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Background: The hydrodynamic cause of systolic anterior motion of the mitral valve (SAM) is unresolved., Objectives: This study hypothesized that echocardiographic vector flow mapping, a new echocardiographic technique, would provide insights into the cause of early SAM in obstructive hypertrophic cardiomyopathy (HCM)., Methods: We analyzed the spatial relationship of left ventricular (LV) flow and the mitral valve leaflets (MVL) on 3-chamber vector flow mapping frames, and performed mitral valve measurements on 2-dimensional frames in patients with obstructive and nonobstructive HCM and in normal patients., Results: We compared 82 patients (22 obstructive HCM, 23 nonobstructive HCM, and 37 normal) by measuring 164 LV pre- and post-SAM velocity vector flow maps, 82 maximum isovolumic vortices, and 328 2-dimensional frames. We observed color flow and velocity vector flow posterior to the MVL impacting them in the early systolic frames of 95% of obstructive HCM, 22% of nonobstructive HCM, and 11% of normal patients (p < 0.001). In both pre- and post-SAM frames, we measured a high angle of attack >60° of local vector flow onto the posterior surface of the leaflets whether the flow was ejection (59%) or the early systolic isovolumic vortex (41%). Ricochet of vector flow, rebounding off the leaflet into the cul-de-sac, was noted in 82% of the obstructed HCM, 9% of nonobstructive HCM, and none (0%) of the control patients (p < 0.001). Flow velocities in the LV outflow tract on the pre-SAM frame 1 and 2 mm from the tip of the anterior leaflet were low: 39 and 43 cm/s, respectively., Conclusions: Early systolic flow impacts the posterior surfaces of protruding MVL initiating SAM in obstructive HCM., (Copyright © 2014 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: We tested a newly developed 4-dimensional (4D) right ventricular (RV) analysis method for computing RV volumes for both 3-dimensional (3D) ultrasound (US) and magnetic resonance (MR) images., Background: Asymmetry and the anatomical complexity of the RV make accurate determination of RV shape and volume difficult., Methods: Thirty patients, 14 with grossly normal cardiac anatomy and 16 with major congenital heart disease, were studied at the same visit with both 3D echocardiography (echo) and magnetic resonance imaging (MRI) for RV size and function. Ultrasound images were acquired on a Philips 7500 system (Philips Medical Systems, Andover, Massachusetts) with a matrix-array transducer (real-time 3D echo) with full volume sweeps from apical and subcostal views. Sagittal, 4-chamber, and coronal views were derived for contour detection (all 12 to 24 slices). The MR images were acquired with a 3-T MRI magnet with segmented cine-loop gradient echo sequences in short- and rotated long-axis views to cover the RV inflow, body, and outflow tract. The RV volumes were analyzed with the new software applicable to 3D echo MR images., Results: New software aided delineation of the RV free wall, tricuspid valve, RV outflow tract, and apex on 3D echo volumes. Although there was a slightly higher variability measuring right ventricular ejection fraction (RVEF) and volumes obtained by US compared with MRI, both imaging methods showed closely correlated results. The RVEF was measured with 4% variability for US and 5% variability for MRI with a correlation coefficient of r = 0.91. The RV end-diastolic volume was measured at 70.97 +/- 15.0 ml with 3D US and at 70.06 +/- 14.8 ml with MRI (r = 0.99), end-systolic volume measured 39.8 +/- 10.4 ml with 3D US and 39.1 +/- 10.2 ml with MRI (r = 0.98)., Conclusions: The new RV analysis software allowed validation of the accuracy of 4D echo RV volume data compared with MRI.

Over the past 3 decades, echocardiography has become a major diagnostic tool in the arsenal of clinical cardiology for real-time imaging of cardiac dynamics. More and more, cardiologists' decisions are based on images created from ultrasound wave reflections. From the time ultrasound imaging technology provided the first insight into the human heart, our diagnostic capabilities have increased exponentially as a result of our growing knowledge and developing technology. One of the most significant developments of the last decades was the introduction of 3-dimensional (3D) imaging and its evolution from slow and labor-intense off-line reconstruction to real-time volumetric imaging. While continuing its meteoric rise instigated by constant technological refinements and continuing increase in computing power, this tool is guaranteed to be integrated in routine clinical practice. The major proven advantage of this technique is the improvement in the accuracy of the echocardiographic evaluation of cardiac chamber volumes, which is achieved by eliminating the need for geometric modeling and the errors caused by foreshortened views. Another benefit of 3D imaging is the realistic and unique comprehensive views of cardiac valves and congenital abnormalities. In addition, 3D imaging is extremely useful in the intraoperative and postoperative settings because it allows immediate feedback on the effectiveness of surgical interventions. In this article, we review the published reports that have provided the scientific basis for the clinical use of 3D ultrasound imaging of the heart and discuss its potential future applications.

The Working Group on research in adult congenital heart disease (ACHD) was convened in September 2004 under the sponsorship of National Heart, Lung, and Blood Institute (NHLBI) and the Office of Rare Diseases, National Institutes of Health, Department of Health and Human Services, to make recommendations on research needs. The purpose of the Working Group was to advise the NHLBI on the current state of the science in ACHD and barriers to optimal clinical care, and to make specific recommendations for overcoming those barriers. The members of the Working Group were chosen to provide expert input on a broad range of research issues from both scientific and lay perspectives. The Working Group reviewed data on the epidemiology of ACHD, long-term outcomes of complex cardiovascular malformations, issues in assessing morphology and function with current imaging techniques, surgical and catheter-based interventions, management of related conditions including pregnancy and arrhythmias, quality of life, and informatics. After research and training barriers were discussed, the Working Group recommended outreach and educational programs for adults with congenital heart disease, a network of specialized adult congenital heart disease regional centers, technology development to support advances in imaging and modeling of abnormal structure and function, and a consensus on appropriate training for physicians to provide care for adults with congenital heart disease.

Objectives: We sought to evaluate the effects of biventricular (BDOO) pacing compared with conventional (CDOO) atrioventricular (AV) sequential and atrial (AOO) pacing in children and infants in the early postoperative period after open heart surgery for congenital heart disease (CHD)., Background: Biventricular pacing using right ventricular (RV) and left ventricular (LV) leads can improve hemodynamics in patients with CHD, but it is unclear whether this occurs in early postoperative children with CHD., Methods: Nineteen children (age, 5 days to 5.4 years; median, 5.5 months) with a definitive biventricular repair for CHD underwent AOO, CDOO, and BDOO pacing with temporary epicardial leads for 10 min each. The AV delay was 80% of the PR interval for the CDOO and BDOO modes. Lead placement was two right atrial, two RV, and one LV. Blood samples for cardiac index (arterial and venous) and tissue Doppler (TDI) traces were obtained in each pacing mode with a Vivid 7 BT04 digital ultrasound system (GE/VingMed, Horten, Norway) from an apical four-chamber view and analyzed with EchoPac software., Results: The QRS duration was significantly shorter for BDOO compared with CDOO, and the cardiac index was higher with BDOO compared with CDOO. Systemic blood pressure was not different between the three modes of pacing (AOO, CDOO, BDOO). The TDI-derived strain rate showed minimal dyssynchrony in AOO as seen by isovolumic tensing (IVT) and peak systolic contraction (PSC) timing differences between RV and LV. The CDOO worsened dyssynchrony with prolonged DeltaIVT and PSC. The BDOO showed improved synchrony as seen by DeltaIVT and PSC., Conclusions: The TDI-derived strain rate showed worsened ventricular dyssynchrony with CDOO and improvement with BDOO. Cardiac index and QRS duration were improved by BDOO compared with CDOO. This suggests that short-term pacing with BDOO may benefit children with CHD needing pacing in the postoperative period.

Objectives: The purpose of this study was to investigate whether cardiac output (CO) could be accurately computed from live three-dimensional (3-D) Doppler echocardiographic data in an acute open-chested animal preparation., Background: The accurate measurement of CO is important in both patient management and research. Current methods use invasive pulmonary artery catheters or two-dimensional (2-D) echocardiography or esophageal aortic Doppler measures, with the inherent risks and inaccuracies of these techniques., Methods: Seventeen juvenile, open-chested pigs were studied before undergoing a separate cardiopulmonary bypass procedure. Live 3-D Doppler echocardiography images of the left ventricular outflow tract and aortic valve were obtained by epicardial scanning, using a Philips Medical Systems (Andover, Massachusetts) Sonos 7500 Live 3-D Echo system with a 2.5-MHz probe. Simultaneous CO measurements were obtained from an ultrasonic flow probe placed around the aortic root. Subsequent offline processing using custom software computed the CO from the digital 3-D Doppler DICOM data, and this was compared to the gold standard of the aortic flow probe measurements., Results: One hundred forty-three individual CO measurements were taken from 16 pigs, one being excluded because of severe aortic regurgitation. There was good correlation between the 3-D Doppler and flow probe methods of CO measurement (y = 1.1x - 9.82, R(2) = 0.93)., Conclusions: In this acute animal preparation, live 3-D Doppler echocardiographic data allowed for accurate assessment of CO as compared to the ultrasonic flow probe measurement.

Objectives: Our purpose was to evaluate a tissue Doppler-based index-peak myocardial acceleration (pACC)-during isovolumic relaxation and in evaluating left ventricular (LV) diastolic function., Background: Simple, practical indexes for diastolic function evaluation are lacking, but are much desired for clinical evaluation., Methods: We examined eight sheep by using tissue Doppler ultrasound images obtained in the apical four-chamber views to evaluate mitral valve annular velocity at the septum and LV wall. The pACC thus derived was analyzed during isovolumic relaxation (IVRT) and during the LV filling period (LVFP). We then changed the hemodynamic status of each animal by blood administration, dobutamine, and metoprolol infusion. We compared the pACC values during IVRT and LVFP over the four different hemodynamic conditions with a peak rate of drop in LV pressure (-dP/dt(min)) and the time constant of LV isovolumic pressure decay (tau), as measured with a high-frequency manometer-tipped catheter., Results: The pACC of the septal side of the mitral valve annulus during IVRT showed a good correlation with -dP/dt(min) (r = -0.80, p < 0.0001) and tau (r = -0.87, p < 0.0001). The mean left atrial pressure (LAP) correlated well with the septal side pACC during LVFP (r = 0.81, p < 0.0001). There was a weak correlation between the mitral valve annulus pACC at the LV lateral wall and mean LAP., Conclusions: The pACC during IVRT is a sensitive, preload-independent marker for evaluation of LV diastolic function. In addition, pACC during LVFP correlated well with mean LAP.

Objectives: This study was performed to evaluate subendocardial function using strain rate imaging (SRI)., Background: The subendocardium and mid-wall of the left ventricle (LV) play important roles in ventricular function. Previous methods used for evaluating this function are either invasive or cumbersome. Strain rate imaging by ultrasound is a newly developed echocardiographic modality based on tissue Doppler imaging (TDI) that allows quantitative assessment of regional myocardial wall motion., Methods: We examined eight sheep using TDI in apical four-chamber views to evaluate the LV free wall. Peak strain rates (SRs) during isovolumic relaxation (IR), isovolumic contraction (IC), and myocardial strain were measured in the endocardial (End), mid-myocardial (Mid), and epicardial (Epi) layers. For four hemodynamic conditions (created after baseline by blood, dobutamine, and metoprolol infusion), we compared differences in SR of End, Mid, and Epi layers to peak positive and negative first derivative of LV pressure (dP/dt)., Results: Strain rate during IC showed a good correlation with +dP/dt (r = 0.74, p < 0.001) and during IR with -dP/dt (r = 0.67, p = 0.0003). There was a significant difference in SR between the myocardial layers during both IC and IR (End: -3.4 +/- 2.2 s(-1), Mid: -1.8 +/- 1.5 s(-1), Epi: -0.63 +/- 1.0 s(-1), p < 0.0001 during IC; End: 2.2 +/- 1.5 s(-1), Mid: 1.0 +/- 0.8 s(-1), Epi: 0.47 +/- 0.64 s(-1), p < 0.0001 during IR). Also, SRs of the End and Mid layers during IC were significantly altered by different hemodynamic conditions (End at baseline: 1.7 +/- 0.7 s(-1); blood: 2.0 +/- 1.1 s(-1); dobutamine: 3.4 +/- 2.3 s(-1); metoprolol: 1.0 +/- 0.4 s(-1); p < 0.05). Myocardial strain showed differences in each layer (End: -34.3 +/- 12.6%; Mid: -22.6 +/- 12.1%; Epi: -11.4 +/- 7.9%; p < 0.0001) and changed significantly in different hemodynamic conditions (p < 0.0001)., Conclusions: Strain and SR appear useful and sensitive for evaluating myocardial function, especially for the subendocardial region.

Objectives: The purpose of the present study was to validate a newly developed three-dimensional (3D) digital color Doppler method for quantifying pulmonary regurgitation (PR), using an animal model of chronic PR., Background: Spectral Doppler methods cannot reliably be used to assess pulmonary regurgitation., Methods: In eight sheep with surgically created PR, 27 different hemodynamic states were studied. Pulmonary and aortic electromagnetic (EM) probes and meters were used to provide reference right ventricular (RV) forward and pulmonary regurgitant stroke volumes. A multiplane transesophageal probe was placed directly on the RV and aimed at the RV outflow tract. Electrocardiogram-gated and rotational 3D scans were performed for acquiring dynamic 3D digital velocity data. After 3D digital Doppler data were transferred to a computer workstation, the RV forward and pulmonary regurgitant flow volumes were obtained by a program that computes the velocity vectors over a spherical surface perpendicular to the direction of scanning., Results: Pulmonary regurgitant volumes and RV forward stroke volumes computed by the 3D method correlated well with those by the EM method (r = 0.95, mean difference = 0.51 +/- 1.89 ml/beat for the pulmonary regurgitant volume; and r = 0.91, mean difference = -0.22 +/- 3.44 ml/beat for the RV stroke volume). As a result of these measurements, the regurgitant fractions derived by the 3D method agreed well with the reference data (r = 0.94, mean difference = 2.06 +/- 6.11%)., Conclusions: The 3D digital color Doppler technique is a promising method for determining pulmonary regurgitant volumes and regurgitant fractions. It should have an important application in clinical settings.

Objectives: The purpose of this study was to validate a digital color Doppler (DCD) automated cardiac flow measurement method for quantifying pulmonary regurgitation (PR) in an in vitro and a chronic animal model of the right ventricular outflow tract of postoperative tetralogy of Fallot (TOF)., Background: There has been no reliable ultrasound method that can accurately quantitate PR., Methods: We developed an in vitro model of mild pulmonary stenosis and wide-open PR that mimics the patterns of flow seen in patients with postoperative TOF. Thirteen different forward and regurgitant stroke volumes (RSVs) across the noncircular shaped cross-sectional outflow tract flow area were estimated using the DCD method in two orthogonal planes. In six sheep with surgically created PR, 24 different hemodynamic states with PR strictly quantified by electromagnetic probes were also studied., Results: The RSVs and regurgitant fractions (RFs) obtained by the DCD method using average values from two orthogonal planes correlated well with reference values (RSV: r = 0.99, mean difference = 0.02 +/- 0.39 ml/beat for in vitro model; r = 0.97, mean differences = 1.79 +/- 1.84 ml/beat for animal model, RF: r = 0.98, mean difference = -1.10 +/- 4.34% for in vitro model; r = 0.94, mean difference = 2.73 +/- 6.75% for animal model). However, the DCD method using a single plane had limited accuracy for estimating pulmonary RFs and RSVs., Conclusions: The DCD method using average values from two orthogonal planes provides accurate estimation of RSVs and RFs and should have clinical importance for serially quantifying PR in patients with postoperative TOF.

Objectives: The aim of the present study was to quantitate shunt flow volumes through atrial septal defects (ASDs) in a chronic animal model with surgically created ASDs using a new semiautomated color Doppler flow calculation method (ACM)., Background: Because pulsed Doppler is cumbersome and often inappropriate for color flow computation, new methods such as ACM are of interest., Methods: In this study, 13 to 25 weeks after ASDs were surgically created in eight sheep, a total of 24 hemodynamic states were studied at a separate open chest experimental session. Electromagnetic (EM) flow probes and meters were used to provide reference flow volumes as the pulmonary and aortic flow volumes (Qp and Qs) and shunt flow volumes (Qp minus Qs). Epicardial echocardiographic studies were performed to image the left and right ventricular outflow tract (LVOT and RVOT) forward flow signals. The ACM method digitally integrated spatial and temporal color flow velocity data to provide stroke volumes. RESULTS Left ventricular outflow tract and RVOT flow volumes obtained by the ACM method agreed well with those obtained by the EM method (r = 0.96, mean difference = 0.78 +/- 1.7 ml for LVOT and r = 0.97, mean difference = -0.35 +/- 3.6 ml for RVOT). As a result, shunt flow volumes and Qp/Qs by the ACM method agreed well with those obtained by the EM method (r = 0.96, mean difference = -1.1 +/- 3.6 ml/beat for shunt volumes and r = 0.95, mean difference = -0.11 +/- 0.22 for Qp/Qs)., Conclusions: This animal study, using strictly quantified shunt flow volumes, demonstrated that the ACM method can provide Qp/Qs and shunt measurements semiautomatically and noninvasively.

Objectives: This study was performed to compare the safety and efficacy of intravenous 2% dodecafluoropentane (DDFP) emulsion (EchoGen) with that of active control (sonicated human albumin [Albunex]) for left ventricular (LV) cavity opacification in adult patients with a suboptimal echocardiogram., Background: The development of new fluorocarbon-based echocardiographic contrast agents such as DDFP has allowed opacification of the left ventricle after peripheral venous injection. We hypothesized that DDFP was clinically superior to the Food and Drug Administration-approved active control., Methods: This was a Phase III, multicenter, single-blind, active controlled trial. Sequential intravenous injections of active control and DDFP were given 30 min apart to 254 patients with a suboptimal echocardiogram, defined as one in which the endocardial borders were not visible in at least two segments in either the apical two- or four-chamber views. Studies were interpreted in blinded manner by two readers and the investigators., Results: Full or intermediate LV cavity opacification was more frequently observed after DDFP than after active control (78% vs. 31% for reader A; 69% vs. 34% for reader B; 83% vs. 55% for the investigators, p < 0.0001). LV cavity opacification scores were higher with DDFP (2.0 to 2.5 vs. 1.1 to 1.5, p < 0.0001). Endocardial border delineation was improved by DDFP in 88% of patients versus 45% with active control (p < 0.001). Similar improvement was seen for duration of contrast effect, salvage of suboptimal echocardiograms, diagnostic confidence and potential to affect patient management. There was no difference between agents in the number of patients with adverse events attributed to the test agent (9% for DDFP vs. 6% for active control, p = 0.92)., Conclusions: This Phase III multicenter trial demonstrates that DDFP is superior to sonicated human albumin for LV cavity opacification, endocardial border definition, duration of effect, salvage of suboptimal echocardiograms, diagnostic confidence and potential to influence patient management. The two agents had similar safety profiles.

Objectives: This study sought to evaluate the relation between the color Doppler-imaged vena contracta and the severity of mitral regurgitation (MR) in a chronic animal model of MR., Background: The vena contracta, which is defined as the smallest connection between the laminar flow acceleration zone and the turbulent regurgitant jet, has been reported to be a clinically useful marker for evaluating the severity of valvular regurgitation., Methods: Six sheep with chronic MR produced by previous operation severing the chordae tendineae were examined. MR jet flows and vena contracta widths were imaged using a Vingmed 775 scanner with a 5-MHz transducer. Image data were directly transferred in digital format to a microcomputer for off-line measurement. MR was quantified as peak and mean regurgitant flow rates, regurgitant stroke volumes and regurgitant fractions determined using mitral and aortic electromagnetic flow probes and flowmeters balanced against each other., Results: Vena contracta width correlated well with regurgitant severity determined by electromagnetic flowmeters (r = 0.95, SEE = 0.05 cm, p < 0.0001 for peak regurgitant flow rate; r = 0.85, SEE = 0.08 cm, p < 0.0001 for regurgitant stroke volume; r = 0.90, SEE = 0.07 cm, p < 0.0001 for regurgitant fraction)., Conclusions: This study shows that the vena contracta width method is useful for predicting the severity of MR. It is simple and conveniently available with high resolution equipment. The quantitative comparisons in the present study lay the foundation for future clinical and research studies using this vena contracta technique.

Objectives: The aim of the present study was to quantitate aortic regurgitant volume and regurgitant fraction in a chronic animal model with surgically created aortic regurgitation using a new semiautomated color Doppler flow calculation method., Background: The conventional noninvasive methods for evaluating the severity of aortic regurgitation have not been accepted widely nor compared with truly quantitative reference standards., Methods: Eight to 20 weeks after aortic regurgitation was surgically induced in six sheep, a total of 22 hemodynamic states were studied. Electromagnetic flow probes and meters provided reference flow data. Epicardial color Doppler echocardiographic studies were performed to image left ventricular outflow tract forward and aortic regurgitant blood flows. The new method digitally integrated spatial and temporal color flow velocity data for left ventricular outflow tract forward flow and ascending aortic regurgitant flow. The pulsed Doppler method using the velocity-time integral was also used to obtain regurgitant volumes and regurgitant fractions., Results: Regurgitant volumes and regurgitant fractions by the new method agreed well with those obtained electromagnetically, whereas the pulsed Doppler method overestimated these reference data (mean [+/-SD] difference 0.23 +/- 2.9 ml vs. 11 +/- 5.8 ml, p < 0.0001 for regurgitant volume; mean difference 1.2 +/- 7.6% vs. 19 +/- 13%, p < 0.0001 for regurgitant fraction)., Conclusions: This animal study, using strictly quantified aortic regurgitant volumes, demonstrated that the digital color Doppler method provides accurate aortic regurgitant volumes and regurgitant fractions without cumbersome measurements.

Objectives: This study sought to investigate the applicability of a current implementation of a three-dimensional echocardiographic reconstruction method for color Doppler flow convergence and regurgitant jet imaging., Background: Evaluation of regurgitant flow events, such as flow convergences or regurgitant jets, using two-dimensional imaging ultrasound color flow Doppler systems may not be robust enough to characterize these spatially complex events., Methods: We studied two in vitro models using steady flow to optimize results. In the first constant-flow model, two different orifices were each mounted to produce flow convergences and free jets--a circular orifice and a rectangular orifice with orifice area of 0.24 cm(2). In another flow model, steady flows through a circular orifice were directed toward a curved surrounding wall to produce wall adherent jets. Video composite data of color Doppler flow images from both free jet and wall jet models were reconstructed and analyzed after computer-controlled 180 degrees rotational acquisition using a TomTec computer., Results: For the free jet model there was an excellent relation between actual flow rates and three-dimensional regurgitant jet volumes for both circular and rectangular orifices (r = 0.99 and r = 0.98, respectively). However, the rectangular orifice produced larger jet volumes than the circular orifice, even at the same flow rates (p < 0.0001). Calculated flow rates by the hemispheric model using one axial measurement of the flow convergence isovelocity surface from two-dimensional color flow images underestimated actual flow rate by 35% for the circular orifice and by 44% for the rectangular orifice, whereas a hemielliptic method implemented using three axial measurements of the flow convergence zone derived using three-dimensional reconstruction correlated well with and underestimated actual flow rate to a lesser degree (22% for the circular orifice, 32% for the rectangular orifice). In the wall jet model, the jets were flattened against and spread along the wall and had reduced regurgitant jet volumes compared with free jets (p < 0.01)., Conclusions: Three-dimensional reconstruction of flow imaged by color Doppler may add quantitative spatial information to aid computation methods that have been used for evaluating valvular regurgitation, especially where they related to complex geometric flow events.

Objectives: This study was performed to define the significance of Doppler color flow mapping in demonstrating reversal of the direction of the normal physiologic flow across the atrial septum and ductus arteriosus in the human fetus., Background: Reversal of the physiologic shunting across the ductus arteriosus or atrial septum in utero (i.e., left to right) can be readily identified by Doppler color flow mapping, complemented by pulsed and continuous wave Doppler information., Methods: We reviewed echocardiograms recorded at our three institutions from 1988 to 1993, which displayed reversal of flow by Doppler color flow in 53 fetuses of gestational age 18 weeks to term. The diagnoses were confirmed by postnatal echocardiography, operation or autopsy. Reversal of shunting was consistently associated with severe heart disease., Results: Reversed atrial shunting was found with severe left heart obstructive lesions, including 19 with hypoplastic left heart syndrome, 3 with critical aortic stenosis, 2 with double-outlet right ventricle and 1 each with an interrupted aortic arch, atrioventricular septal defect and severe left ventricular dysfunction due to dilated cardiomyopathy. Reversed ductus arteriosus shunting was found with severe right heart obstructive lesions, including nine fetuses with pulmonary atresia, six with severe obstructive tricuspid valve abnormalities, five with severe tetralogy of Fallot, four with Ebstein's anomaly and two with single ventricle and pulmonary stenosis. Associated cardiac lesions were common in both groups. Only 3 of the 15 infants who were delivered alive from the reverse ductus arteriosus shunt group and 4 of 12 from the reverse atrial shunt group still survive., Conclusions: The finding of reversed flow by Doppler color flow mapping during fetal life provides a key to subsequent accurate diagnosis and denotes a spectrum of diseases with a very poor prognosis.

Spatial appreciation of flow velocities using Doppler color flow mapping has led to quantitative evaluation of the zone of flow convergence proximal to a regurgitant orifice. Based on the theory of conservation of mass, geometric analysis, assuming a series of hemispheric shells of increasing velocity as flow converges on the orifice--the so-called proximal isovelocity surface area (PISA) effect--has yielded methods promising noninvasive measurement of regurgitant flow rate. When combined with conventional Doppler ultrasound to measure orifice velocity, regurgitant orifice area, the major predictor of regurgitation severity, can also be estimated. The high temporal resolution of color M-mode can be used to evaluate dynamic changes in orifice area, as seen in many pathologic conditions, which enhances our appreciation of the pathophysiology of regurgitation. The PISA methodology is potentially applicable to any restrictive orifice and has gained some credibility in the quantitative evaluation of other valve pathology, particularly mitral and tricuspid regurgitation, and in congenital heart disease. Although the current limitations of PISA estimates of regurgitation have tempered its introduction as a valuable clinical tool, considerable efforts in in vitro and clinical research have improved our understanding of the problems and limitations of the PISA methodology and provided a firm platform for continuing research into the accurate quantitative assessment of valve regurgitation and the expanding clinical role of quantitative Doppler color flow mapping.

Objectives: The aim of the present study was to validate a digital color Doppler-based centerline velocity/distance acceleration profile method for evaluating the severity of aortic regurgitation., Background: Clinical and in vivo experimental applications of the flow convergence axial centerline velocity/distance profile method have recently been used to estimate regurgitant flow rates and regurgitant volumes in the presence of mitral regurgitation., Methods: In six sheep, a total of 19 hemodynamic states were obtained pharmacologically 14 weeks after the original operation in which a portion of the aortic noncoronary (n = 3) or right coronary (n = 3) leaflet was excised to produce aortic regurgitation. Echocardiographic studies were performed to obtain complete proximal axial flow acceleration velocity/distance profiles during the time of peak regurgitant flow (usually early in diastole) for each hemodynamic state. For each steady state, the severity of aortic regurgitation was assessed by measurement of the magnitude of the regurgitant flow volume/beat, regurgitant fraction and instantaneous regurgitant flow rates determined by using both aortic and pulmonary artery electromagnetic flow probes., Results: Grade I regurgitation (regurgitant volume/beat < 15 ml, six conditions), grade II regurgitation (regurgitant volume/beat between 16 ml and 30 ml, five conditions) and grade III-IV regurgitation (regurgitant volume/beat > 30 ml, eight conditions) were clearly separated by using the color Doppler centerline velocity/distance profile domain technique. Additionally, an equation for correlating "a" (the coefficient from the multiplicative curve fit for the velocity/distance relation) with the peak regurgitant flow rates (Q [liters/min]) was derived showing a high correlation between calculated peak flow rates by the color Doppler method and the actual peak flow rates (Q = 13a + 1.0, r = 0.95, p < 0.0001, SEE = 0.76 liters/min)., Conclusions: This study, using quantified aortic regurgitation, demonstrates that the flow convergence axial centerline velocity/distance acceleration profile method can be used to evaluate the severity of aortic regurgitation.

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.

Objectives: The aim of the present study was to investigate dynamic changes in the mitral regurgitant orifice using electromagnetic flow probes and flowmeters and the color Doppler flow convergence method., Background: Methods for determining mitral regurgitant orifice areas have been described using flow convergence imaging with a hemispheric isovelocity surface assumption. However, the shape of flow convergence isovelocity surfaces depends on many factors that change during regurgitation., Methods: In seven sheep with surgically created mitral regurgitation, 18 hemodynamic states were studied. The aliasing distances of flow convergence were measured at 10 sequential points using two ranges of aliasing velocities (0.20 to 0.32 and 0.56 to 0.72 m/s), and instantaneous flow rates were calculated using the hemispheric assumption. Instantaneous regurgitant areas were determined from the regurgitant flow rates obtained from both electromagnetic flowmeters and flow convergence divided by the corresponding continuous wave velocities., Results: The regurgitant orifice sizes obtained using the electromagnetic flow method usually increased to maximal size in early to midsystole and then decreased in late systole. Patterns of dynamic changes in orifice area obtained by flow convergence were not the same as those delineated by the electromagnetic flow method. Time-averaged regurgitant orifice areas obtained by flow convergence using lower aliasing velocities overestimated the areas obtained by the electromagnetic flow method ([mean +/- SD] 0.27 +/- 0.14 vs. 0.12 +/- 0.06 cm2, p < 0.001), whereas flow convergence, using higher aliasing velocities, estimated the reference areas more reliably (0.15 +/- 0.06 cm2)., Conclusions: The electromagnetic flow method studies uniformly demonstrated dynamic change in mitral regurgitant orifice area and suggested limitations of the flow convergence method.

Objectives: This study investigated the proximal centerline flow convergence region simultaneously by both color Doppler and laser Doppler velocimetry., Background: Although numerous investigations have been performed to test the flow convergence method, to our knowledge there has yet been no experimental study using reference standard velocimetric techniques to define precisely the hydrodynamic factors involved in the accelerating flow region during steady and pulsatile flow., Methods: Using an in vitro model that allows velocity measurements by laser Doppler velocimetry with simultaneous comparison with color Doppler results, we studied the centerline flow acceleration region proximal to orifices of various sizes (0.08 to 2.0 cm2)., Results: Agreement between theory and experimental velocities was good for large flow rates through small orifices only, and only at distances > 1.2 cm from the orifice. Changing the orifice shape from circular to slitlike produced no significant changes in velocity profiles. Constraining the proximal side walls caused a significant increase in proximal velocities at distances > 0.7 cm for the largest orifice only (2.0 cm2). Calculated flow rates agreed well with actual flow rates, with functional dependence on proximal distance and orifice size. Velocity profiles for pulsatile flow were similar to steady state flow profiles and could be integrated to calculate stroke volumes, which followed actual flow volumes well, although with general overestimation (y = 1.22x + 0.164, r = 0.92), most likely due to the use of all available proximal velocities., Conclusions: The accelerating proximal flow region responds to several hydrodynamic factors that can affect flow quantitation using the flow convergence method in the clinical situation.

Objectives: This study was designed to define patterns of pulmonary artery and aortic growth in fetuses with tetralogy of Fallot and to determine the potential for in utero progression of right ventricular outflow tract obstruction., Background: Despite an abundance of reports documenting the prenatal diagnosis of tetralogy of Fallot, there is little information about its course in utero., Methods: Pulmonary artery and ascending aortic diameters were measured from prenatal and postnatal echocardiograms of 16 fetuses with tetralogy of Fallot, initially studied at 23.6 +/- 6.0 (mean +/- SD) weeks of gestation. Fetuses were classified retrospectively as having mild and severe tetralogy of Fallot according to whether the pulmonary artery circulation was (severe, n = 5) or was not (mild, n = 11) ductus arteriosus dependent at birth., Results: Initial main pulmonary artery diameter was small for gestational age in 9 fetuses, large in 2 and normal in 5 compared with data from 57 gestational age-adjusted normal fetal studies; it was significantly smaller in the group with severe tetralogy of Fallot (p = 0.05). The initial main pulmonary artery/aortic diameter ratio was also smaller for the group with severe tetralogy of Fallot (0.50 +/- 0.15 vs. 0.73 +/- 0.14 in the group with mild tetralogy of Fallot, p = 0.01). Initial aortic and branch pulmonary artery diameters tended to be normal or near normal for age. In eight fetuses serially studied, main and branch pulmonary artery growth was normal or reduced during prenatal follow-up. Pulmonary artery growth was most reduced in two fetuses in the group with severe tetralogy of Fallot, resulting in pulmonary artery hypoplasia at birth. Two fetuses with valvular pulmonary atresia at birth had previously shown anterograde pulmonary outflow in midgestation, suggesting progression of pulmonary outflow obstruction., Conclusions: The postnatal spectrum of pulmonary artery size in tetralogy of Fallot can be attributed to variable patterns of growth in utero. Main pulmonary artery size, main pulmonary artery/aortic diameter ratio and pattern of pulmonary artery growth may be predictive of the severity of postnatal pulmonary outflow obstruction. Pulmonary atresia can develop in utero in some fetuses with tetralogy of Fallot.

Objectives: This study examined the influence of regurgitant volume on pulmonary venous blood flow patterns in an animal model with quantifiable mitral regurgitation., Background: Systolic pulmonary venous blood flow is influenced by atrial filling and compliance and ventricular output and by the presence of mitral regurgitation. The quantitative severity of the regurgitant volume itself is difficult to judge in clinical examinations., Methods: Six sheep with chronic mitral regurgitation produced by previous operation to create chordal damage were examined. At reoperation the heart was exposed and epicardial echocardiography performed. Pulmonary venous blood flow waveforms were recorded by pulsed Doppler under color flow Doppler guidance using a Vingmed 750 scanner. The pulmonary venous systolic inflow to the left atrium was expressed as a fraction of the total inflow velocity time integral. Flows across the aortic and mitral valves were recorded by electromagnetic flowmeters balanced against each other. Pressures in the left ventricle and left atrium were measured directly with high fidelity manometer-tipped catheters. Preload and afterload were systematically manipulated, resulting in 24 stable hemodynamic states., Results: Simple logarithmic correlation between the regurgitant volume and size of a positive or negative pulmonary venous inflow velocity time integral during systole was good (r = -0.841). By stepwise linear regression analysis with pulmonary venous negative systolic velocity time integral as a dependent variable compared with the regurgitant volume, fractional shortening, left atrial v wave size, systemic vascular resistance and left ventricular systolic pressure, only contributions from v wave size and regurgitant volume (r = 0.80) reached statistical significance in determining pulmonary venous negative systolic flow., Conclusions: Evaluation of systolic pulmonary venous blood flow velocity time integral can give valuable information helpful for estimating the regurgitant volume secondary to 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.

Objectives: In this study we investigated the centerline velocity profile method for flow computation as applied to noncircular, as well as circular, orifices using digital color flow data., Background: Recently it has been suggested that flow volume through an orifice can be estimated more accurately by computing the axial "centerline" flow velocity/distance profile proximal to the orifice., Methods: A total of seven different orifices were mounted in a constant-flow model: four circular orifices, two rectangular orifices with a major/minor axis ratio of 4:1 and 8:1 and an ovoid orifice having a major/minor axis ratio of 2:1. Three different flow rates were examined (1.68, 3.48 and 6.48 liters/min). Digital measurements of flow velocity at discrete positions along the centerline progressing toward the orifice were analyzed to yield complete flow velocity profiles for each orifice at each flow rate., Results: A clear separation of the flow profiles for the three different flow rates was observed independent of orifice size for all of the circular orifices. The velocity/distance acceleration curves showed highly significant correlations using multiplicative regression fits (y = ax-b, r = 0.94 to 0.99, all p < 0.0001). An equation for quantitatively correlating the a and b coefficients from the multiplicative regression fits with flow rates was derived from stepwise regression analysis: Flow rate = 23a + 3.3b - 1.5 (r = 0.97, p < 0.0001, SEE 0.46 liter/min)., Conclusions: In view of the various sizes and shapes encountered clinically for regurgitant orifices, the simplicity of this method for the estimation of the severity of regurgitant lesions might be of importance for clinical applications of this method.

Objectives: The purpose of this study was to test observations that might aid prenatal prediction of the presence of coarctation of the aorta in newborn infants with and without other forms of heart disease., Background: Previous reports have suggested that abnormal growth of the aortic arch in utero may be identifiable as a marker for the diagnosis of coarctation., Methods: We reviewed the prenatal echocardiograms and postnatal outcome of 20 infants (gestational age at initial study 18 to 36 weeks) with coarctation of the aorta established postnatally, to identify echocardiographic findings that would most facilitate the prenatal diagnosis of coarctation. Associated cardiac lesions included double-inlet left ventricle anatomy (n = 5), double-outlet right ventricle (n = 4), abnormal aortic valve (n = 5), unbalanced atrioventricular canal (n = 3), and membranous ventricular septal defect (n = 1). Chromosomal abnormalities included XO karyotype (n = 1), trisomy 18 (n = 1), and trisomy 21 (n = 1)., Results: Hypoplasia determined by measurement of the distal aortic arch was the most frequently observed finding among the fetuses with coarctation. In 12 of 15 fetuses with a well visualized transverse arch at initial prenatal study, the diameter of the transverse arch was < or = 3rd percentile for gestational age as compared with that in a normal group of fetuses. Ten of 10 fetuses with adequate images of the isthmus had isthmus hypoplasia at prenatal study with a diameter < or = 3rd percentile for gestational age. On serial study in six of seven, including three fetuses with normal distal arch measurements at initial study, the distal arch became progressively more hypoplastic for gestational age. In three there was no growth of the transverse arch or isthmus on serial study, and in three there was reversal of flow from antegrade to retrograde through the distal arch., Conclusions: In our study, quantitative hypoplasia of the isthmus and transverse arch was the most consistent observation and therefore the most definitive antenatal sign of postnatal coarctation. The potential for progression of distal arch hypoplasia necessitates serial study in fetuses with associated cardiac and noncardiac lesions.

Objectives: The present study was designed to estimate the influence of different-shaped adjacent surfaces on regurgitant jets as assessed by color Doppler imaging and laser-illuminated dye optical visualization., Background: Because color Doppler techniques provide real-time two-dimensional imaging of flow, the evaluation of valvular regurgitation by analysis of variance-encoded regurgitant jets by this method has been widely used in clinical studies. However, recent studies have demonstrated that color Doppler jet sizes are affected not only by several hemodynamic factors and instrument settings but also by the interaction between jets and adjacent wall surfaces. In clinical conditions, jets may interact with adjacent walls of variable shapes that might have different effects on the jet size., Methods: An in vitro model was constructed consisting of a rigid, optically clear receiving chamber that had no outlet resistance and had a pulsatile pump ejecting through 1.5, 2.3 and 3.1 mm2 inflow orifices into the chamber. The surfaces were flat or smoothly and equally curved, convex and concave aluminum positioned at 0, 2 and 4 mm from and to the side of the inflow orifices. The pump was run with stroke volumes from 0.5 to 3.0 ml and with a pulse frequency of 70 beats/min. The echocardiographic and laser beams were aimed at the inflow orifice imaging jets perpendicular to the surfaces (vertical view) through the central plane of the jet flows. Maximal jet areas were measured by both color Doppler techniques and laser-illuminated dye visualization., Results: Color Doppler study showed fair correlation between the jet areas and the stroke volumes (r = 0.83 to 0.99), but the jet sizes under different surface conditions were variable. All the surface jet areas at a jet-surface distance of 0 and 2 mm were smaller than free jet areas at the same stroke volume for both flat and convex surfaces (p < 0.001). Flow constraint by the concave surface resulted in the smallest jet areas (p < 0.001). The color Doppler jet areas on the curved surfaces were significantly smaller than the laser-illuminated dye visualization jet areas (p < 0.01 to 0.0001). However, at intermediate jet-surface distances (4 mm and sometimes 2 mm with higher velocity flows), jet interaction with the flat and especially with the convex surface resulted in larger jets. This effect was most pronounced on dye fluorescence studies because flow around these jets consisted mainly of low velocity vortical events with only partial surface adherence and these low velocity swirling flows were not well imaged by color Doppler technique., Conclusions: Our study suggests that the different-shaped adjacent surfaces with different degrees of flow alterations resulted in variable decreases in jet size and that color Doppler imaging could not encode and image the angled and low velocity swirling events well when jets flowed along the curved surfaces. These effects need to be taken into account when interpreting color Doppler images.

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)

The echocardiographic studies and clinical course of 27 fetuses (mean gestational age 26.9 weeks) diagnosed in utero with tricuspid valve disease and significant tricuspid regurgitation were reviewed. The diagnosis of Ebstein's anomaly was made in 17 of the fetuses, 7 had tricuspid valve dysplasia with poorly developed but normally attached leaflets and 2 had an unguarded tricuspid valve orifice with little or no identifiable tricuspid tissue. One fetus was excluded from data analysis because a more complex heart lesion was documented at autopsy. All fetuses had massive right atrial dilation and most who were serially studied had progressive right-sided cardiomegaly. Hydrops fetalis was found in six cases and atrial flutter in five. Associated cardiac lesions included pulmonary stenosis in five cases and pulmonary atresia in six. Four fetuses with normal forward pulmonary artery flow at the initial examination were found at subsequent study to have retrograde pulmonary artery and ductal flow in association with the development of pulmonary stenosis (n = 1) and pulmonary atresia (n = 3). On review of the clinical course of the 23 fetuses (excluding 3 with elective abortion), 48% of the fetuses died in utero and 35% who were liveborn died despite vigorous medical and, when necessary, surgical management, many of whom had severe congestive heart failure. Of the four infants who survived the neonatal period, three had a benign neonatal course, all of whom were diagnosed with mild to moderate Ebstein's anomaly; only one had pulmonary outflow obstruction. An additional finding at autopsy was significant lung hypoplasia documented in 10 of 19 autopsy reports.(ABSTRACT TRUNCATED AT 250 WORDS)

Normal two-dimensional pulsed Doppler echocardiographic velocity profiles for sites within the heart and great vessels in a group of 102 normal infants and children are presented. Qualitatively, waveforms mimic expected hemodynamic events at the various sites. All waveforms had a rapid initial deflection followed by spectral broadening after attainment of peak velocity. Quantitative angle-corrected peak velocities were generally lower on the right side than on the left side of the heart. Differences in tricuspid (mean 61.8 cm/s) versus mitral (mean 81.1 cm/s) outflow and pulmonary (mean 76.1 cm/s) versus aortic (mean 88.5 cm/s) outflow were significant (p less than 0.01). The only significant age-related differences were in the pulmonary artery (mean for newborns 67.7 cm/s versus 79.6 cm/s for older children, p less than 0.01). Aortic data obtained from interrogation sites in which flow was close to 0 or 180 degrees were similar, whereas aortic peak velocity data obtained from apical long-axis or subcostal views were greater. These differences were probably induced from inaccuracies in azimuthal (elevational) angles that cannot be measured. These normal Doppler data should be useful for comparisons with data obtained for children with various forms of congenital heart disease that affect flow dynamics.

Fourteen patients, aged 1 month to 13 years, with congenital semilunar valve stenosis (11 pulmonary and 3 aortic) were studied for orifice area quantification calculated from a Doppler echocardiographic equation: Area = SV/0.88 X V2 X VET, where SV = stroke volume, V2 = maximal velocity and VET = ventricular ejection time. Results from individual measurements used in this formula and derived area were compared with individual results from cardiac catheterization and valve area derived from the Gorlin formula. Ventricular ejection time by cardiac catheterization ranged from 0.17 to 0.44 second (mean +/- standard deviation [SD] 0.27 +/- 0.09), and by Doppler study from 0.20 to 0.41 second (mean +/- SD 0.29 +/- 0.06) (r = 0.65, standard error of the estimate [SEE] = 0.03, y = 0.149 + 0.528x). Pressure gradient by catheterization ranged from 30 to 125 mm Hg (mean +/- SD 56.6 +/- 33.1), and by Doppler study from 17.6 to 100 mm Hg (mean +/- SD 46.8 +/- 27.9) (r = 0.91, SEE = 8.8, y = 1.23 + 0.904x). Stroke volume was measured by Doppler study simultaneously with cardiac catheterization in nine patients; results at cardiac catheterization with thermodilution measurements (cardiac output/heart rate) ranged from 5.5 to 53.4 cc (mean +/- SD 24.7 +/- 20), and by Doppler study from 5.8 to 46.9 cc (mean +/- SD 23 +/- 18) (r = 0.96, SEE = 3.5). Area quantification was performed in two ways. In Group 1, heart rate-matched stroke volumes from cardiac catheterization were used in the derived equation for Doppler study (all patients). In Group 2, the stroke volume used was that obtained by Doppler study, which was performed simultaneously with cardiac catheterization (nine patients).(ABSTRACT TRUNCATED AT 250 WORDS)

The purpose of this study was to assess the accuracy of continuous wave, two-dimensional Doppler echocardiography for predicting pressure gradients across discrete subaortic stenoses. Twenty-three Newfoundland dogs with subaortic stenosis were studied by closed chest Doppler interrogation of aortic velocity from an apical view of the left ventricular outflow tract simultaneously with measurements of pressure gradient during cardiac catheterization. Continuous mode Doppler interrogation was used with two-dimensional echographic guidance (Irex model IIIB) to compare the Doppler-derived maximal velocity with the pressure gradient across the obstruction at rest and after provocation with amyl nitrite inhalation and isoproterenol infusion. The maximal velocities recorded by Doppler ranged from 98 to 539 cm/s and correlated with hemodynamic gradients ranging from 3 to 123 mm Hg (r = 0.92, SEE = 37 cm/s). Doppler velocities were converted to gradients using a simplification of the Bernoulli relation (gradient = 4 X maximal velocity2); the resulting Doppler-derived gradients also correlated closely with the catheterization-measured pressure gradients (r = 0.95, SEE = 7.1 mm Hg). The predictive capability of Doppler echocardiography for estimating the pressure gradient across fibromuscular subaortic obstructions in this group of dogs with a spectrum of disease similar to that found in human beings was validated. The results also indicate that Doppler methods may have clinical applications in patients with subaortic stenosis.

With the combined use of two-dimensional ultrasound and Doppler echocardiography, noninvasive examination of the human fetal heart and circulation has recently become possible. These techniques were employed to investigate diastolic atrioventricular valve flow in the fetal heart in 120 fetuses studied between 17 and 42 weeks of gestation. Two-dimensional ultrasound was used to examine fetal and intrauterine anatomy, and estimates of gestational age were made based on biparietal diameters and femur lengths. Doppler echocardiography was performed with a 3.5 or 5 MHz Doppler sector scanner. Flow velocity patterns were obtained through the tricuspid and mitral valves during diastole. Peak flow velocity during late diastole or atrial contraction (A) was compared with peak flow velocity during early diastole (E) in four groups of fetuses: Group 1, 17 to 24 weeks of gestation; Group 2, 25 to 30 weeks; Group 3, 31 to 36 weeks; and Group 4, 37 to 42 weeks. The ratio of A to E decreased significantly as gestational age advanced, from 1.56 +/- 0.06 (+/- SE) to 1.22 +/- 0.03 across the tricuspid valve (p less than 0.001) and from 1.55 +/- 0.04 to 1.22 +/- 0.06 across the mitral valve (p less than 0.001). In tricuspid valve measurements, peak flow velocity during early diastole increased from 26.3 +/- 2.0 cm/s in Group 1 to 36.5 +/- 1.7 cm/s in Group 4 (p less than 0.001), whereas peak flow velocity during atrial contraction did not change.(ABSTRACT TRUNCATED AT 250 WORDS)

Results of two-dimensional echocardiographic examinations were compared with angiographic, hemodynamic and surgical results in 44 patients with bioprosthetic valves in mitral and aortic positions who were undergoing elective or urgent reinvestigation 24 to 87 months (mean 34) after implantation. In these patients, there were 18 homograft aortic valves in the aortic position, 9 stent-mounted homograft aortic valves in the mitral position, 13 porcine xenograft valves in the mitral position and 12 in the aortic position. Poor cusp support, gross fluttering and prolapse of cusps behind or below the anulus identified aortic insufficiency by two-dimensional echocardiography in six patients with an aortic homograft and four patients were identified with insufficiency of a stent-mounted aortic homograft in the mitral position. Two-dimensional echocardiographic examination revealed mitral stenosis in three patients with a porcine xenograft valve in the mitral position and suggested mitral insufficiency in two others. Bacterial endocarditis on homograft or porcine xenograft valves was associated with easily imaged vegetations by two-dimensional echocardiography in 10 patients. Despite difficulties in imaging valve cusps, and the skill required to obtain good echocardiographic images of bioprosthetic valves, significant valve deterioration or infected prostheses were quite effectively imaged by two-dimensional echocardiography in this study.

Technical considerations and the instrumentation used for pediatric two-dimensional echocardiography and Doppler examination are reviewed. The configurations of sector scanners, the function of the mechanical versus phased array systems and considerations related to lateral, axial and azimuthal resolution requirements are discussed. The performance and requirements for echocardiographic cardiographic scan converters and the requirements for pediatric display are reviewed. Methods of performing quantitative Doppler echocardiography are discussed because this technique provides new and important types of information for the evaluation of congenital heart disease. Considerations of Doppler velocity, Doppler spatial resolution and Doppler display requirements are presented. Characteristics of ultrasonic imaging devices for use in fetal echocardiography and fetal Doppler study are reviewed, and a brief overview of techniques for the extraction of information about the nature of ultrasound scatterers (that is, tissue signature) is presented. It is the purpose of this technically oriented discussion to present the capabilities, trade-offs and needs for future development relevant to pediatric echocardiography in 1983.

Contrast echocardiography has achieved importance in the diagnosis of cardiac shunt lesions. The technique provides information about flow patterns and serves as an adjunct to identifying communications that may be too small to image, even with high resolution real time scanning. This report reviews clinical applications and experiences in the use of standard, peripherally injected echocardiographic contrast agents for the detection of atrial septal defect, ventricular septal defect and patent ductus arteriosus. The importance and development of transpulmonary contrast agents capable of crossing the pulmonary capillary bed to opacify the left ventricle are reviewed and experience with a variety of experimental echocardiographic contrast agents is presented. Agents opacifying the left ventricle after intravenous injection are capable of providing direct ultrasonic contrast imaging of congenital left to right shunts. Further, recent experience with an experimental standardized, gas-producing contrast agent in an open chest animal model with an experimentally produced ventricular septal defect suggests that a combination of an experimental right heart agent that produces a measurable and reproducible amount of contrast effect, with a videodensitometric system capable of quantifying both positive and negative contrast effects, may provide an ultrasonic method for evaluating the magnitude of cardiac shunts.