Calculation of the pulmonary to systemic flow ratio using echo-Doppler in septal defects--correlation with oximetry

OBJECTIVE: 1. local validation of a protocol of measurement of pulmonary to systemic flow ratio (QP/QS) by echo-Doppler in children with septal defects; 2. to assess continuous wave Doppler efficacy mainly in those patients where peak pulmonary flow velocity was beyond the Nyquist limit of pulsed Doppler. DESIGN: To correlate QP/QS ratio determined by echo-Doppler with that obtained by cardiac catheterization (oximetric method) performed within 48 hours, in children with isolated septal defects. MATERIAL AND METHODS: The QP/QS ratio was evaluated by pulsed and or continuous wave echo-Doppler in 50 children who were submitted within 48 hours to cardiac catheterization. All children had an intracardiac shunt (12 atrial septal defects--ASD; 26 ventricular septal defects--VSD and 12 atrio ventricular septal defects--AVDS). Identical measurements were performed in a group of 20 children without cardiac malformation--control group. To test inter-observer variability, all the measurement in 31 patients were repeated by a second observer. Pulmonary and aortic flow was calculated as: Q = A x V x ET x CF where, A is the valvular orifice area (cm2), V the mean flow velocity (cm/sec), ET the ejection time (sec) and CF the cardiac frequency (cycles/min). The Doppler beam-flow direction angle in the pulmonary (P) artery and ascending aorta (Ao) was less than 20 degrees. Results were correlated with those obtained by catheterization (oximetric method). RESULTS: We obtained a fairly good correlation with both pulsed wave Doppler (n = 43; r = 0.88; p less than 0.001; y = 0.84x + 0.40) and continuous wave Doppler (n = 50; r = 0.91; p less than 0.001; y = 0.86x + 0.35) or with pulsed wave Doppler in the P artery and continuous wave Doppler in the Ao (n = 43; r = 0.92; p less than 0.001; y = 0.86x + 0.27). In the control group, QP/QS ratio was evaluated by echo-Doppler: pulsed wave Doppler at 1.05 +/- 0.15 (mean +/- DS); continuous wave Doppler at 1.05 +/- 0.12 and, pulsed wave Doppler in the P artery and continuous wave Doppler in the Ao at 1.03 +/- 0.12. There was no significant difference in all three groups to the normal range of 1.00 (p less than 0.01). Inter-observer variability was less than 5.5% (p less than 0.001). CONCLUSION: Pulsed and/or continuous wave echo-Doppler measurements are a reliable noninvasive method in evaluating QP/QS ratio in children with isolated septal defects.     

The determinants of right ventricular function in patients with atrial septal defect

OBJECTIVE: The purpose of this study was to ascertain the determinants of right ventricular (RV) systolic and diastolic functions in patients with atrial septal defect. METHODS: Thirty-three patients with atrial septal defect having left to right shunt were enrolled in this study. RV function parameters were assessed echocardiographically. RV systolic function was assessed using tricuspid tissue Doppler S velocity (St). With regard to RV diastolic function parameters, E/A ratio, deceleration time (DT), E/Et ratio (Et = tissue Doppler E velocity), RV isovolumetric relaxation time (RVIVRT) were assessed. RV myocardial performance index (MPI) was calculated as an index of both systolic and diastolic function. Pulmonary artery stiffness (PAS) was also calculated. After echocardiography, right and left heart catheterization was performed. Mean pulmonary artery pressure (MPAP), mean right atrial pressure (MRAP), systemic flow (Qs), pulmonary flow (Qp), systemic vascular resistance (SVR), and pulmonary vascular resistance (PVR) were obtained using the data of invasive measurements. RESULTS: In multivariate analysis, MPAP was found to be the parameter closest related to RVIVRT (r = 0.73, p < 0.001) and E/Et (r = 0.66, p < 0.001), while PAS was found to be the parameter closest related to MPI (r = 0.53, p = 0.002). In addition, St velocity was found the only parameter related to PVR (r = -0.39) in univariate analysis. There was no relationship between QP/QS and any of the RV function parameters. CONCLUSION: The pulmonary vascular bed appears to be the predictor of the RV functions in patients with atrial left to right shunts, and the amount of the shunt seems to have no direct adverse influence on the RV functions.     

A new method for noninvasive estimation of ventricular septal defect shunt flow by Doppler color flow mapping: imaging of the laminar flow convergence region on the left septal surface

An accurate but simple and noninvasive method for quantifying flow across a ventricular septal defect has yet to be implemented for routine clinical use. A region of flow convergence is commonly imaged by Doppler color flow mapping on the left septal surface of the ventricular septal defect, appearing as a narrowed region of laminar flow with aliased flow velocities entering the orifice. If the first aliasing region represents a hemispheric isovelocity boundary of a surface of flow convergence and all flow at this surface crosses the ventricular septal defect, the flow through the defect can be estimated by using the radius (R), measured from the first alias to the orifice, and the Nyquist limit (NL) velocity (the flow velocity at the first alias). Doppler color flow imaging was performed in 18 children with a single membranous ventricular septal defect undergoing cardiac catheterization at a mean age of 29.8 months (Group I). Indexes of maximal flow rate across the defect were developed from either the radius or the area, obtained by planimetry, of the first alias, based on Doppler color flow images. All indexes were corrected for body surface area and compared with shunt flow (Qp-Qs) and pulmonary to systemic flow ratio (Qp/Qs) determined at cardiac catheterization. Doppler color flow indexes derived from images of flow convergence in both the long-axis (n = 15) and oblique four-chamber (n = 10) views correlated closely with Qp/Qs (r = 0.71 to 0.92) and Qp - Qs (r = 0.69 to 0.97).(ABSTRACT TRUNCATED AT 250 WORDS)     

Transatrial septal velocity measurement by Doppler echocardiography in atrial septal defect: correlation with Qp:Qs ratio

Right atrial velocities measured perpendicular to the atrial septum by Doppler echocardiography in patients with atrial septal defects (ASD) have a discernible morphology that may bear a relation to shunt magnitude. The integral of the right atrial Doppler waveform was compared with shunt magnitude measured at cardiac catheterization or nuclear shunt scan in 17 ASD patients. For control subjects, the mean right atrial velocity was 15 +/- 4 cm/s (+/- standard deviation) and that for ASD patients was 41 +/- 11 cm/s (p less than 0.001). Doppler pulmonary-to-systemic flow ratio (Qp:Qs) correlated with catheterization Qp:Qs ratio (n = 9, r = 0.85, SEE = 0.27) and with nuclear Qp:Qs ratios (n = 8, r = 0.60, SEE = 0.51). Mean transatrial septal velocity in ASD patients correlated with catheterization Qp:Qs ratio (n = 9, r = 0.8, SEE = 6.0) and with simultaneous Doppler Qp:Qs ratio (n = 16, r = 0.89, SEE = 4.9, y = 16.2 +/- 8.3). Although Qp:Qs ratio can be approximated by measuring pulmonary and systemic flow by Doppler echocardiography in many ASD patients, this newly described method allows estimation of Qp:Qs ratio. It is useful when these more conventional measurements cannot be performed because of turbulence or when inadequate imaging prevents Doppler pulmonary to systemic flow measurement.     

Noninvasive estimation of right ventricular systolic pressure in ventricular septal defect by a continuous wave Doppler technique

Noninvasive determination of right ventricular systolic pressure was attempted in 27 patients with ventricular septal defect based on the peak velocity of left-to-right shunt flow as measured in the right ventricle by a continuous wave Doppler technique. The systolic pressure gradient between the ventricles (delta p: mmHg) was calculated according to the simplified Bernoulli's formula, delta p = 4 V2, where V (m/sec) is the peak velocity of the left-to-right shunt flow. Right ventricular systolic pressure was determined by subtracting delta p from the systolic blood pressure measured in the upper arm, which was regarded as the left ventricular systolic pressure. The peak velocity of left-to-right shunt flow could be measured in all patients except one with muscular ventricular septal defect, and values ranged from 0.6 to 4.8 m/sec. The peak velocity of left-to-right shunt flow decreased inversely with the increase in right ventricular systolic pressure. The values of right ventricular systolic pressure determined by the continuous wave Doppler technique correlated highly (r = 0.820) with those determined by cardiac catheterization. The peak velocity of left-to-right shunt flow also showed high negative correlations with the pulmonary to systemic pressure ratio (r = -0.876) and pulmonary to systemic resistance ratio (r = -0.855). These results indicate that the continuous wave Doppler technique is clinically useful for determination of right ventricular systolic pressure as well as the pulmonary to systemic pressure ratio and pulmonary to systemic resistance ratio.     

Noninvasive evaluation of left-to-right shunts by pulsed Doppler echocardiography

The systemic and pulmonary blood flows and the ratio of pulmonary to systemic flow were noninvasively evaluated by pulsed Doppler echocardiography in 25 children with left-to-right shunts. Fourteen patients had atrial septal defect and 11 had ventricular septal defect. In patients with atrial septal defect, right ventricular stroke volume was obtained from the recordings of mean velocity flow and the diameter at the level of pulmonary valve in short-axis view. The left ventricular stroke volume was evaluated from the suprasternal approach by positioning the sample volume within the ascending aorta just above the valvar leaflets. In children with ventricular septal defect, the pulmonary blood flow was determined at the level of the mitral orifice, whereas the systemic blood flow was estimated from the ascending aorta. The systemic and pulmonary blood flows and their ratio determined by pulsed Doppler echocardiography in the 25 patients examined, were compared using simple linear regression analysis with the results obtained by cardiac catheterization. The ratio of pulmonary-to-systemic flow showed an excellent correlation in patients with atrial septal defect (r = 0.82) and in those with ventricular septal defect (r = 0.79). Our study validates the accuracy of cross-sectional Doppler echocardiography, especially for minimizing some possibility of errors in the presence of left-to-right shunts by employing new approaches.     

Transesophageal Doppler color flow mapping assessment of atrial septal defect

Transesophageal Doppler color flow imaging was performed in 19 adult patients (mean age 35 years) with an atrial septal defect demonstrated by cardiac catheterization or at surgery, or both. The transesophageal study correctly identified and classified 19 of 19 shunts in contrast to 16 of 18 shunts identified by the transthoracic approach. The area of the atrial septal defect was calculated by assuming it to be circular and taking the maximal Doppler color flow jet width at the defect site as its diameter. The pulsed Doppler sample volume was placed parallel to the shunt flow direction at the defect site to obtain the mean velocity and flow duration. From these values, the shunt volume was calculated as a product of the defect area, mean velocity, flow duration and heart rate. The calculated shunt flow volume obtained by transesophageal study showed a good correlation with shunt flow volume (r = 0.91, p less than 0.001) and pulmonary to systemic blood flow ratio (r = 0.84, p less than 0.001) obtained at cardiac catheterization. The size of the defect by transesophageal Doppler color flow mapping correlated fairly well with the size estimated at surgery (r = 0.73, p = 0.004). It is concluded that transesophageal Doppler color flow imaging is useful in the detection and classification of atrial septal defects and in the assessment of shunt volumes.     

Doppler assessment of interventricular pressure gradient across isolated ventricular septal defect

Continuous wave Doppler ultrasound was used to estimate the pressure gradient between the right and left ventricle for assessment of pulmonary arterial systolic pressure in 30 patients with isolated ventricular septal defect and for subsequent comparison with similar data obtained on cardiac catheterization. The age of the patients ranged from 8 months to 45 years (6.8 +/- 8.6 years). No patient had right or left ventricular outflow tract obstruction. Doppler measurements were done within 24 h of cardiac catheterization. Pressure gradient across ventricular septal defect on cardiac catheterization ranged from 7 to 95 mmHg (48 +/- 24 mmHg) and that on Doppler assessment ranged from 8 to 78 mmHg (42 +/- 20 mmHg). Doppler measurements of interventricular pressure gradient correlated well with those obtained on cardiac catheterization (r = 0.90, p less than 0.001). Correlation was better in patients with pressure gradient across ventricular septal defect less than 75 mmHg (r = 0.96). Correlation was poor in three of five patients with very small ventricular septal defects (interventricular pressure gradient greater than 75 mmHg) because the jet used was not ideal. Thus continuous wave Doppler ultrasound is an accurate noninvasive means of measuring pressure gradient across ventricular septal defect, which is a useful parameter for assessment of pulmonary artery systolic pressure in patients with isolated ventricular septal defect without right and left ventricular outflow tract obstruction.     

Uses and limitations of transthoracic echocardiography in the assessment of atrial septal defect in the adult

Two-dimensional and color Doppler echocardiography accurately detected the presence of an atrial septal defect (ASD) in 47 of 50 adults (mean age 40 years) confirmed by surgery or cardiac catheterization, or both. It correctly categorized all patients with ostium secundum and ostium primum ASD but misdiagnosed 3 of 5 patients with surgically proven sinus venosus ASD. The shunt flow volume across the ASD was calculated with the standard Doppler equation, and assuming the ASD to be circular correlated with shunt flow volume obtained by cardiac catheterization (r = 0.74). The maximum width of the color flow signals moving across the ASD was taken as its diameter. Mean flow velocity was determined either by placing a pulsed Doppler sample volume parallel to the flow across the ASD as visualized by color Doppler or by color M-mode examination, which allowed determination of flow velocities using a previously validated method that incorporates a computer analysis of pixel color intensity. The pulmonary to systemic blood flow ratio obtained by color-guided conventional Doppler interrogation of the left and right ventricular outflow tracts correlated poorly with cardiac catheterization results (r = 0.38). In patients with associated tricuspid regurgitation, the peak systolic pulmonary artery pressure obtained by color Doppler-guided continuous-wave Doppler correlated well with that obtained at cardiac catheterization (r = 0.89). The maximum color Doppler jet width of the flow across the ASD poorly correlated with ASD size estimated at surgery (r = 0.50).     

Quantification of left to right shunt in atrial septal defect using systolic time intervals derived from pulsed Doppler velocimetry

Systolic time intervals derived from Doppler velocimetry measurements were used instead of direct pulmonary to systemic flow ratio measurements in adults with atrial septal defect to quantify left to right atrial shunts. Thirteen normal subjects and 25 patients with uncomplicated atrial septal defect confirmed by cardiac catheterisation were studied. The pulmonary to systemic flow ratio (Qp:Qs) expressing the shunt size was determined by the Fick method; in normal subjects the Qp:Qs ratio was assumed to be equal to 1.0. The pulsed Doppler analogue velocity recording of flow in the pulmonary artery and the ascending aorta was taken as indicating the ejection time of each ventricle and the Q wave of the electrocardiogram as indicating the onset of systole. From these measurements the ratios of the pre-ejection periods to the ejection times (haemodynamic ratio) were calculated for each ventricle and the ratios of each variable (pre-ejection period, ejection time, and haemodynamic ratio) were calculated for both ventricles. Significant differences were found between the normal subjects and the patients with atrial septal defect for all these ratios. When the Doppler findings and the Fick measurements of Qp:Qs were compared the best linear correlation coefficient was for the left to right haemodynamic ratio. It is concluded that the use of a ratio involving several variables, such as the pre-ejection period and the ejection time for both ventricles, improves the reliability of this method, which appears to be applicable in adults.     

Bidirectional flow in congenital ventricular septal defect: a Doppler echocardiographic study

The purpose of this study was to demonstrate the value of combined two-dimensional and pulsed Doppler echocardiography (echo) in localizing and recording bidirectional flow in congenital ventricular septal defect. Eight children, aged 8 months to 16 years, with clinical signs of a ventricular septal defect, underwent two-dimensional and pulsed Doppler echo study prior to cardiac catheterization. The ventricular septal defect was documented anatomically by two-dimensional echo in all eight patients. Flow patterns in systole and diastole through the ventricular septal defect and on both sides of the defect were carefully studied. In all eight children, systolic, high velocity, pathologic, left to right flow was documented when the sampling volume was positioned on the right ventricular side of the defect. When the sampling volume was positioned inside the defect, to and fro flow, left to right in systole and right to left in diastole, was observed. In children with moderate to large defects, the diastolic flow had a peak in early diastole. Increased pressure in the right ventricle over the left ventricle during the same period was demonstrated by cardiac catheterization and coincided with the Doppler flow. The direction of flow across the defect was affected by the size of the defect and the magnitude of the net shunt. Two-dimensional and pulsed echo Doppler were shown to be useful in demonstrating the ventricular septal defect and estimating its size and hemodynamic significance noninvasively.     

Quantification of left to right shunt in atrial septal defect using systolic time intervals derived from pulsed Doppler velocimetry.

Systolic time intervals derived from Doppler velocimetry measurements were used instead of direct pulmonary to systemic flow ratio measurements in adults with atrial septal defect to quantify left to right atrial shunts. Thirteen normal subjects and 25 patients with uncomplicated atrial septal defect confirmed by cardiac catheterisation were studied. The pulmonary to systemic flow ratio (Qp:Qs) expressing the shunt size was determined by the Fick method; in normal subjects the Qp:Qs ratio was assumed to be equal to 1.0. The pulsed Doppler analogue velocity recording of flow in the pulmonary artery and the ascending aorta was taken as indicating the ejection time of each ventricle and the Q wave of the electrocardiogram as indicating the onset of systole. From these measurements the ratios of the pre-ejection periods to the ejection times (haemodynamic ratio) were calculated for each ventricle and the ratios of each variable (pre-ejection period, ejection time, and haemodynamic ratio) were calculated for both ventricles. Significant differences were found between the normal subjects and the patients with atrial septal defect for all these ratios. When the Doppler findings and the Fick measurements of Qp:Qs were compared the best linear correlation coefficient was for the left to right haemodynamic ratio. It is concluded that the use of a ratio involving several variables, such as the pre-ejection period and the ejection time for both ventricles, improves the reliability of this method, which appears to be applicable in adults.     

Evaluation of the left-to-right shunt in interatrial septal defects (ostium secundum) using Doppler echocardiography. Apropos of 12 cases

In 12 patients with inter-atrial communication (ostium secundum) (IAC-OS), and ages ranging between 8 and 63 years (mean = 21 years), the ratio between pulmonary and systemic flow (QP/QS) was evaluated with the use of Doppler ultrasonography and compared with the QP/QS obtained by oxymetric measurement during catheterization. The pulmonary or systemic flow is evaluated from the diameter of the opening (d) and the velocity curve (ITV) recorded by pulsated Doppler in the aorta and the pulmonary artery; Q = d2/4 x ITV x heart rate both examinations (sonogram and catheterization) are performed in less than 24 hours. The results show a good correlation between both methods (R = 0.948) (Y = 0.756 X + 0.692). There is no significant variation between intra- or inter-observer. The findings of this study are comparable to those already published; the main difficulty in evaluating of the QP/QS by Doppler sonography are related to the measurement of the pulmonary diameter and there recording of good velocity curves. The QP/QS evaluated by Doppler sonography from a simplified calculation method advocated by Oloez et al. (QP/QS = d2 Ap x V max Ap/d2 Ao x V max Ao were compared, in retrospect, to the data provided by catheterization. The correlation is also satisfactory (R = 0.893). The Doppler ultrasonography is therefore a reliable and reproducible method in as far as the measurement of QP/QS in young or adults subjects affected with IAC OS.     

Acute haemodynamic effects of nifedipine in patients with ventricular septal defect

The haemodynamic effects of nifedipine were studied in 14 patients (aged 8-14 years, seven male and seven female) with ventricular septal defect with and without pulmonary hypertension. All underwent left and right heart catheterisation. In each patient the pressures and heart rate were measured and blood samples were taken for oximetry before and after sublingual administration of 10 mg nifedipine. In eight patients with ventricular septal defect without pulmonary hypertension (mean pulmonary artery pressure less than 20 mm Hg) nifedipine significantly reduced the mean aortic pressure and systemic vascular resistance, and significantly increased heart rate. The other haemodynamic indices did not change significantly. In six patients with ventricular septal defect complicated by pulmonary hypertension (mean pulmonary artery pressure greater than 20 mm Hg) nifedipine significantly increased systemic output, stroke volume, and heart rate, and significantly reduced systemic vascular resistance and the pulmonary to systemic flow ratio. The other haemodynamic indices did not change significantly. Nifedipine had a beneficial effect in patients with ventricular septal defect complicated by pulmonary hypertension. It reduced the left to right shunt and increased the stroke volume. This effect was not seen in patients with ventricular septal defect uncomplicated by pulmonary hypertension.     

Acute haemodynamic effects of nifedipine in patients with ventricular septal defect.

The haemodynamic effects of nifedipine were studied in 14 patients (aged 8-14 years, seven male and seven female) with ventricular septal defect with and without pulmonary hypertension. All underwent left and right heart catheterisation. In each patient the pressures and heart rate were measured and blood samples were taken for oximetry before and after sublingual administration of 10 mg nifedipine. In eight patients with ventricular septal defect without pulmonary hypertension (mean pulmonary artery pressure less than 20 mm Hg) nifedipine significantly reduced the mean aortic pressure and systemic vascular resistance, and significantly increased heart rate. The other haemodynamic indices did not change significantly. In six patients with ventricular septal defect complicated by pulmonary hypertension (mean pulmonary artery pressure greater than 20 mm Hg) nifedipine significantly increased systemic output, stroke volume, and heart rate, and significantly reduced systemic vascular resistance and the pulmonary to systemic flow ratio. The other haemodynamic indices did not change significantly. Nifedipine had a beneficial effect in patients with ventricular septal defect complicated by pulmonary hypertension. It reduced the left to right shunt and increased the stroke volume. This effect was not seen in patients with ventricular septal defect uncomplicated by pulmonary hypertension.     

Diastolic ventricular septal motion in atrial septal defect: Analysis of M-mode echocardiograms in 31 patients

Previous echocardiographic studies suggest that diastolic motion of the ventricular septum reflects relative filling of the right and left ventricles. We studied 31 patients with atrial septal defect by M-mode echocardiography. Early diastolic posterior ventricular septal motion (DPSM) occurred in all patients. Measurement of DPSM correlated with pulmonary to systemic flow ratios (Qp:Qs) (r = 0.64, p < 0.001). All 15 patients with DPSM > 5 mm had a Qp:Qs > 2.5:1, whereas only 8 of 16 patients with DPSM < 5 mm had a shunt this large (p < 0.003). DPSM > 5 mm in patients with atrial septal defect is a specific but not sensitive echocardiographic sign of a large left-to-right shunt. Our findings substantiate the hypothesis that diastolic motion of the ventricular septum reflects relative filling of the ventricles.     

Ultrasonic enhancement of myocardial infarction with perfluorocarbon compounds in dogs

Medically pure (100%) carbon dioxide directly injected into a peripheral vein was used for 2-dimensional contrast echocardiography in 134 patients with an arteriovenous shunt demonstrated by cardiac catheterization and cineangiography, Qp/Qs ratios of 1.5 to 3.7, pulmonary-to-systemic peak systolic pressure ratios of 0.2 to 0.8 and no oximetrically demonstrable venoarterial shunt. Two patients with transposition of the great arteries, intact ventricular septum and a Senning operation as well as 30 normal subjects of comparable age also were studied. In patients with an atrial septal defect, the gas microbubbles opacified the left atrium. In patients with a ventricular septal defect, the gas microbubbles opacified the left ventricle, whereas the left atrium was free of contrast. In all patients with patent ductus arteriosus, the gas microbubbles opacified the abdominal aorta, whereas the left atrium, left ventricle, aortic root and aortic arch remained free of contrast. In 2 patients in whom an aneurysm of the sinus of Valsalva ruptured into the right ventricle, the "negative" contrast effect permitted localization of the shunt. In 2 patients with transposition of the great arteries, an intact ventricular septum and a Senning operation, the intracardiac flow pattern was clearly demonstrated. No complication was observed. We conclude that pure carbon dioxide directly injected into a peripheral vein is a safe and advantageous echocardiographic contrast material. Because of its greater diffusibility in comparison with oxygen and fluid contrast media, small venoarterial shunting can be detected in defects such as atrial septal defect, ventricular septal defect and patent ductus arteriosus, in which only an arteriovenous shunt can be demonstrated by oximetry.     

Doppler echocardiographic evaluation of left-to-right shunts in congenital heart disease

Doppler echocardiography enables the possibility of determining pulmonary to systemic flow ratios in patients with left to right shunts. Volume flow is calculated as the product of mean velocity over time, as evaluated by pulsed Doppler, and the cross-sectional area through which the flow passes. Appropriate sites for measurement of velocity and cross-sectional area of flow are the ascending aorta, right ventricular outflow tract and pulmonary artery as well as the tricuspid and mitral valve orifices. Velocity is always recorded as parallel as possible to the direction of flow. Echocardiographic measurements of the area of flow are carried out at the level of the sample volume. In the presence of an atrial or ventricular septal defect, the flow in the ascending aorta normally serves as systemic flow; alternatively, mitral or tricuspid flow may be used to cross-check these values. The latter serves for calculation of systemic flow in patent ductus arteriosus. In atrial or ventricular septal defect, the pulmonary flow is normally derived in the region of the pulmonary artery; in patent ductus arteriosus, however, in the region of the ascending aorta. As an alternative, or for confirmative use, in atrial septal defect the tricuspid flow and in ventricular septal defect and patent ductus arteriosus the mitral flow, can be taken into consideration. Studies we performed in 31 patients with atrial septal defect showed a close correlation between Doppler echocardiographic measurements and data obtained by cardiac catheterization and radionuclide studies.(ABSTRACT TRUNCATED AT 250 WORDS)     

Continuous-wave Doppler in children with ventricular septal defect: noninvasive estimation of interventricular pressure gradient

Continuous-wave Doppler was used to estimate the pressure gradient between the right and left ventricles in 28 children with ventricular septal defect (VSD). Doppler measurement of maximal velocity was performed during cardiac catheterization and the Doppler-predicted gradient was compared with the peak-to-peak gradient measured simultaneously by catheter. Doppler gradients ranged from 10 to 71 mm Hg and correlated well with measured gradient (r = 0.97, p greater than or equal to 0.001). Fourteen patients had isolated VSD, and in these patients Doppler measurements of gradient allowed accurate estimation of right ventricular pressure (r = 0.93). There was an inverse correlation between the ratio of pulmonary to systemic resistance and maximal velocity (r = -0.77). Thus, continuous-wave Doppler is an accurate means of measuring instantaneous VSD pressure gradient in children with congenital heart disease and can be used to estimate the right ventricular and pulmonary artery pressure in children with isolated VSD. This noninvasive method can be used to distinguish restrictive from nonrestrictive VSD.     

Pulmonary to systemic flow ratios in patients with ventricular septal defect: estimation by transmitral flow velocity

Using pulsed Doppler echocardiography, left ventricular inflow flow volume (LVIV) and outflow flow volume (LVOV) were noninvasively determined, and the ratio of pulmonary to systemic flow (Qp/Qs) was evaluated as the ratio of LVIV to LVOV (LVIV/LVOV). Thirty patients with ventricular septal defect (VSD) were studied, and 47 cardiac patients without aortic or mitral valve disease or intracardiac shunt served as controls. LVOV was derived from the left ventricular ejection flow velocity and the outflow tract diameter immediately proximal to the aortic valve ring. LVIV was derived from the transmitral flow velocity and the M-mode tracing of mitral valve motion. Doppler-determined cardiac outputs (COin and COout) were calculated as the products of LVIV or LVOV as and heart rates. Cardiac outputs were also determined by the dye dilution method (COdye) references for comparison with Doppler-determined cardiac outputs. There were good correlations between COdye and COin (y = 1.18x-243, r = 0.85, p less than 0.005, SEE = 1026 ml/min) and between COdye and COout (y = 1.16x-323, r = 0.90, p less than 0.005, SEE = 639 ml/min). LVIV and LVOV correlated well in the controls (y = 0.95x + 5.3, r = 0.94, p less than 0.005, SEE = 6.6 ml). LVIV/LVOV was 0.97 +/- 0.1 (mean +/- SD) in the controls; whereas LVIV/LVOV (1.86 +/- 0.90) was significantly higher in patients with VSD (p less than 0.01) and this ratio correlated well with Qp/Qs by an oximetry (r = 0.98, SEE = 0.20, n = 14), including patients associated with pulmonary regurgitation. These findings indicate that our method permits determination of LVIV with a high degree of accuracy and that the Doppler-determined LVIV/LVOV is clinically useful to evaluate accurately the magnitude of shunt flows in patients with VSD.