Severe mitral valve regurgitation:
The mitral valve is a leaflets valve that separates the left atrium from the left ventricle. The valve opens to allow blood flow from the atrium to the ventricle during diastole, and closes to prevent backflow from the ventricle to the atrium during systole. MR occurs when the mitral valve does not close properly, resulting in leakage of blood back into the left atrium during systole. This results in volume overload of the left atrium, which can lead to left atrial enlargement and, ultimately, left ventricular dysfunction.
Transthoracic echocardiography (TTE) is typically used as the initial screening test, as it is widely available, relatively inexpensive, and can be performed quickly at the bedside. TTE allows for assessment of heart size, valvular anatomy, and valvular function. Doppler echocardiography can be used to quantify MR by measuring gradient across the valve, by assessing regurgitant volume, or by measuring the vena contracta. A regurgitant volume ≥ 60 mL, a vena contracta more ≥ 0.7 cm, a central jet MR >40% LA, or a holocystolic eccentric jet MR indicate a severe MR.