Factors influencing pulmonary venous flow velocity patterns in mitral regurgitation: an in vitro study

OBJECTIVES: The aim of this study was to investigate factors affecting pulmonary venous flow patterns in mitral regurgitation. BACKGROUND: Although pulmonary venous flow velocity patterns have been reported to be helpful in assessing the severity of mitral regurgitation, the influence of regurgitant jet direction, pulmonary venous location and left atrial pressures on pulmonary venous flow patterns has yet to be clarified. METHODS: The mitral regurgitant jet was produced by a pulsatile piston pump at 10, 30 and 40 ml/beat through a circular orifice, whereas the pulmonary venous flow was driven by gravity. Four different patterns of pulmonary venous flow and mitral regurgitation were examined. The V wave pressure was set at 10, 30 and 50 mm Hg and pulmonary venous flow velocity at 30 cm/s. Color and pulsed Doppler recordings were obtained with a VingMed 800 scanner interfaced with a computer facilitating digital analysis. RESULTS: The decrease in the velocity time integral of pulmonary venous flow was more prominent for any given volume of mitral regurgitation at higher left atrial pressure. When the mitral regurgitant jet was directed toward the pulmonary vein, a more prominent decrease in the velocity time integral was seen, especially for severe mitral regurgitation (40 ml) with high left atrial pressure (95% vs. 55%, p < 0.001); and the time to peak deceleration of forward flow was significantly shorter (485 vs. 523 ms, respectively, p < 0.01). Also, two different types (laminar and turbulent) of reversed pulmonary venous flow were observed. CONCLUSIONS: Multiple factors, including jet direction, mitral regurgitant volume and left atrial pressure, determine the effect of mitral regurgitation on pulmonary venous flow velocity patterns.     

Comparison of transesophageal Doppler methods with angiography for evaluation of the severity of mitral regurgitation

Doppler evaluation of mitral regurgitation remains difficult; thus, a head-to-head comparison of the diagnostic accuracy of Doppler methods was undertaken. Fifty patients with native mitral regurgitation underwent multiplane transesophageal echocardiography within 5 days of catheterization. Angiographic grade of mitral regurgitation and, in 20 patients with grade II-IV regurgitation, invasively determined regurgitant stroke volume were compared with color Doppler area, regurgitant jet diameter, ratio of systolic to diastolic peak pulmonary venous flow velocities, and (based on the proximal convergence zone) maximal regurgitant flow rate and regurgitant orifice area. Rank correlation coefficients of angiographic grade with Doppler parameters were 0.61 for color jet area, -0.61 for pulmonary venous flow velocity ratio, 0.69 for color jet diameter, 0.79 for maximal regurgitant flow rate, and 0.78 for regurgitant orifice area (all P < .01). Convergence zone-based parameters also correlated best (r=0.73) with invasively determined regurgitant stroke volume. Receiver operating characteristic curve analysis confirmed higher diagnostic accuracy for proximal jet width and proximal convergence zone parameters than for color jet area or pulmonary venous flow velocity ratio. Proximal convergence zone parameters and proximal color jet diameter best distinguished severe from mild forms of mitral regurgitation.     

Transesophageal Doppler echocardiography assessment of mitral valve insufficiency: Comparison of jet area, pulmonary venous flow profile, proximal jet diameter, maximal regurgitation flow rate and regurgitation orifice area with angiography

In transesophageal echocardiography several methods have been used to grade mitral regurgitation. For a direct comparison of these techniques, 36 patients (60 +/- 13 years) with native mitral regurgitation underwent multiplane transesophageal echocardiography and angiography within 5 days. We compared the following measurements: 1) The maximal color jet area of mitral regurgitation, 2) the ratio of maximal systolic to diastolic pulmonary venous flow velocity in the left upper pulmonary vein, 3) the proximal jet width of mitral regurgitation, 4) the maximal regurgitant flow rate Qmax, measured by the proximal convergence method, 5) the regurgitant office area Areg, calculated by dividing Qmax by maximal regurgitant velocity obtained by continuous wave Doppler. RESULTS: The correlation between color jet area (r = 0.4; p < 0.05) or pulmonary venous flow (r = -0.3; p = n.s.) with angiographic severity of mitral regurgitation is low. The sensitivity of the retrospective best cut-off values is 69% (color jet area) and 83% (pulmonary venous flow). Using retrospective best cut-off values all patients with mitral regurgitation Sellers grade III and IV are correctly identified by a proximal jet width > or = 0.7 cm, Qmax > or = 300 ml/s or a Areg > or = 0.5 cm2 (sensitivity and specificity of 83-100%). Spearman's rank coefficient demonstrated a high correlation (r = 0.75-0.77; p < 0.001) between proximal jet width, Qmax and Areg and with angiographic severity. CONCLUSION: Multiplane transesophageal echocardiographic grading of mitral regurgitation by proximal jet width or proximal convergence zone shows comparably good results and is clearly superior to grading by color jet area or pulmonary venous flow, if adequate image quality is achieved.     

Color Doppler regurgitant jet area for evaluating eccentric mitral regurgitation: an animal study with quantified mitral regurgitation

OBJECTIVES: The purpose of the present study was to rigorously evaluate the accuracy of the color Doppler jet area planimetry method for quantifying chronic mitral regurgitation. BACKGROUND: Although the color Doppler jet area has been widely used clinically for evaluating the severity of mitral regurgitation, there have been no studies comparing the color jet area with a strictly quantifiable reference standard for determining regurgitant volume. METHODS: In six sheep with surgically produced chronic mitral regurgitation, 24 hemodynamically different states were obtained. Maximal color Doppler jet area for each state was obtained with a Vingmed 750. Image data were directly transferred in digital format to a microcomputer. Mitral regurgitation was quantified by the peak and mean regurgitant flow rates, regurgitant stroke volumes and regurgitant fractions determined using mitral and aortic electromagnetic flow probes. RESULTS: Mean regurgitant volumes varied from 0.19 to 2.4 liters/min (mean [+/- SD] 1.2 +/- 0.59), regurgitant stroke volumes from 1.8 to 29 ml/beat (mean 11 +/- 6.2), peak regurgitant volumes from 1.0 to 8.1 liters/min (mean 3.5 +/- 2.1) and regurgitant fractions from 8.0% to 54% (mean 29 +/- 12%). Twenty-two of 24 jets were eccentric. Simple linear regression analysis between maximal color jet areas and peak and mean regurgitant flow rates, regurgitant stroke volumes and regurgitant fractions showed correlation, with r = 0.68 (SEE 0.64 cm2), r = 0.63 (SEE 0.67 cm2), r = 0.63 (SEE 0.67 cm2) and r = 0.58 (SEE 0.71 cm2), respectively. Univariate regression comparing regurgitant jet area with cardiac output, stroke volume, systolic left ventricular pressure, pressure gradient, left ventricular/left atrial pressure gradient, left atrial mean pressure, left atrial v wave pressure, systemic vascular resistance and maximal jet velocity showed poor correlation (0.08 < r < 0.53, SEE > 0.76 cm2). CONCLUSIONS: This study demonstrates that color Doppler jet area has limited use for evaluating the severity of mitral regurgitation with eccentric jets.     

Biplane transesophageal color-flow Doppler imaging in assessing severity of mitral regurgitation: influence of hemodynamic circumstances and mechanism of regurgitation

OBJECTIVE: To determine the value of biplane transesophageal echocardiography in the assessment of severity of mitral regurgitation compared with left ventricular angiography. DESIGN: Prospective study of consecutive patients. SETTING: Two university hospitals, one community hospital. PARTICIPANTS: Thirty-seven patients with angiographically proven mitral regurgitation. INTERVENTION: Transthoracic and biplane transesophageal echocardiography. In 19 patients, transesophageal echocardiography was performed during general anesthesia. MEASUREMENTS AND MAIN RESULTS: The largest mitral regurgitation jet area and longest jet as obtained with Doppler color-flow mapping from transthoracic and biplane transesophageal echocardiography and pulsed-Doppler pulmonary venous flow characteristics. Sensitivity and 100-minus-specificity were plotted to constitute receiver operating characteristics (ROC) curves. Areas under ROC curve for transverse, longitudinal, and biplane jet area were 0.77, 0.75, and 0.81, and for jet length, 0.82, 0.84, and 0.88, respectively; this was for biplane jet area in conscious patients; 0.99 compared with 0.72 in anesthetized patients (p < 0.05). CONCLUSIONS: Biplane measurements identified severe mitral regurgitation slightly more reliably than the transverse or longitudinal measurements alone. In conscious patients, jet area was an excellent test for estimating severity of mitral regurgitation. In anesthetized patients, a combination of biplane jet area and length and of systolic pulmonary venous flow reversal accurately predicted angiographic severity of mitral regurgitation. In anesthetized patients, the optimal cut-off value for jet area to distinguish between moderate and severe mitral regurgitation was lower than in conscious patients. In the total population, regardless of hemodynamic and technical variations, a combination of biplane jet area and length and of systolic pulmonary venous flow reversal accurately predicted the severity of mitral regurgitation.     

Effect of transcriptional regulatory sequences on autonomous replication of plasmids in transient mammalian systems

BACKGROUND AND AIMS OF THE STUDY: Most studies on mitral regurgitation have focused on evaluating the regurgitant volume. The effects of mitral regurgitation and its associated cardiac workload on left ventricular function and mechanics may be equally important both in assessing the impact of regurgitation as well as in planning and evaluating therapy. The present study was undertaken to investigate the interrelationships of the regurgitant volume, hemodynamics and left ventricular work in an experimental animal model of chronic mitral regurgitation in which the regurgitant volume could be measured directly with electromagnetic flow probes. METHODS: A total of 21 hemodynamic states were studied in six sheep with surgically created mitral regurgitation. Regurgitant flow rates were obtained from electromagnetic flow meters. Left ventricular and atrial pressures were recorded using high-fidelity catheters. Regurgitant jet velocity was recorded by continuous wave Doppler. Left ventricular stroke work and energy losses due to the regurgitation were calculated. RESULTS: There was a close correlation between left ventricular stroke work and both jet energy and left atrial systolic pressure rise (r = 0.81, p = 0.0001 and r = 0.92, p = 0.0001, respectively). A moderate correlation to the regurgitant volume was found (r = 0.52, p = 0.01). CONCLUSIONS: The regurgitant volume itself is only one of the determinants of left ventricular stroke work in mitral regurgitation. Other factors such as left atrial mechanical properties and the regurgitant kinetic jet energy are at least as important for assessing cardiac work in patients with mitral regurgitation.     

Mechanism of dynamic regurgitant orifice area variation in functional mitral regurgitation: physiologic insights from the proximal flow convergence technique

OBJECTIVES: We used the Doppler proximal flow convergence technique as a physiologic tool to explore the effects of the time courses of mitral annular area and transmitral pressure on dynamic changes in regurgitant orifice area. BACKGROUND: In functional mitral regurgitation (MR), regurgitant flow rate and orifice area display a unique pattern, with peaks in early and late systole and a midsystolic decrease. Phasic changes in both mitral annular area and the transmitral pressure acting to close the leaflets, which equals left ventricular-left atrial pressure, have been proposed to explain this dynamic pattern. METHODS: In 30 patients with functional MR, regurgitant orifice area was obtained as flow (from M-mode proximal flow convergence traces) divided by orifice velocity (v) from the continuous wave Doppler trace of MR, transmitral pressure as 4v(2), and mitral annular area from two apical diameters. RESULTS: All patients had midsystolic decreases in regurgitant orifice area that mirrored increases in transmitral pressure, while mitral annular area changed more gradually. By stepwise multiple regression analysis, both mitral annular area and transmitral pressure significantly affected regurgitant orifice area; however, transmitral pressure made a stronger contribution (r2 = 0.441) than mitral annular area (added r2 = 0.008). Similarly, the rate of change of regurgitant orifice area more strongly related to that of transmitral pressure (r2 = 0.638) than to that of mitral annular area (added r2 = 0.003). A similar regurgitant orifice area time course was observed in four patients with fixed mitral annuli due to Carpentier ring insertion. CONCLUSIONS: In summary, the time course and rate of change of regurgitant orifice area in patients with functional MR are predominantly determined by dynamic changes in the transmitral pressure acting to close the valve. Thus, although mitral annular area helps determine the potential for MR, transmitral pressure appears important in driving the leaflets toward closure, and would be of value to consider in interventions aimed at reducing the severity of MR.     

Transesophageal echocardiography in mitral prosthesis dysfunction: usefulness and limitations in the evaluation of mitral insufficiency

This study was performed to test the usefulness of transesophageal echocardiography in the diagnosis and assessment of pathological mitral regurgitation in patients with mitral valve prostheses. Doppler color flow imaging by transesophageal echocardiography was compared to the transthoracic echocardiography and angiographic and surgical assessment. We analyzed the influence of the spatial configuration of the jet on the semiquantitative assessment of mitral regurgitation. We studied 71 patients with prostheses in mitral position which were submitted for transesophageal echocardiography examination. 51 of these patients were found to have a pathological prosthetic regurgitation that was confirmed in 21 cases by left ventriculography and in 4 during cardiac surgery. Transesophageal echocardiography Doppler color flow imaging identified a regurgitant jet in 31 patients (60.7%). There was complete agreement with the quantitative assessment of regurgitation by angiography or surgery in 36% of the cases. All patients with prosthetic insufficiency observed by angiography or during cardiac surgery were confirmed by transesophageal echocardiography. Complete agreement in grade of severity by transthoracic echocardiography was found in 84% of cases. There was a difference in grade of severity of mitral regurgitation in only 4 patients. Regurgitant jets were classified by transesophageal echocardiography color Doppler in two groups: free jets and impinging wall jets. 21 cases presented a free jet and 31 excentrically directed impinging wall jet of mitral regurgitation. There was complete agreement with hemodynamic assessment of severity in all patients with regurgitant free jets (11/11). In presence of jet wall there was understimation of mitral regurgitation in 28.5% (4/13).(ABSTRACT TRUNCATED AT 250 WORDS)     

A transesophageal color-coded pulsed Doppler echocardiographic study of the spatial distribution of mitral regurgitation jets

OBJECTIVE: Transesophageal echocardiographic analysis of color Doppler characteristics of mitral valvular regurgitation jets. DESIGN: Transesophageal echocardiographic prospective study. SETTING: Ambulatory patients referred to Echocardiographic Laboratory of Gregorio Mara?on General Hospital, Madrid, Spain. MATERIAL AND METHODS: We studied a group of 100 consecutive patients with mitral regurgitation diagnosis. In each patient we calculated the degree of severity, percentage of wall intersection, maximal traced area, axis direction, atrial depth, maximal transversal diameter, perimeter and angle of the mitral regurgitation jet. We divided the entire population in three different groups according to the jet direction in central (CJ), eccentric (EJ) and wall jets (WJ). MAIN RESULTS: The direction of the mitral regurgitation jet was central in 49%, eccentric in 33% and impinging the left atrial wall in 18%. The mitral regurgitation jet angle was in the CJ 80 +/- 11 degrees, EJ 33 +/- 10 degrees and WJ 6 +/- 7 degrees. Maximal mitral regurgitant traced area in CJ was 732 +/- 104 mm2, EJ was 593 +/- 110 mm2 and WJ was 267 +/- 80 mm2. Maximal regurgitant jet depth in CJ was 36 +/- 17 mm, EJ 30 +/- 15 mm and WJ 49 +/- 14 mm. The perimeter of the mitral regurgitation jet in the CJ was 87 +/- 22 mm, EJ was 68 +/- 22 mm and WJ was 92 +/- 30 mm. CONCLUSIONS: Color Doppler quantification criteria are not useful in all patients with mitral regurgitation jets. The presence of atrial walls close to the mitral regurgitation jet area is an important factor in the mitral regurgitation color Doppler evaluation.     

Color flow imaging compared with quantitative Doppler assessment of severity of mitral regurgitation: influence of eccentricity of jet and mechanism of regurgitation

OBJECTIVES: To determine the influence of jet eccentricity and mechanism of mitral regurgitation, we examined 1) the relation between jet extent and severity of mitral regurgitation, and 2) the use of Doppler color flow imaging for quantitation of mitral regurgitation. BACKGROUND: Doppler color flow imaging is widely used to assess mitral regurgitation. However, whether, how and in which subgroups it can quantify regurgitation remain controversial. METHODS: In 80 patients with mitral regurgitation, results of color flow Doppler studies obtained in two orthogonal apical views were prospectively compared with quantitative Doppler measurement of the regurgitant volume and the regurgitant fraction. Comparisons were made according to the eccentricity of the jet (group 1 eccentric jets, n = 29; group 2 central jets, n = 51); group 2 was subdivided according to the mechanism of mitral regurgitation (group 2a organic, n = 27; group 2b ischemic or functional, n = 24). RESULTS: Globally, weak correlations were found between regurgitant volume and jet area (r = 0.57) and regurgitant fraction and jet area/left atrial area ratio (r = 0.65). Groups 1 and 2 showed a correlation between regurgitant volume and jet area (r = 0.68 and r = 0.65, respectively, p < 0.0001), but the slope was steeper in group 2 than in group 1 (0.22 vs. 0.06, p < 0.0001). The same jet area corresponded to more severe regurgitation in group 1 than in group 2 (jet > or = 8 cm2, regurgitant volume 113 +/- 55 vs. 43 +/- 21 ml, p < 0.0001). Similarly, for comparable regurgitant volumes (24 +/- 22 vs. 29 +/- 11 ml, p = NS), group 2a had a smaller jet area than did group 2b (5.3 +/- 6 vs. 9.6 +/- 6 cm2, p < 0.02). Quantitation of regurgitation by Doppler color flow imaging was unreliable in group 1; in group 2b, the regression line between regurgitant fraction and jet area/left atrial area ratio was close to the identity line. CONCLUSIONS: Mitral regurgitant jet eccentricity and mechanism influence jet extent. The same regurgitant volume produces smaller jet areas for eccentric compared with central jets and for central organic compared with ischemic or functional regurgitation. Quantitation of regurgitation using Doppler color flow imaging is possible in ischemic or functional regurgitation but inappropriate in eccentric jets, where quantitative Doppler study should be recommended.     

Understanding continuous-wave Doppler signal intensity as a measure of regurgitant severity

Continuous-wave Doppler signal intensity is commonly expected to reflect the severity of mitral regurgitation. Physical principles predict that alignment of the imaging beam, flow velocity, and turbulence can also be important or even dominant determinants of continuous-wave Doppler signal intensity. The reliability of tracking regurgitant severity with continuous-wave Doppler signal intensity was assessed in vitro with varying volume, velocity, turbulence, and beam alignment. The conditions wherein continuous-wave Doppler signal intensity increased with regurgitant volume were specific but poorly predictable combinations of orifice size, flow volume, and perfect beam alignment. Under other conditions flow velocity and turbulence effects dominated, and continuous-wave Doppler signal intensity did not reflect changing regurgitant volume. Continuous-wave Doppler signal intensity-based impressions of regurgitant severity may be unreliable and even misleading under some circumstances.     

The rate of force generation by the myocardium is not influenced by afterload

The influence of afterload on the rate of force generation by the myocardium was investigated using two types of preparations: the in situ dog heart (dP/dt) and isolated papillary muscle of rats (dT/dt). Thirteen anesthetized, mechanically ventilated and thoracotomized dogs were submitted to pharmacological autonomic blockade (3.0 mg/kg oxprenolol plus 0.5 mg/kg atropine). A reservoir connected to the left atrium permitted the control of left ventricular end-diastolic pressure (LVEDP). A mechanical constriction of the descending thoracic aorta allowed to increase the systolic pressure in two steps of 20 mmHg (conditions H1 and H2) above control values (condition C). After arterial pressure elevations (systolic pressure C: 119 +/- 8.1; H1: 142 +/- 7.9; H2: 166 +/- 7.7 mmHg; P < 0.01), there were no significant differences in heart rate (C: 125 +/- 13.9; H1: 125 +/- 13.5; H2: 123 +/- 14.1 bpm; P > 0.05) or LVEDP (C: 6.2 +/- 2.48; H1: 6.3 +/- 2.43; H2: 6.1 +/- 2.51 mmHg; P > 0.05). The values of dP/dt did not change after each elevation of arterial pressure (C: 3,068 +/- 1,057; H1: 3,112 +/- 996; H2: 3,086 +/- 980 mmHg/s; P > 0.05). In isolated rat papillary muscle, an afterload corresponding to 50% and 75% of the maximal developed tension did not alter the values of the maximum rate of tension development (100%: 78 +/- 13; 75%: 80 +/- 13; 50%: 79 +/- 11 g mm-2 s-1, P > 0.05). The results show that the rise in afterload per se does not cause changes in dP/dt or dT/dt.     

An integrated approach to the quantification of aortic regurgitation by Doppler echocardiography

BACKGROUND: Although different Doppler methods have been proposed for the quantification of aortic regurgitation, no study has prospectively compared these methods with each other and their correlation with angiography. The aim of this study was to prospectively analyze the usefulness of different Doppler echocardiography parameters by testing all such parameters in each patient. METHODS: Fifty-one patients with aortic regurgitation underwent 2-dimensional and Doppler echocardiographic studies and catheterization. The following Doppler indexes were analyzed and compared with aortography. Color Doppler: (1) jet color height/left ventricular outflow tract height in parasternal long-axis view, and (2) jet color area/left ventricular outflow tract area in short-axis view. Continuous Doppler: (3) regurgitant flow pressure half-time, (4) regurgitant flow time velocity integral (in centimeters), and (5) regurgitant flow time velocity integral (in centimeters)/diastolic period (in milliseconds). Pulsed Doppler in thoracic and abdominal aorta: (6) time velocity integral of diastolic reverse flow (in centimeters), (7) time velocity integral of systolic anterograde flow/integral of diastolic reverse flow, (8) (time velocity integral of diastolic reverse flow/diastolic period) x 100, and (9) diastolic reverse flow duration/diastolic period (as a percentage). We compared these parameters with severity of regurgitation measured by angiography and classified as mild, moderate, or severe. RESULTS: The most useful parameters were (1) jet color height/left ventricular outflow tract height (correctly classified 42 of 49 patients), (2) (time velocity integral of diastolic reverse flow/diastolic period) x 100 in the thoracic aorta (correctly classified 41 of 46 patients), and (3) (time velocity integral of diastolic reverse flow/diastolic period) x 100 in the abdominal aorta (correctly classified 42 of 49 patients). Sequential integration of these 3 parameters correctly classified 96% of patients (44 of 46 patients) and was achieved in 90% of cases. CONCLUSION: An integrated combination of several Doppler parameters can quickly and accurately classify the degree of aortic regurgitation as determined by angiography.     

Isradipine lowers human arterial low density lipoprotein retention in vivo

An 84-year-old woman was admitted to our hospital because of left heart failure of acute onset. Transthoracic echocardiography showed diffuse hypertrophy of the normal sized hyperkinetic left ventricle and chordae-like fluttering echoes attached to the mitral valve with severe mitral regurgitation signals. Mosaic flow signals were seen at the left ventricular outflow tract, but the velocity could not be measured. Emergent transesophageal echocardiography detected no obvious mitral valve prolapse. Cardiac catheterization showed greater than 100 mmHg pressure gradient between the left ventricle and femoral artery. Pressures in the femoral artery and pulmonary capillary wedge changed reciprocally in the intensive care unit; a bisferient narrow pulse pressure of the femoral artery was associated with increased v wave of the pulmonary capillary wedge pressure, and a wide pulse pressure of the femoral artery with absent v wave of the pulmonary capillary wedge pressure. Pressure monitoring in the intensive care unit, catheterization laboratory and transesophageal echocardiography were useful to understand the pathophysiology of the patient.     

Stress-induced left ventricular outflow tract obstruction: a potential cause of dyspnea in the elderly

OBJECTIVES: We sought to identify the pattern of disturbed left ventricular physiology associated with symptom development in elderly patients with effort-induced breathlessness. BACKGROUND: Limitation of exercise tolerance by dyspnea is common in the elderly and has been ascribed to diastolic dysfunction when left ventricular cavity size and systolic function appear normal. METHODS: Dobutamine stress echocardiography was used in 30 patients (mean [+/-SD] age 70 +/- 12 years; 21 women, 9 men) with exertional dyspnea and negative exercise test results, and the values were compared with those in 15 control subjects. RESULTS: Before stress, left ventricular end-diastolic and end-systolic dimensions were reduced, fractional shortening was increased, and the basal septum was thickened (2.3 +/- 0.5 vs. 1.4 +/- 0.2 cm, p < 0.001, vs. control subjects) in the patients, but posterior wall thickness did not differ from that in control subjects. Left ventricular outflow tract diameter, measured as systolic mitral leaflet septal distance, was significantly reduced (13 +/- 4.5 vs. 18 +/- 2 mm, p < 0.001). Isovolumetric relaxation time was prolonged, and peak left ventricular minor axis lengthening rate was reduced (8.1 +/- 3.5 vs. 10.4 +/- 2.6 cm/s, p < 0.05), suggesting diastolic dysfunction. Transmitral velocities and the E/A ratio did not differ significantly. At peak stress, heart rate increased from 66 +/- 8 to 115 +/- 20 beats/min in the control subjects, but blood pressure did not change. Transmitral A wave velocity increased, but the E/A ratio did not change. Left ventricular outflow tract velocity increased from 0.8 +/- 0.1 to 2.0 +/- 0.2 m/s, and mitral leaflet septal distance decreased from 18 +/- 2 to 14 +/- 3 mm, p < 0.001. In the patients, heart rate rose from 80 +/- 12 to 132 +/- 26 beats/min and systolic blood pressure from 143 +/- 22 to 170 +/- 14 mm Hg (p < 0.001 for each), but left ventricular dimensions did not change. Peak left ventricular outflow tract velocity increased from 1.5 +/- 0.5 m/s (at rest) to 4.2 +/- 1.2 m/s; mitral leaflet septal distance fell from 13 +/- 4.5 to 2.2 +/- 1.9 mm (p < 0.001); and systolic anterior motion of mitral valve appeared in 24 patients (80%) but in none of the control subjects (p < 0.001). Measurements of diastolic function did not change. All patients developed dyspnea at peak stress, but none developed a new wall motion abnormality or mitral regurgitation. CONCLUSIONS: Although our patients fulfilled the criteria for "diastolic heart failure," diastolic dysfunction was not aggravated by pharmacologic stress. Instead, high velocities appeared in the left ventricular outflow tract and were associated with basal septal hypertrophy and systolic anterior motion of the mitral valve. Their appearance correlated closely with the development of symptoms, suggesting a potential causative link.     

Assessment of mitral regurgitation severity by Doppler color flow mapping of the vena contracta

BACKGROUND: Although Doppler color flow mapping is widely used to assess the severity of mitral regurgitation (MR), a simple, accurate, and quantitative marker of MR by color flow mapping remains elusive. We hypothesized that vena contracta width by color flow mapping would accurately predict the severity of MR. METHODS AND RESULTS: We studied 80 patients with MR. Vena contracta width was measured in multiple views with zoom mode and nonstandard angulation to optimize its visualization. Flow volumes across the left ventricular outflow tract and mitral annulus were calculated by pulsed-Doppler technique to determine regurgitant volume. Effective regurgitant orifice area was calculated by dividing the regurgitant volume by the continuous-wave Doppler velocity-time integral of the MR jet. The cause of MR was ischemia in 24, dilated cardiomyopathy in 34 mitral valve prolapse in 12, endocarditis in 2, rheumatic disease in 2, mitral annular calcification in 1, and uncertain in 5. Regurgitant volumes ranged from 2 to 191 mL. Regurgitant orifice area ranged from 0.01 to 1.47 cm2. Single-plane vena contracta width from the parasternal long-axis view correlated well with regurgitant volume (r = .85, SEE = 20 mL) and regurgitant orifice area (r = .86, SEE = 0.15 cm2). Biplane vena contracta width from apical views correlated well with regurgitant volume (r = .85, SEE = 19 mL) and regurgitant orifice area (r = .88, SEE = 0.14 cm2). A biplane vena contracta width > or = 0.5 cm was always associated with a regurgitant volume > 60 mL and a regurgitant orifice area > 0.4 cm2. A biplane vena contracta width < or = 0.3 cm predicted a regurgitant volume < 60 mL and a regurgitant orifice area < 0.4 cm2 in 24 of 29 patients. No other parameter, including jet area, left atrial size, pulmonary flow reversal, or semiquantitative MR grade, correlated significantly with regurgitant volume or regurgitant orifice area in a multivariate analysis. CONCLUSIONS: Our results demonstrate that careful color flow mapping of the vena contracta of the MR jet provides a simple quantitative assessment of MR that correlates well with quantitative Doppler techniques.     

In situ hybridization for the detection of telomerase RNA in the progression from Barrett''s esophagus to esophageal adenocarcinoma

AIMS: To compare the value of the proximal flow convergence method and the jet area method for the determination of the severity of tricuspid regurgitation. METHODS AND RESULTS: The proximal isovelocity surface area radius and the jet area/length were measured in 71 consecutive patients with angiographically graded (grade 0/I-III) tricuspid regurgitation. Rank correlation coefficients with the angiographic grade were 0.71 (P < 0.001) for the proximal isovelocity surface area radius (aliasing border of 28 cm.s-1), 0.66 (P < 0.001) for the jet area, and 0.63 (P < 0.001) for the jet length. The proximal isovelocity surface area radius was significantly correlated with the jet area/length (correlation coefficients 0.82/0.77, P < 0.001). Correct differentiation between mild to moderate (grade I-II) and severe (grade III) tricuspid regurgitation was achieved in 62 of 71 patients (87%) by means of the proximal isovelocity surface area radius, in 61 of 71 (86%) by the jet area, and in 62 of 71 (87%) by the jet length. Grade III tricuspid regurgitation was not identified in five of 21 patients (24%) by means of the proximal isovelocity surface area radius, in six of 21 (29%) by the jet area, and in seven of 21 (33%) by the jet length. CONCLUSION: The flow convergence method and the jet area method are of similar value for the determination of the severity of tricuspid regurgitation. Both methods differentiated mild to moderate from severe tricuspid regurgitation in most patients. However, underestimation of severe tricuspid regurgitation in 20-30% of the cases represents a serious limitation of both methods.     

Aortic blood momentum--the more the better for the ejecting heart in vivo?

OBJECTIVES: The aim of the present study was to test two hypotheses: (1) the momentum of the blood flowing out of the left ventricle toward the aorta (inertia force) plays an important role in the initiation of decay and the maximum rate of decay (peak (-dP/dt)) of left ventricular pressure (P); (2) a normal heart itself generates the inertia force which enhances its function. METHODS: The contribution of the inertia force to (-dP/dt) was theoretically given as rho c alpha, where rho is the blood density, c the pulse wave velocity, and alpha the deceleration rate of aortic blood flow. The correlations of peak (-dP/dt) with rho c alpha and with the time constant (tau) of the pressure decay during isovolumic relaxation, which was considered to represent myocardial relaxation characteristics, were compared in seven dogs. We developed a method of grading the strength of the inertia force, using the phase loop of left ventricular pressure (dP/dt vs. P relation). The method was applied to the records of 25 patients with ischemic heart disease, from which high fidelity left ventricular pressure recordings were available. RESULTS: The correlation of peak (-dP/dt) with rho c alpha was much higher than with tau (0.75 vs. -0.46). 16 of the 25 patients showed evidence of the inertia force. However, other patients showed no inertia force. The strength of the inertia force showed a significant (P < 0.05) correlation with left ventricular end-diastolic pressure (r = -0.46), cardiac index (r = 0.62), stroke volume index (r = 0.69), ejection fraction (r = 0.46), and peak (-dP/dt) (r = 0.56). CONCLUSION: The inertia force of late systolic aortic flow contributed to ventricular relaxation in the normal heart.     

Noninvasive estimation of regurgitant flow rate and volume in patients with mitral regurgitation by Doppler color mapping of accelerating flow field

OBJECTIVES: This study was designed to examine the accuracy of proximal accelerating flow calculations in estimating regurgitant flow rate or volume in patients with different types of mitral valve disease. BACKGROUND: Flow acceleration proximal to a regurgitant orifice, observed with Doppler color flow mapping, is constituted by isovelocity surfaces centered at the orifice. By conservation of mass, the flow rate through each isovelocity surface equals the flow rate through the regurgitant orifice. METHODS: Forty-six adults with mitral regurgitation of angiographic grades I to IV were studied. The proximal accelerating flow rate (Q) was calculated by: Q = 2 pi r2.Vn, where pi r2 is the area of the hemisphere and Vn is the Nyquist velocity. Radius of the hemisphere (r) was measured from two-dimensional or M-mode Doppler color recording. From the M-mode color study, integration of accelerating flow rate throughout systole yielded stroke accelerating flow volume and mean flow rate. Mitral regurgitant flow rate and stroke regurgitant volume were measured by using a combination of pulsed wave Doppler and two-dimensional echocardiographic measurements of aortic forward flow and mitral inflow. RESULTS: The proximal accelerating flow region was observed in 42 of 46 patients. Maximal accelerating flow measured from either two-dimensional (372 +/- 389 ml/s) or M-mode (406 +/- 421 ml/s) Doppler color study tended to overestimate the mean regurgitant flow rate (306 +/- 253 ml/s, p < 0.05). Mean Doppler accelerating flow rate correlated well with mean regurgitant flow rate (r = 0.95, p < 0.001), although there was a tendency toward slight overestimation of mean regurgitant flow by mean accelerating flow in severe mitral regurgitation. However, there was no significant difference between the mean accelerating flow rate (318 +/- 304 ml/s) and the mean regurgitant flow rate (306 +/- 253 ml/s, p = NS) for all patients. A similar relation was found between accelerating flow stroke volume (78.27 +/- 62.72 ml) and regurgitant flow stroke volume (76.06 +/- 59.76 ml) (r = 0.95, p < 0.001). The etiology of mitral regurgitation did not appear to affect the relation between accelerating flow and regurgitant flow. CONCLUSIONS: Proximal accelerating flow rate calculated by the hemispheric model of the isovelocity surface was applicable and accurate in most patients with mitral regurgitation of a variety of causes. There was slight overestimation of regurgitant flow rate by accelerating flow rate when the regurgitant lesion was more severe.     

Relation between mitral orifice surface area and extent of hemodynamic disorder of the pulmonary circulation in patients with mitral stenosis

Mitral annulus and valves form the mitral orifice area with the size between 4.0-6.0 cm2. Every area which is smaller than this, represents mitral stenosis. As a consequence of mitral stenosis hemodynamic gradients occur over the mitral orifice with circulation disturbances below and above the stenotic mitral valve. The size of transmitral gradient is important in the evaluation of functional or/and structural changes in the blood vessels of pulmonary circulation. This investigation included 40 patients with mitral stenosis (or accompanying minimal mitral regurgitation). All patients underwent echocardiographic examination: area of the mitral orifice was determined and hemodynamic procedure with the left and right heart catheterization was performed. The following hemodynamic parameters were measured: mean capillary wedge pressure, left ventricular filling pressure, left ventricular mean diastolic pressure, mean pulmonary artery pressure. According to these parameters resistance in the pulmonary circulation was measured. The size of the mitral orifice was determined according to oximetry blood analyses and hemodynamic parameters. All patients were divided into 4 groups: minimal (2.5-4.0 cm2), mild (1.5-2.5 cm2), moderate (1.0-1.5 cm2) and severe mitral stenosis (1.0 cm2). The comparison of echocardiographic and hemodynamic parameters revealed a high and positive correlation between the area of mitral orifice. There was also a negative and moderate correlation between the values of stenotic mitral orifice area and total pulmonary resistance, i.e. in all patients with severe mitral stenosis there was an increased pulmonary arteriolar resistance. CONCLUSION: Noninvasive echocardiographic method is valid in the evaluation of stenotic mitral valve area. In the evaluation of hemodynamic parameters in the pulmonary circulation the index of arteriolar pulmonary systemic vascular resistance is very important. In all patients with the area of stenotic mitral orifice 1.0 cm2, there are functional or pathomorphologic changes in the pulmonary circulation of the blood vessel wall.