M mode and two dimensional echocardiography in mitral and aortic regurgitation: pre- and postoperative evaluation of volume overload of the left ventricle.

Both M mode and two dimensional echocardiography are useful in determining the origin of mitral regurgitation. Two dimensional echocardiography appears to be superior to M mode echocardiography in the diagnosis of a flail leaflet, papillary muscle dysfunction and cleft mitral valve. It is possible to differentiate valvular causes from myocardial causes of regurgitation. Unfortunately, the severity of mitral regurgitation is difficult to quantify with either the M mode or the two dimensional technique. Echocardiography does allow differentiation of acute forms of mitral and aortic regurgitation from chronic volume overload of the left ventricle. Rupture of chordae tendineae is the most common cause of acute mitral regurgitation, and two dimensional echocardiography is 96 percent sensitive in its detection. Bacterial endocarditis, flail aortic valve and dissecting aneurysm as causes of acute aortic regurgitation can be detected with two dimensional echocardiography. Systolic left ventricular cavity dimension, percent fractional shortening and ejection fraction are important variables in predicting optimal time for surgery in patients with chronic aortic and mitral regurgitation. The noninvasive technique of echocardiography may be especially useful in decision making in the asymptomatic patient.