Isolated mitral valve prolapsus does not affect left ventricular function: Insights from tissue-Doppler echocardiography

Abstract

Aim: Idiopathic mitral valve prolapsus (MVP) is characterized by myxomatous degeneration of mitral valve. The most common determinant of cardiovascular mortality in patients with MVP is left ventricular (LV) dysfunction. Therefore we aimed to evaluate LV functions of cases with isolated MVP by tissue Doppler echocardiography (TDE). Method: Twenty five patients with MVP (mean age, Sm (11.6±2.8 vs. 9.4±1.0, p=0.001; 13.0±3.9 vs. 9.2±2.3, p=0.001 respectively). formed in the left lateral decubitus position, using ATL-5000 standard ultrasound machine (Advance Technology La¬bo¬ratories, Bothell, Washington) with a 2.5-3.5 MHz transducer. Images were obtained in the standard tomographic views of the LV (parasternal long and short axis and apical four-chamber, two-chamber, and long-axis views). Mitral inflow velocities were recorded by using conventional pulsed-wave Doppler echocardiography, positioning a sample volume at the level of the mitral leaflet tips in the apical four-chamber view. The peak early diastolic velocity (E), peak late diastolic velocity (A), E/A ratio, isovolumetric relaxation time (IRT), and E-wave deceleration time (EDT) were measured on line. Recordings were performed at the end of normal expiration in order to eliminate the effects of respiration on the parameters studied. Left ventricular diameters and wall thicknesses were measured from the two-dimensional targeted M-mode echocardiographic tracings in the parasternal long axis, according to the criteria of the American Society of Echocardiography (9). The LV end-diastolic and end-systolic volumes at rest were computed from two-and four-chamber views, using a modified Simpson's method, and the LV EF was calculated. ConclusionThe echocardiograph machine was used to acquire colour tissue Doppler data using a high frequency acquisition. Color-coded TDE cine loops obtained with >100 frames/s from the apical 4-chamber view were used for TDE measurements. The filter settings were kept low (50 Hz), and gains were adjusted at the minimal optimal level to minimize noise and eliminate the signals produced by the transmitral flow. A 3.5 mm sample volume was used. In the apical 4-chamber view, myocardial peak systolic (Sm, cm/s), early (Em, cm/s) and late (Am, cm/s) diastolic filling velocities, Em/Am ratio, isovolumetric contraction time (ICT), isovolumetric relaxation time (IRT) and ejection time (ET) were obtained by placing a tissue Doppler sample volume in the basal segments of the inferior-septal and lateral wall. All examinations were performed using harmonic imaging. MPI was calculated using (ICT+IRT)/ET Formula (10). Mean myocardial velocities of LV, mean MPI and mean Em/Am ratios were calculated by dividing the sum of Sm, Em, Am velocity and Em/Am ratio measured from two different parts of LV by two.Three consecutive cycles were averaged for every parameter. The operator was blinded to the clinical details and results of the other investigations in each subject and control. The intraobserver variability of echocardiographic measurement...