect on adjacent structures 1,2."
"Cross-sectional imaging is rarely used to evaluate mitral regurgitation, however, demonstrates the same radiographic features appreciated on plain film and echocardiography, but in greater detail 1,7."
"In contrast, in acute mitral regurgitation, sudden regurgitant volume enters into a relatively normal left atrium that does not have years to develop the compliance seen in chronic mitral regurgitation 1,2. This results in a sudden increase in left atrial pressure and pulmonary venous pressures 1,2. Thus, acute pulmonary oedema is a common manifestation in acute mitral regurgitation. Interestingly, because the reflux of blood through the mitral valve in acute mitral regurgitation preferentially moves rightwards posterosuperiorly, the pulmonary oedema is often most noticeable in the upper and middle lobes of the right lung 3."
"The main radiographic differential is that of mitral stenosis which also leads to enlargement of the left atrium. Unlike mitral regurgitation, mitral stenosis does not have left ventricular enlargement and usually has less striking enlargement of the left atrium 2."
"In chronic mitral regurgitation, vasodilators are used to decrease afterload, e.g. ACE inhibitors 8-10. Hypertension is aggressively treated, antiarrhythmics are given where necessary and if there is concomitant mitral valve prolapse or atrial fibrillation, chronic anticoagulation is initiated 8-10."
Expected headings
"Acute mitral regurgitation"
"Chronic mitral regurgitation"
"Ultrasound: echocardiogram"
"Acute mitral regurgitation"
"Chronic mitral regurgitation"
"Complications"
"Mitral regurgitation can be divided into acute and chronic forms, which have differing aetiologies and imaging features 1,2. Furthermore, causes and mechanisms can be divided into primary causes (i.e. degenerative) or secondary causes (i.e. functional) 1,2."
"chordae tendinae rupture seen in myxomatous degeneration (e.g. due to mitral valve prolapse, Marfan syndrome, Ehlers-Danlos syndrome, etc.)"
"congenital valvular malformation (e.g. parachute mitral valve in the Shone complex)"
"mass-effect from left atrial enlargement (e.g. Ortner syndrome, dysphagia megalatriensis)"