Prediction Of Subclinical Left Ventricular Dysfunction With Velocity Vector Imaging In Patients With Mitral Stenosis

Background: The predominant cause of mitral stenosis(MS) is rheumatic fever. Generally speaking, left ventricular(LV) systolic functions are well preserved in the patients with pure mitral stenosis. However, ultrastructural changes may occur in left ventricular cells and regional function of LV myocardium may be damaged in some patients with MS. Patients with MS has been assumed to have isolated diastolic dysfunction in early stage and studied only on radial left ventricular function previously. The importance of the longitudinal LV function may be recognized in recent years. Although long axis left ventricular function is important and sensitive , the assessment is too difficult and complex in conventional ways. It is verified that velocity vector imaging (VVI) can offer an objective mean to quantify global and regional LV function and can improve the accuracy and the sensitivity in contrast to the conventional echocardiography. As we all known, the longitudinal systolic contraction of the left ventricular has not been studied in domain.Objective: To investigate the longitudinal contraction of the left ventricle in pure mitral stenosis with normal ejection fraction by VVI. To find the difference between these patients and healthy individuals. To characterize long axis left ventricle systolic function in the patients with mitral stenosis. To discuss and verify the important clinical value of VVI in quantitatively evaluating segmental systolic function of left ventricular.Methods: We examined pure mitral stenosis patients with ejection fraction (EF) >55% and fractional shortening (FS) >25%. All the patients were matched for sex and age. Patients who had known coronary artery disease , diabetes mellitus, hypertension, significant aortic regurgitation, aortic stenosis, hyperthyroidism, previous aorta or mitral valve operation, chronic obstructive pulmonary disease, or atrioventricular conduction abnormalities were excluded from the study. Longitudinal velocity in systolic period,strain and strain rate in systolic and diastolic (early and later ) period were obtained from 1～2 consecutive heartbeats in 16 segments respectively to assess left ventricular longitudinal contraction . The parameters were quantitatively analyzed between the two groups.Results: Compared with the normal group, all of the measured parameters of the MS were significantly lower (P<0.01), except the parameter of later diastolic strain(P>0.05). There was no statistically significant difference of left ventricular EF between two groups(P>0.05). It is found that myocardial velocities decrease from base to apex in 2 group persons. Besides, systolic strain is constant throught the myocardial wall in two groups.Conclusion: The longitudinal systolic contraction was significantly decreased in pure mitral stenosis with normal ejection fraction. VVI could discover the early change of myocardium function in the patients with mitral stenosis. VVI was feasible and liable in clinical settings. VVI was also a useful method which can quantitatively assess ventricular regional function.