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Sixty-six consecutive patients without left ventricular volume overload, significant arrhythmia or significant pericardial effusion were examined by M-mode echocardiography immediately before diagnostic left- and right-heart catheterization. Using various echocardiographic measurements, left ventricular stroke volume (SV) was calculated according to eight different echocardiographic formulas (SVE) that have been proposed previously. At catheterization SV was also determined by thermodilution (SVT) and by single-plane left ventricular cineangiography in the right anterior oblique projection (SVA). When comparing SVE with SVT, the four formulas developed to calculate mitral or aortic flow failed (r = 0.10 to 0.54). As expected, poor correlations (r = 0.22 to 0.47) were also found when formulas used to calculate ventricular volumes from the ventricular diameter or SV from the change in diameter (left ventricular formulas) were used in coronary patients with grossly asymmetrical ventricular contraction patterns. When the use of the left ventricular formulas was confined to patients with symmetrical or almost symmetrical contraction, two formulas yielded favorable correlations of r = 0.84, SEE = 12.7 ml and r = 0.86, SEE = 12.2 ml, respectively. These correlations were comparable to the correlation between our two invasive reference techniques (r = 0.81; SEE = 12.2 ml). The comparison between SVE and SVA confirmed the results of the thermodilution study, though the correlations were generally weaker. We conclude that the formula of Teichholz et al., which was the best of all tested formulas, may be used to obtain a clinically useful estimate of SV in patients in whom symmetrical or almost symmetrical left ventricular contraction can be anticipated.
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PMID:Comparative value of eight M-mode echocardiographic formulas for determining left ventricular stroke volume. A correlative study with thermodilution and left ventricular single-plane cineangiography. 49 56

A formula was derived for calculating mitral valve stroke volume (MVSV) using the rate of mitral valve (MV) opening (DE slope on the MV echogram), the vertical disease between the mitral leaflet echoes early in diastole (EE), the electrocardiographic PR interval and heart rate. The formula was tested prospectively on 80 consecutive patients from whom 95 simultaneous MV echograms and either thermodilution (45) or Fick (50) cardiac outputs were obtained. Sixteen patients were normal; 54 had coronary artery disease; three had cardiomyopathy; and seven had nonrheumatic mitral regurgitation (MR). Linear regression for stroke volume was r = 0.90, SEE +/- 6, and for cardiac output r = 0.83, SEE +/- 0.5 liter for the 73 patients without MR. The presence or absence of ventricular dyssynergy did not alter statistical findings. MVSV consistently overestimated forward stroke volume for the seven patients with MR. This study shows that the MV echogram provides an accurate, widely applicable method for calculating MVSV.
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PMID:Stroke volume calculated from the mitral valve echogram in patients with and without ventricular dyssynergy. 64 75

Twenty-four patients with proven coronary artery disease and abnormally-contracting segments were studied by both echocardiography and biplane angiographic techniques. Comparison was made between the left ventricular biplane angiographic volumes and those obtained from echocardiographic measurements which were calculated from cubed function and regression equaltion methods. The percent abnormally contracting segment (ACS) was obtained from biplane left ventricular angiography and was calculated from the diastolic and systolic anteroposterior and lateral angiocardiograms. The angiographic end-diastolic volume correlated with that calculated from the echocardiographic dimensions with an r value of 0.865 and SEE of +/- 22.64 ml. The angiographic end-systolic volume and echo end-systolic volume did not correlate as well, with an r = 0.7063. The difference in stroke volume predicted by the diastolic and systolic echocardiographic dimensions and the actual stroke volume determined by Fick technique was related to the percent abnormally contracting segment of the left ventricle (r = 0.8967). The percent ACS could be estimated from echo and Fick stroke volume measurements by the cube function and regression equations. Echo ventricular volume determinations were analyzed for the cube function method and the regression equations of Fortuin et al. and Teichholz and coworkers, with the method of Fortuin et al. producing the most sensitive relationship: % ACS = 0.32 (SVecho - SVFick) % + 8.9%. The correlation coefficient for the estimate was 0.8967 with a SEE of +/- 4.78%. In patients with coronary artery disease and abnormally contracting segments, echocardiography can provide reliable measurements of left ventricular end-diastolic volume but estimates of end-systolic volume are less accurate. If mitral regurgitation or a ventricular aneurysm can be excluded, the difference in echocardiographic and forward stroke volume by an independent method is related to the angiographic and forward stroke volume by an independent method is related to the angiographic abnormally contracting segment, and this relationship permits estimation of the size of the abnormally, contracting segment.
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PMID:Relationship between echocardiography, cardiac output, and abnormally contracting segments in patients with ischemic heart disease. 115 76

After myocardial infarction (MI), left ventricular (LV) end-diastolic pressure (EDP) is higher than mean pulmonary artery wedge pressure because of powerful atrial contraction. To evaluate the significane of atrial contraction to left ventricular function we studied 10 control (C) patients without cardiac disease and 17 patients from three to six weeks after acute myocardial infarction. Cardiac catheterization with simultaneous left ventricular diastolic pressure (DP) and left ventricular cineangiograms were obtained. Left ventricular volumes and pressure were (mean +/- SD): (SEE ARTICLE). Although left ventricular stroke volume was lower in the patients with myocardial infarction than in the control subjects (46 versus 56 ml/m2), atrial contraction contributed more to left ventricular filling during diastole (which is the same as left ventricular stroke volume) in the patients with myocardial infarction than in the controls (16 versus 10 ml/m2). The average atrial contribution to left ventricular end-diastolic volume was 11.9 per cent (C), 15.4 per cent (MI); to left ventricular end-diastolic pressure 20 per cent (C), 38.7 per cent (MI); and to left ventricular stroke volume 21.7 per cent (C), 35.1 per cent (MI). Atrial contribution to left ventricular stroke volume was 56 per cent in patients with a cardiac index less than or equal to 2.0 liters/min/m2 and 31 per cent in those with a cardiac index greater than 2 liters/min/m2 (p less than 0.01). Atrial contraction contributed 35 per cent to left ventricular stroke volume in patients with normal end-diastolic volume and in those with increased end-diastolic volume and 10 per cent to end-diastolic volume in patients with increased end-diastolic volume (p less than 0.001). In patients with myocardial infarction, atrial contraction made a large contribution to left ventricular filling and stroke volume irrespective of the type of left ventricular functional derangement that was present. The "booster pump" function of the atrium cannot be ignored in assessing left ventricular performance.
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PMID:Left atrial transport function in myocardial infarction. Importance of its booster pump function. 120 36

Many observers remain sceptical with regards to the utilization of Doppler-echocardiographic measurements of intracardiac outputs for the quantification of shunts and regurgitations. In this context, we evaluated the feasibility and validity of measuring output at the level of the four cardiac valves in a population of 35 normal subjects (24 M, 12 F) aged from 23 to 37 years (mean +/- SD = 28 +/- 4). Measurement of stroke volume and output using predetermined criteria was possible in the aortic position in 35 (100%) subjects, in the mitral position in 34 (97%), in the pulmonary position in 20 (57%) and in the tricuspid position in 10 (29%). In 14 subjects (40%), measurement was possible at 2 sites, in 14 (40%) at 3 sites and in 7 (20%) at 4 sites. Inability to measure output was most often due to poor visualization of valvular annulus. There are excellent correlations between aortic stroke volume on the one hand and the mitral (r = 0.97, SEE = 3.41 cc), pulmonary (r = 0.97, SEE = 3.69 cc) and tricuspid (r = 0.96, SEE = 2.77 cc) stroke volumes respectively on the other. These results suggest that reliable measurements of output are feasible in a majority of cases in the aortic and mitral positions but to a much more limited extent in the pulmonary and tricuspid positions; given the small SEE's, they should be useful to quantitate shunts and regurgitations, when feasible.
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PMID:[Measurement of cardiac output by Doppler echocardiography at the 4 cardiac valves]. 141 68

A thermodilution catheter and computer system has been developed to measure right ventricular ejection fraction and volumes. To evaluate the performance of this method, the thermodilution system was evaluated in an in vitro pulsatile flow model. Thermodilution measurements of ejection fraction (EF), cardiac output (CO), stroke volume (SV), end-diastolic volume (EDV), and end-systolic volume (ESV) were compared with known values in a pulsatile flow bench. Thermodilution EF measurements correlated very well with the pulsatile flow model (r2 = 0.95, m [slope] = 0.85, SEE = 4.0 EFU). Thermodilution CO and SV were highly predictive of actual pulsatile flow (r2 = 0.99, m = 0.99, SEE = 187 ml/min and r2 = 0.98, m = 0.96, SEE = 2.5 ml, respectively). Thermodilution end-diastolic and end-systolic volume measurements resulted in low mean eror, -1.8% and 0.6%, respectively. The standard deviations of the error for EDV and ESV were 11.0% and 16.4%. The thermodilution measurements were repeatable, with CO, SV, and EF coefficients of variation of 3.2%, 3.3%, and 4.7%, respectively. EDV and ESV were slightly more variable, with coefficients of variation of 5.5% and 7.2%, respectively.
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PMID:In vitro validation of a thermodilution right ventricular ejection fraction method. 153 57

Right ventricular end-diastolic and stroke volumes were calculated from orthogonal subcostal echocardiographic images in 24 neonates (mean weight +/- SD 3.4 +/- 0.4 kg) with pulmonary atresia (n = 18) or critical pulmonary stenosis (n = 6) and intact ventricular septum before and at an average of 5 days and then 19 days after pulmonary valvotomy. The preoperative echocardiographic volume determinations were compared with the respective angiographic determinations. In addition, the endocardial area outlines of the left and right ventricles were obtained by planimetry from an end-diastolic frame taken in the apical four-chamber view. End-diastolic and stroke volumes calculated by the echocardiographic method (y) correlated closely with those calculated by the angiographic method (x); the regression equations were y = 1.02 x -0.13 (r = 0.95, SEE +/- 0.45 ml) and y = 1.16 x -0.15 (r = 0.89, SEE +/- 0.38 ml), respectively. All except one infant had right ventricular hypoplasia before valvotomy with an end-diastolic volume of 16.6 +/- 6.4 ml/m2 (44.5 +/- 17.3% of normal). Right to left ventricular area ratio was 0.56 +/- 0.09 (normal 0.95). Five days after valvotomy, right ventricular end-diastolic volume decreased to 10.6 +/- 4.6 ml/m2 (p less than 0.05) and stroke volume decreased from 8.3 +/- 3.5 to 5.5 +/- 2.8 ml/m2 (p less than 0.05). Nineteen days after valvotomy, right ventricular end-diastolic volume and right to left ventricular area ratio had increased to their respective preoperative values; right ventricular stroke volume had increased further to 10.4 +/- 3.9 ml/m2 (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Changes of right ventricular size and function in neonates after valvotomy for pulmonary atresia or critical pulmonary stenosis and intact ventricular septum. 155 91

Based on the phase difference method as described by Nayler et al. we developed a gradient-echo sequence, which refocuses flow related phase shifts even for infants with their higher peak velocity, higher acceleration and faster heart rates. A repetition time (TR) of 15 ms provides a high temporal resolution for dynamic studies. Modification of the flow-rephasing gradient-echo sequence in slice select direction leads to a defined phase shift and the resultant phase difference images allow blood flow measurements in the great arteries and the calculation of blood volume per heart cycle (flow volume) to assess left and right ventricular stroke volume. This can also be achieved by calculation of the ventricular volume from contiguous slices of the whole heart, but, this in excessive measuring times. Both methods were applied in 6 examinations of children with congenital heart diseases (1 pulmonary sling, 1 coarctation of the aorta, 1 ventricular septal defect, 3 atrial septal defects). The age of the patients ranged from 3 months to 13.4 years (mean age 4.9 years). The regression analyses of both methods show a high correlation for systemic flow (y = -0.98 + 1.08 x, r = 0.99, SEE = 2.59 ml) and for pulmonary flow (y = -1.40 + 0.96 x, r = 0.99, SEE = 4.70 ml). The comparison of flow calculated Qp:Qs ratio and chamber size calculated Qp:Qs ratio with data obtained by heart catheterization show also a regression line close to the line of identity (y = -0.01 + 1.04 x, r = 0.98, SEE = 0.15 and y = 0.28 + 0.96 x, r = 0.81, SEE = 0.47, respectively).
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PMID:Noninvasive blood flow measurement and quantification of shunt volume by cine magnetic resonance in congenital heart disease. Preliminary results. 159 9

To quantify valve area in mitral stenosis, a modified continuity equation method using continuous wave Doppler and thermodilution measurements was applied. In 14 patients with mitral stenosis and sinus rhythm (age: 49 +/- 11 years), transmitral flow velocity was recorded by continuous wave Doppler during right and left heart catheterization. Mitral valve area was calculated by three different methods: 1. According to the continuity equation, stroke volume (thermodilution technique) was divided by the registered time velocity integral of the mitral stenotic jet (continuous wave Doppler). 2. Mitral valve area was calculated by the pressure half-time method. 3. Simultaneous pulmonary capillary wedge and left ventricular pressure measurements were used for determination of mitral valve area according to the Gorlin formula. The mitral valve area determined by application of the continuity equation (y) showed a close correlation to the valve area calculated by the Gorlin equation (x): y = 0.73x + 0.12, SEE = 0.11 cm2, r = 0.88, P less than 0.001. In contrast, the correlation between mitral valve area determined by pressure half-time (y) and the Gorlin formula (x) was not as good: y = 0.77x + 0.11, SEE = 0.26 cm2, r = 0.65, P less than 0.05. Thus, the continuity equation method using combined continuous wave Doppler and thermodilution technique allows a valid determination of mitral valve area. In patients with mitral stenosis and sinus rhythm, this technique is superior to the noninvasive determination of mitral valve area by the conventional pressure half-time method.
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PMID:Value of a modified continuity equation method to quantify mitral valve area in patients with mitral stenosis and sinus rhythm. 179 98

The issuing flow rate of a jet, Q0, is given by Q0 = U0A, where U0 is the issuing velocity of the jet and A is the cross-sectional area of the orifice. However, measurement of A of a regurgitant jet in the cardiovascular system is difficult. On the assumption that the jet is 'free' and turbulent, the following relations apply between the diameter of the orifice D, the length of the core region of the jet L, the centerline velocity of the jet Uc(chi) at an arbitrary distance chi(greater than L) from the orifice, and U0:L = 6.8D and Uc(chi)/U0 = L/chi. From these equations we obtain Q0 = 0.017 (chi Uc(chi))2/U0. Pulsatile jets issuing into an aqueous glycerol bath through orifices with various diameters were studied. U0, chi and Uc(chi) were measured with a color Doppler system. There was a good linear correlation between the peak flow rates estimated from the above equation and those measured with a flowmeter irrespective of the diameter of orifices (y = 0.93 chi + 3.8, r = 0.95, SEE = 6.6 ml/s). Assuming that the flow rate waveform is similar to the issuing velocity waveform, we estimated the issuing volume per stroke by integrating the issuing velocity. There was a good linear correlation between the estimated issuing volume and the known stroke volume of the pump (y = 1.0 chi + 2.6, r = 0.92, SEE = 2.8 ml).
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PMID:A method of measuring the peak flow rate and the regurgitant volume of regurgitation based on the characteristics of turbulent free jets. 185 73

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