Measurement of aortic regurgitation by Doppler echocardiography.

In an attempt to develop a new approach to the non-invasive measurement of aortic regurgitation, transmitral volumetric flow (MF) and left ventricular total stroke volume (SV) were measured by Doppler and cross sectional echocardiography in 23 patients without aortic valve disease (group A) and in 26 patients with aortic regurgitation (group B). The transmitral volumetric flow was obtained by multiplying the corrected mitral orifice area by the diastolic velocity integral, and the left ventricular total stroke volume was derived by subtracting the left ventricular end systolic volume from the end diastolic volume. The aortic regurgitant fraction (RF) was calculated as: RF = 1 - MF/SV. In group A there was a close agreement between the transmitral volumetric flow and the left ventricular total stroke volume, and the difference between the two measurements did not differ significantly from zero. In group B the left ventricular total stroke volume was significantly larger than the transmitral volumetric flow, and there was good agreement between the regurgitant fractions determined by Doppler echocardiography and radionuclide ventriculography. Discrepancies between the two techniques were found in patients with combined aortic and mitral regurgitation or a low angiographic left ventricular ejection fraction (less than 35%). The effective cardiac output measured by Doppler echocardiography accorded well with that measured by the Fick method. Doppler echocardiography provides a new and promising approach to the non-invasive measurement of aortic regurgitation.     

Measurement of mitral regurgitation by Doppler echocardiography.

In an attempt to develop a new approach to the non-invasive measurement of mitral regurgitation, Doppler echocardiography and left ventriculography were performed in 20 patients without valvar heart disease (group A) and in 30 patients with pure mitral regurgitation (group B). Volumetric flows through the aortic and the mitral orifices were determined by Doppler echocardiography. Aortic flow (AF) was calculated as the product of the aortic orifice area and the systolic velocity integral. The mitral flow (MF) was calculated as the product of the corrected mitral orifice area and the diastolic velocity integral. The mitral regurgitant fraction (RF) was calculated as RF = 1 - AF/MF. In group A aortic and mitral flow were very similar and the difference between the two did not differ significantly from zero. In group B the mitral flow was significantly larger than the aortic flow. There was a good correlation (r = 0.82) between the regurgitant fraction determined by Doppler echocardiography and the regurgitant grades determined by left ventriculography. The regurgitant fraction increased significantly with each grade of severity. These results show that Doppler echocardiography can be used to give a reliable measure of both aortic and mitral flow. This technique is a new and promising approach to the non-invasive measurement of mitral regurgitation.     

Measurement of mitral regurgitation by Doppler echocardiography

In an attempt to develop a new approach to the non-invasive measurement of mitral regurgitation, Doppler echocardiography and left ventriculography were performed in 20 patients without valvar heart disease (group A) and in 30 patients with pure mitral regurgitation (group B). Volumetric flows through the aortic and the mitral orifices were determined by Doppler echocardiography. Aortic flow (AF) was calculated as the product of the aortic orifice area and the systolic velocity integral. The mitral flow (MF) was calculated as the product of the corrected mitral orifice area and the diastolic velocity integral. The mitral regurgitant fraction (RF) was calculated as RF = 1 - AF/MF. In group A aortic and mitral flow were very similar and the difference between the two did not differ significantly from zero. In group B the mitral flow was significantly larger than the aortic flow. There was a good correlation (r = 0.82) between the regurgitant fraction determined by Doppler echocardiography and the regurgitant grades determined by left ventriculography. The regurgitant fraction increased significantly with each grade of severity. These results show that Doppler echocardiography can be used to give a reliable measure of both aortic and mitral flow. This technique is a new and promising approach to the non-invasive measurement of mitral regurgitation.     

Doppler echocardiography measurement of the regurgitation fraction in patients with aortic valve insufficiency

The purpose of this study was to assess the clinical utility of pulsed Doppler echocardiography in the determination of regurgitant fraction in patients with aortic regurgitation. Therefore, in 33 unselected consecutive patients with aortic regurgitation, and in 16 patients without heart disease Doppler echocardiography was performed to measure blood flow at the aortic and pulmonary valve. The regurgitant blood flow (RBV) was calculated as the difference of the stroke volumes measured at the aortic and pulmonary valve. The regurgitant fraction (RF) was computed as RBV/aortic flow. At cardiac catheterization RBV and RF were calculated from the left ventricular angiographic stroke volume and the stroke volume measured by thermodilution technique. Four patients were excluded because of technically poor left-ventricular angiograms. In eight patients with aortic regurgitation Doppler measurement of RBV and RF was impossible. The correlations between the invasive and the Doppler data were significant in 21 patients with aortic regurgitation (RBV: r = 0.87, SEE = 16.1 ml; RF: r = 0.90, SEE = 8.1%). However, the RF (41.6 +/- 17.6%) was overestimated by Doppler echocardiography (46.0 +/- 17.9%; p les than 0.021). In the control group RBV ranged between -8.1 ml and 10.5 ml and RF between -13.3% and 7.4%. Thus, pulsed Doppler echocardiography is clinically useful in determination of the regurgitant fraction in about 70% of patients with pure aortic regurgitation. The Doppler method, however, is limited in the diagnosis and quantification of mild aortic regurgitation.     

Quantitation of mitral regurgitation by Doppler echocardiography

The evaluation and care of patients with mitral regurgitation would be facilitated by an easy, reproducible and noninvasive method that could quantitate the hemodynamic burden. In this study, we describe a new Doppler echocardiographic method that measures the regurgitant fraction and we compare it with angiographic and scintigraphic methods. A total of 27 patients with mitral regurgitation were evaluated by echocardiography and either cardiac catheterization or scintigraphy. With two-dimensional echocardiography, diastolic and systolic volumes were measured to derive the left ventricular stroke volume (LVSV). The forward stroke volume (FSV) was obtained from the product of M mode-derived aortic valve area and ascending aortic flow velocity integral assessed by continuous-wave Doppler. Regurgitant fraction was calculated as follows: (LVSV - FSV)/LVSV. Comparisons showed that regurgitant fraction calculated by Doppler echocardiography correlated with regurgitant fraction determined by both cardiac catheterization (r = .82) and by scintigraphy (r = .89). There was, however, an important interobserver variability within each method: 10%, 13%, and 11% for Doppler echocardiography, angiography, and scintigraphy, respectively. In conclusion, Doppler echocardiography can be used to quantitate mitral regurgitation. Serial noninvasive determinations of regurgitant fraction may be useful in the evaluation of therapy and in the follow-up of patients with mitral insufficiency.     

A simplified method for determining regurgitant fraction by Doppler echocardiography in patients with aortic regurtitation

Objectives. This study attempted to develop and validate a simple method for calculating aortic regurgitant fraction by use of pulsed wave Doppler echocardiography.Background. Although several investigators have been able to determine aortic regurgitant fraction by Doppler echocardiography, the methods used require accurate determination of the cross-sectional areas of intracardiac sites at which the volumetric flow is calculated.Methods. Our concept was based on a constant relation that exists between the cross-sectional area of the left ventricular outflow tract and the mitral valve annulus in normal subjects. To verify this, we used Doppler echocardiography to measure the flow velocity integral of the left ventricular outflow tract and the mitral annulus in the apical view in 50 normal subjects (32 men, 18 women, mean age 34 years).Results. Close correlation (r = 0.95) was observed between the flow velocity integral (FVI) of the outflow tract (OT) and that of the mitral annulus (MA): FVI_MA/FVI_OT= 0.77. Because mitral flow equals aortic flow in normal subjects, the ratio of the cross-sectional area of the mitral annulus to that of the outflow tract was 1/0.77. In patients with aortic regurgitation, the regurgitant fraction (RF) = (Aortic flow − Mitral flow)/Aortic flow = 1 − Mitral flow/Aortic flow. Substituting 0.77 for the area component of flow, RF = 1 − (1/0.77) · (FVI_MA/FVI_OT). To evaluate the accuracy of this method, we compared the regurgitant fraction derived by Doppler echocardiography with that from catheterization findings in 20 patients with aortic regurgitation (an isolated lesion was found in 14). The regurgitant fraction by catheterization was the difference between total (angiographic) and forward (thermodilution) stroke volumes as a percent of total flow. Good correlation was observed between catheterization and Doppler regurgitant fraction (r = 0.88, SEE 9%, p < 0.01).Conclusions. Thus, regurgitant fraction can be estimated from Doppler echocardiography in patients with aortic regurgitation by a method that requires only measurements of the flow velocity integral from the mitral annulus and left ventricular outflow tract.     

Quantitative assessment of aortic regurgitation by colour flow Doppler in an open chest canine model

Colour flow Doppler maps the extent of the flow velocity disturbance of aortic regurgitation onto the two dimensional echocardiographic image of the left ventricular cavity. The spatial extent of this flow velocity disturbance expressed as a percentage of end diastolic left ventricular cavity area (CD%) was compared to regurgitant fraction (RF), measured volumetrically, in nine open chest dogs with varying degrees of surgically created aortic regurgitation (RF 0-85%). Right heart bypass controlled venous return to the left atrium and hence net left ventricular output, while total left ventricular output was measured with an aortic electromagnetic flow probe under various loading conditions, achieving mean diastolic transvalvular pressure gradients of 23-114 mm Hg, net left ventricular outputs of 750-3000 ml.min-1 and diastolic filling periods of 162-320 ms. A linear correlation between CD% and RF (r = 0.89) was demonstrated over this wide range of loading conditions. At a given transvalvular diastolic pressure gradient [68(SD9) mm Hg] CD% was linearly proportional to regurgitant aortic orifice area (r = 0.87). Thus CD% is proportional to the volumetric severity of aortic regurgitation under a wide range of haemodynamic conditions and varies appropriately with regurgitant aortic orifice area when diastolic transvalvular pressure gradient is held constant. The application of these principles to the non-invasive quantitation of valvular regurgitation by colour Doppler appears feasible.     

Noninvasive evaluation of the magnitude of aortic and mitral regurgitation by means of Doppler two-dimensional echocardiography

Using transmitral flow velocity and left ventricular ejection flow velocity, we measured left ventricular inflow volume (LVIV) and left ventricular outflow volume (LVOV) by pulsed Doppler echocardiography in 73 patients who had mitral valve regurgitation (MR), aortic valve regurgitation (AR), or no valvular regurgitation. Doppler-determined regurgitant volume (DOPRV), Doppler-determined regurgitant fraction (DOPRF), total stoke volume, and forward stroke volume were calculated to compare the severity assessed by angiographic scoring and the regurgitant fraction determined by radionuclide angiography (RIRF). In 17 patients with MR, LVIV (84.4 +/- 20.4 ml) was significantly greater (p less than 0.01) than LVOV (52.5 +/- 15.7 ml). LVOV, which is equivalent to forward stroke volume, was lower in patients with MR (52.2 +/- 15.7 ml) than in normal subjects (67.0 +/- 15.7 ml). In 15 patients with AR, LVOV (121.7 +/- 61.1 ml) was significantly greater (p less than 0.01) than LVIV (75.1 +/- 28.1 ml) and LVOV, which is equivalent to total stroke volume, was greater in patients with AR (121.7 +/- 61.1 ml) than in normal subjects (64.0 +/- 14.4 ml). DOPRF correlated with RIRF (r = 0.79, p less than 0.01, n = 11). DOPRV (mild: 10.5 +/- 8.5 ml; moderate: 28.8 +/- 13.6 ml; severe: 74.5 +/- 36.7 ml) and DOPRF (mild: 13.7% +/- 11.5%; moderate: 33.1% +/- 14.2%; severe: 52.6% +/- 15.3%) increased markedly with the severity of regurgitation as assessed by cineangiography. In AR, total stroke volume influenced both forward stroke volume and regurgitant volume, and in MR, regurgitant volume influenced both total stroke volume and forward stroke volume. Total stroke volume in AR and regurgitant volume in MR may play a key role in valvular regurgitation.     

Cross-sectional visualization of regurgitant jet by color flow mapping to evaluate aortic regurgitation

In the noninvasive evaluation of aortic regurgitation by Doppler echocardiography, flow mapping of the aortic regurgitant jet using the long-axis approach is of limited value in cases of combined mitral stenotic lesions. This is because the transmitral flow yields flow disturbances in the left ventricle, making it difficult to identify the extent of the aortic regurgitant jet. To overcome these limitations, the severity of aortic regurgitation was evaluated using the cross-sectional area of the aortic regurgitant jet at the level of the aortic valve as visualized by color flow imaging technique. The study population consisted of 16 patients with aortic regurgitation (10 with pure aortic regurgitation, five with superimposed mitral stenosis, and one with mitral valve replacement). Three normal subjects served as controls. The cross-section of the aortic regurgitant jet was visualized as a mosaic of yellow and blue in all patients with aortic regurgitation, but not in any of the controls. Planimetric measurements of the cross-sectional area of the regurgitant jet (J) and the aortic annulus area (Ao) were performed, and the Doppler parameter, J/Ao, was calculated. As a reference, the aortic regurgitant fraction (RF) was calculated from Doppler measurements of systolic aortic and pulmonary flows (AF and PF); RF (%) = (AF - RF)/AF x 100. The Doppler parameter, J/Ao, correlated well with the Doppler measurement of RF (r = 0.82, p less than 0.005), irrespective of the presence of associated mitral lesions. Thus, the cross-sectional area of the aortic regurgitant jet determined by color flow imaging technique would be a useful estimate of the severity of aortic regurgitation, even in the presence of associated mitral stenotic changes.     

A new approach to noninvasive evaluation of aortic regurgitant fraction by two-dimensional Doppler echocardiography

The aortic regurgitant fraction was estimated noninvasively in 20 patients with aortic regurgitation from systolic aortic and pulmonary volume flow determined by duplex Doppler echocardiography. By assuming that an excess of the aortic volume flow (AF) compared with the pulmonary volume flow (PF) is due to aortic regurgitant flow, the aortic regurgitant fraction (RF) was calculated as follows: RF(%) = (AF - PF)/AF X 100. The aortic and pulmonary volume flows were determined as products of systolic integrals of ejection flow velocities and cross-sectional areas of the left and right ventricular outflow tracts, respectively. The Doppler estimate of the regurgitant fraction was compared by semiquantitative grading (1+ to 4+) by cineaortography and with the measurement of regurgitant fraction by catheter technique. The mean Doppler-determined aortic regurgitant fraction was 2.4% for normal subjects, 28.0% for the patients with 1+, 32.6% for the patients with 2+, 53.3% for the patients with 3+, and 62.4% for the patients with 4+. A fair correlation was found between Doppler estimates of regurgitant fraction and semiquantitative cineaortographic grades (r = .80, p less than .01). In the patients without associated mitral regurgitation, a close correlation was observed between Doppler and catheter estimates of regurgitant fraction (r = .96, p less than .01; y = 1.0x - 0.08). In the patients with associated mild mitral regurgitation, however, Doppler estimates of regurgitant fraction substantially underestimated those determined by the conventional catheter technique, which cannot separately quantitate the aortic regurgitant fraction in the presence of mitral regurgitation. These observations indicate that the proposed Doppler technique provides a useful method to evaluate the aortic regurgitant fraction specifically regardless of the presence of associated mitral lesions.     

Effects of Dobutamine Infusion on Mitral Regurgitation

Both intensity of mitral regurgitant murmur and color-coded Doppler regurgitant signal area have been reported to correlate with the degree of regurgitation. To evaluate the relationship between the intensity of regurgitant murmur and severity of mitral regurgitation, phonocardiography, echocardiography, and Doppler ultrasound were performed in 18 patients with mitral regurgitation before and during dobutamine infusion. Mitral regurgitation was due to mitral valve prolapse with ruptured chordae tendineae in 8 patients, rheumatic change in 5 patients, and dilated cardiomyopathy in 5 patients. With intravenous dobutamine infusion, heart rate (77–103 beats/min), systolic blood pressure (119–144 mmHg), peak mitral regurgitant jet velocity (4.5–5.4 m/sec), intensity of mitral regurgitant murmur (to 201% of that before infusion in early systole) increased, while left ventricular end-diastolic volume (124–102 mm), left ventricular end-systolic volume (57–42 mm), mitral anular diameter (33–28mm), and color Doppler mitral regurgitant signal area (704–416 mm²) decreased (P < 0.05). Total (forward + backward) left ventricular stroke volume (66–61 mL/beat) showed no change. Dobutamine decreased mitral regurgitant flow/beat, regardless of etiology of mitral regurgitation, which was probably due to the decrease of left ventricular size and mitral annular diameter. Although total (forward + backward) left ventricular stroke volume was unchanged, dobutamine effectively increased forward left ventricular stroke volume by decreasing backward regurgitation. Mitral regurgitant murmur became louder despite the decrease of mitral regurgation, indicating the uselessness of auscultation in the grading of the severity of mitral regurgitation.     

Left atrial overload can be used to estimate mitral regurgitant volume

This study was conducted to assess the accuracy of the estimated mitral regurgitant volume using both the left atrial filling volume and the systolic component of pulmonary vein flow expressed as the percent of its total. Since mitral regurgitation fills the left atrial chamber, the variation in atrial volume during ventricular systole has been proposed as a means to evaluate the severity of regurgitation. Although the correlation with invasive grading of mitral regurgitation is good, there is an unacceptable overlap among grades caused by the absence of information concerning pulmonary vein flow, which enters the left atrium while regurgitation occurs. The Doppler regurgitant volume, or Dp-RVol (mitral stroke volume minus aortic stroke volume) was quantified in 74 patients with any degree and etiology of mitral regurgitation. Atrial volumes were measured from the four-chamber apical view (biplane area-length method). The systolic time-velocity integral of pulmonary vein flow was expressed as the percent of the total (PVs%) (systolic-diastolic) time-velocity integral. These parameters were subjected to multivariate analysis and a regression equation was obtained. The equation was subsequently applied to a group of 31 patients without mitral regurgitation, as evaluated by color Doppler or continuous-wave Doppler and to the overall population (105 patients) in order to estimate the mitral regurgitant volume. In 74 patients with mitral regurgitation, the Doppler regurgitant volume was univariately correlated with the left atrial filling volume (r= 0.74; p<0.0001) and the systolic pulmonary vein velocity integral expressed as the percent of the total (r=0.67; p<0.0001). In multiple regression analysis, the combination of atrial filling and the pulmonary vein velocity integral provided the more accurate estimation of the regurgitant volume (R2=0.84; standard error of the estimate [SEE], 13.9 mL; p<0.0001; Dp-RVol equals 7.84+[1.08*left atrial filling volume] 2 [0.839*PVs%]). In 31 patients with no mitral regurgitation detected by color Doppler or continuous wave Doppler the estimated regurgitant volume was 4.3±6.6 mL. In the overall population the estimated regurgitant volume and the Doppler regurgitant volume correlated well with each other (R2=0.85; SEE, 11.5 mL; p<0.0001). The equation was 100% sensitive and 98% specific in detecting a regurgitant volume higher than 55 mL. The combination of the atrial filling volume and the systolic pulmonary vein time-velocity integral expressed as the percent of the total allows reliable estimation of the regurgitant volume in patients with mitral regurgitation. (c)2001 CHF, Inc.     

Diastolic mitral regurgitation in acute but not chronic aortic regurgitation: implications regarding the mechanism of mitral closure

In acute aortic regurgitation, left ventricular pressure rises rapidly during diastole, which produces presystolic mitral valve closure. This does not occur in chronic aortic regurgitation. Since normal, nonregurgitant mitral valve closure may depend on properly coordinated atrial and ventricular contractions, we hypothesized that abnormal mitral valve closure occurring before systole in acute aortic regurgitation may produce diastolic mitral regurgitation detectable by Doppler echocardiography. Accordingly, we performed ultrasonic Doppler examination of seven patients with acute aortic regurgitation and 12 patients with chronic aortic regurgitation. Regurgitant aortic flow was severe in all cases. Doppler sampling within the left atrium demonstrated regurgitant mitral flow in late diastole in all patients with acute aortic regurgitation. The onset of diastolic mitral regurgitation coincided with mitral valve preclosure in patients with acute aortic regurgitation and occurred regardless of the position of the mitral leaflets at the initiation of closure. In contrast, none of the 12 patients with chronic aortic regurgitation had mitral valve preclosure or diastolic mitral regurgitation (p less than 0.05 versus acute aortic regurgitation). We conclude that diastolic mitral regurgitation accompanies mitral valve preclosure, which occurs in acute but not chronic aortic regurgitation. Thus diastolic mitral regurgitation may be a Doppler sign of acute aortic regurgitation, in the absence of a markedly prolonged PR interval. Furthermore, this observation suggests that normal, nonregurgitant mitral closure requires more than an increase in left ventricular pressure above left atrial pressure, regardless of the position of the mitral leaflets before closure.     

Noninvasive quantification of mitral regurgitation in dilated cardiomyopathy: correlation of two Doppler echocardiographic methods

The presence and severity of functional mitral regurgitation were quantified by Doppler echocardiography in 17 patients with dilated cardiomyopathy and no evidence of primary valvular disease. Mitral regurgitant fraction was greater than 20% in 11 of the 17 patients, and exceeded 40% in four patients. Total stroke volume, calculated from the difference between end-diastolic and end-systolic volumes obtained by two-dimensional echocardiography, correlated well with mitral valve inflow determined by Doppler echocardiography (r = 0.90, p less than 0.001). Similarly, mitral regurgitant volume, calculated as the difference between echocardiographic total stroke volume and forward aortic volume obtained by Doppler echocardiography, correlated well with regurgitant volume calculated as the difference between mitral valve inflow and forward aortic flow, both determined by Doppler echocardiography (r = 0.90, p less than 0.001). Accordingly, functional mitral regurgitation can be conveniently demonstrated in patients with dilated cardiomyopathy by two different Doppler echocardiography methods, whose results are closely correlated. Mitral regurgitant fraction is greater than 20% in two thirds of the patients with a dilated cardiomyopathy.     

Quantification of regurgitant fraction in mitral regurgitation by cardiovascular magnetic resonance: comparison of techniques

BACKGROUND AND AIM OF THE STUDY: Cardiovascular magnetic resonance (CMR) assessment of mitral regurgitant volume from the subtraction of the right ventricular stroke volume (RVSV) from left ventricular stroke volume (LVSV) has commonly been performed using volumetric techniques. This is sensitive to errors in RVSV visualization and regurgitation of other heart valves, and therefore subtracting aortic flow volume from LVSV may be preferable. The study aim was to compare both techniques in a single CMR examination. METHODS: Twenty-eight patients with isolated mitral regurgitation underwent left ventricular (LV) and right ventricular (RV) volumetry and aortic flow volume measurements. Mitral regurgitant fraction (RF) was calculated as either RF(VOL) = [LVSV - RVSV] or RF(FLOW) = [LVSV - aortic flow volume], both expressed as a fraction of LVSV. The agreement of the measurements was assessed as a measure of robustness in clinical practice. RESULTS: There was good agreement between aortic and pulmonary flow (mean +/- SD difference -0.8 +/- 8.1 ml), and aortic flow volume and RVSV by volumetry (mean difference -2.6 +/- 11.8 ml). Intra- and interobserver variability (SD) of aortic flow volume (+/-6.6 ml and +/-5.3 ml) was superior to that of the RVSV (+/-8.5 ml and +/-12 ml). The intra- and inter-observer variability (SD) of RF(FLOW) was lower (+/-4.8% and +/-7.7%) than by RF(VOL) (+/-6.7% and +/-8.8%). CONCLUSION: The RF(FLOW) technique maximized intra- and inter-observer agreement, and is the optimal CMR technique to quantify mitral regurgitation. RF(FLOW) also has the advantage of allowing correction for aortic regurgitation when it is present, and is potentially independent of the effects of tricuspid and pulmonary regurgitation.     

Value of color Doppler estimation of regurgitant volume in patients with chronic aortic insufficiency

We studied 16 patients with chronic aortic insufficiency to compare a method for measuring regurgitant volume with color Doppler flow mapping to stroke count ratio determined by radionuclide ventriculography and to ventricular volumes assessed by two-dimensional echocardiography. A real-time color flow map of the left ventricular was obtained from an apical two- and five-chamber view and the maximal mosaic pattern of diastolic turbulent flow was planimetered as a reflection of the maximal regurgitant volume using biplane Simpson's rule. The maximal Doppler regurgitant volume evaluated by color Doppler flow mapping correlated with the stroke count ratio measured by scintigraphy (r = 0.86, SEE = 11 cc). There were significant relationships between maximal regurgitant volume measured by color Doppler and echocardiographic left ventricular end-diastolic volume (r = 0.88), left ventricular end-systolic volume (r = 0.77), and left ventricular mass (r = 0.71). Patients with larger regurgitant volumes tended to have a larger left ventricular end-diastolic volume-to-mass ratio (r = 0.56). Thus maximal aortic regurgitant volume can be estimated noninvasively with color Doppler flow mapping. The measurement appears to relate to left ventricular morphologic changes occurring in this condition and it may prove to be useful in assessing patients with chronic aortic insufficiency and in determining their long-term management.     

Quantification of regurgitant lesions by MRI

We examined 46 patients with angiographically documented regurgitant lesions (26 patients with mitral regurgitation, 20 patients with aortic regurgitation) using an 0.5 Tesla magnet. In each patient a multislice-multiphase spinecho sequence in sagittal-coronal double angulated plane was performed to assess left and right ventricular volumes, ejection fraction and regurgitant fraction. Additionally a blood flow sensitive gradient echo technique was done to visualize direction and extension of the regurgitant jet. MRI data were compared with quantitative and qualitative assessment of regurgitation by angiography and echocardiography. Using the gradient echo technique MRI could demonstrate the regurgitant jet in all patients. A linear correlation for volume parameters by MRI and angio was found with best correlation for the left ventricular stroke volume (r=0.82, p<0.0001). Furthermore MRI regurgitant fraction correlated with angiographically determined regurgitant fraction in patients with aortic regurgitation (r=0.91, p<0.0001) and mitral regurgitation (r=0.67, p<0.001), respectively. Semiquantitative assessment of regurgitation by gradient echo technique showed an agreement with angiographic grading by Sellers in 70% of mitral and 75% of aortic regurgitation, respectively. The comparison of MRI and color Doppler sonography showed only moderate correlation of r=0.72 (p<0.01).     

Quantification of left-side intracardiac pressures and gradients using mitral and aortic regurgitant velocities by simultaneous left and right catheterization and continuous-wave doppler echocardiography

Noninvasive determination of left-side intracardiac pressures is of clinical importance in many cardiac diseases. To test the reliability and accuracy of left-side intracardiac pressure measurements by continuous-wave Doppler echocardiography, using left-side valvular regurgitations, 47 patients with mitral regurgitation, with or without associated aortic regurgitation, underwent simultaneous Doppler and left and right catheterization. Doppler-derived left atrial and ventricular end-diastolic pressures were respectively estimated by subtracting mitral regurgitant gradient from systolic blood pressure and by diastolic blood pressure minus aortic regurgitant gradient. There were high correlations of mitral (r = 0.961) and aortic regurgitant gradients (r = 0.896) and of left atrial (r = 0.945) and ventricular end-diastolic pressures (r=0.854) between noninvasive and invasive measurements. Also, agreement analyses showed that there was close agreement between the two technical measurements for each parameter. The present study concluded that continuous-wave Doppler echocardiography provides a reliable and accurate method for the noninvasive evaluation of left-side intracardiac pressures and gradients in patients with mitral and aortic regurgitations.     

A real-time three-dimensional echocardiographic quantitative analysis of left atrial function in left ventricular diastolic dysfunction

The evaluation of left ventricular diastolic function provides important information about hemodynamics and has prognostic implications for various cardiac diseases. In particular, left atrial (LA) volume is an increasingly significant prognostic biomarker for diastolic dysfunction. The aim of this study was to assess left ventricular diastolic function by measuring changes in LA volume using real-time 3-dimensional echocardiography. The 106 subjects were divided into 4 groups (normal, impaired relaxation, pseudonormal, and restrictive) on the basis of diastolic function, as assessed by transmitral flow patterns. LA volume was measured during a heart cycle using real-time 3-dimensional echocardiography. LA stroke volume (maximum LA volume - minimum LA volume) and the LA ejection fraction (LA stroke volume/maximum LA volume x 100) were calculated using Doppler imaging to assess their correlation with other parameters used to evaluate left ventricular diastolic function, including transmitral flow pattern and early diastolic mitral annular velocity (E'). LA volume indexed to body surface area was dilated in subjects with left ventricular diastolic dysfunction, whereas the LA ejection fraction was lower. The maximum LA volume, minimum LA volume, and LA ejection fraction were significantly different between each group, and each was significantly correlated with the ratio of early diastolic transmitral flow velocity (E) to E' (E/E'). The LA ejection fraction correlated best with E/E' (r = -0.68, p <0.0001). In conclusion, cyclic changes in LA volume could be measured using real-time 3-dimensional echocardiography, and measuring LA function with this method may be a viable alternative for the accurate assessment of left ventricular diastolic function.     

Time variation of mitral regurgitant flow in patients with dilated cardiomyopathy

Angiographic results in patients with mitral regurgitation suggest that up to 50% of the regurgitant volume occurs during the preejection period. This contrasts markedly with the electromagnetic measurements of mitral regurgitant flow in anesthetized dogs, which suggest that only 5% of mitral regurgitant flow occurs during the preejection period. Therefore, we used two-dimensional and Doppler echocardiography to quantify mitral regurgitation during aortic ejection and in the preejection and postejection periods in eight patients with severe heart failure. Mitral regurgitant volume (RV) was calculated as the difference between total stroke volume (by two-dimensional echocardiography) and forward aortic flow (by pulsed Doppler). Regurgitant velocity (V) and time (RT) were measured by continuous-wave Doppler, and the mean regurgitant area (RAm) was calculated from the RT and mean regurgitant velocity (Vm): RAm = (RV/RT)/Vm. As a first approximation, the RA was assumed to be constant during systole, and the regurgitant volume during aortic ejection and during the preejection and postejection periods was calculated from: RVi = (Vmi) (RTi) (TAm), where Ti represents the duration of the appropriate period. Percentages of total regurgitant volume occurring during the preejection, ejection, and postejection periods were 13 +/- 4%, 79 +/- 5%, and 8 +/- 5%, respectively. Thus, in contrast to previously reported angiographic studies, mitral regurgitation occurs predominantly during the aortic ejection period. These results were not substantially changed by assuming a 20% reduction in effective regurgitant orifice area between the preejection and ejection periods and are consistent with data from chronically instrumented dogs with mitral regurgitation.(ABSTRACT TRUNCATED AT 250 WORDS)