Biomedical subjects

M Rashwan

Publications and source records attributed to M Rashwan.

3 recordsLinked to original sources

PubMed1990

Detection and quantitation of ischemic left ventricular dysfunction using a new video intensity technique for regional wall motion evaluation.

Eighty patients with ischemic heart disease and 17 normal subjects were evaluated for left ventricular regional wall motion by means of a new method. The wall motion analysis is based on video intensity. This technique uses a temporally sliding analysis to evaluate the cardiac cycle in 100 msec intervals. Presence of coronary artery disease was defined as more than 50% measured diameter stenosis. Wall motion abnormalities in regions perfused by stenotic vessels were most common in early diastole (76%). Sensitivity of this method at rest in patients with coronary artery disease was 79.7% (p less than 0.0001) and overall accuracy was 84.2% (p less than 0.0001). Abnormalities in both systole and diastole were more common in regions perfused by severe lesions (greater than 75%) than in those perfused by moderately stenotic (less than 75%) vessels (p less than 0.05). A comparison of the new method with phase and amplitude analysis was performed in 15 patients and with two-frame analysis in 40 patients. This new method yielded a higher sensitivity than either of the other two methods.

Adult↗

PubMed1989

Instantaneous transmitral flow using Doppler and M-mode echocardiography: comparison with radionuclide ventriculography.

To improve the accuracy of Doppler echocardiographic indices of left ventricular filling, we derived two indices of instantaneous transmitral flow with the use of Doppler velocities and M-mode echocardiography. These indices were calculated from the product of pulsed Doppler mitral velocities and either the excursion of the anterior mitral leaflet or the separation of both mitral leaflets as measures of the changing mitral orifice area. The derived flow indices and the mitral velocities alone were compared to left ventricular filling as determined by radionuclide ventriculography in 24 patients. When compared as areas under the matched decile divisions of the derived filling sequences by linear regression analysis, the relationship for combined Doppler and M-mode versus radionuclide left ventricular filling was closer to the line of identity (slope = 0.98 and 0.94 using the anterior mitral leaflet and both mitral leaflets, respectively, both p = NS versus the line of identity) than was the relationship for mitral velocities alone versus radionuclide left ventricular filling (slope = 0.74, p less than 0.05 versus the line of identity). The instantaneous mitral volume flow indices more closely resemble the time course and shape of radionuclide left ventricular filling curves than do mitral velocities alone, and the application of these indices should assist the quantitative description by Doppler echocardiography of left ventricular filling.

Aged↗

PubMed1988

Calculating cardiac output from transmitral volume flow using Doppler and M-mode echocardiography.

To simplify transmitral volume flow determination by Doppler echocardiography, a formula for calculating mean mitral valve orifice area using M-mode echocardiography without any 2-dimensional measurements was developed and evaluated in this study. The maximal mitral orifice area was assumed to be circular and its diameter was calculated from the maximal M-mode mitral leaflet separation. The maximal area was multiplied by the mean to maximal anterior mitral leaflet excursion ratio to correct for phasic changes in flow orifice area during ventricular filling. This measurement had a high correlation (r = 0.97, standard error of the estimate + 0.26 cm2) with mean mitral valve orifice area calculated from frame-by-frame analysis of short-axis 2-dimensional echoes in a select group of 10 normal volunteers and 10 patients with cardiomyopathy who had very high quality images of the mitral valve leaflet tips. Cardiac output calculated using the new method for orifice area estimation combined with apex view mitral valve Doppler velocities was then validated in 48 consecutive patients undergoing thermodilution cardiac output determinations with a close correlation between Doppler and thermodilution cardiac output (2.3 to 6.1 liter/min, r = 0.93, standard error of the estimate = 362 ml). The correlation improved when 12 patients with mild mitral insufficiency were excluded (r = 0.95). The M-mode echocardiogram-derived mitral valve orifice method combined with Doppler mitral valve velocities is accurate, easy to perform, has a high success rate and should increase the applicability of Doppler echocardiography for estimation of cardiac output.

Adult↗