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Hearts in which the arterial trunks arise from the morphologically appropriate ventricles, but in a parallel manner, rather than the usual spiralling arrangement, have long fascinated anatomists. These rare entities, for quite some time, were considered embryological impossibilities, but ongoing experience has shown that they can be found in various segmental combinations. Problems still exist about how best to describe them, as the different variants are often described with esoteric terms, such as anatomically corrected malposition or isolated ventricular inversion. In this review, based on our combined clinical and morphological experience, we demonstrate that the essential feature of all hearts described in this manner is a parallel arrangement of the arterial trunks as they exit from the ventricular mass. We show that the relationship of the arterial roots needs to be described in terms of the underlying ventricular topology, rather than according to the arrangement of the atrial chambers. We then discuss the importance of determining atrial arrangement on the basis of the morphology of the appendages, following the precepts as set out in the so-called “morphological method” and distinguished according to the extent of the pectinate muscles relative to the atrioventricular junctions as opposed to basing diagnosis on the venoatrial connections. We show that, when approached in this manner, the various combinations can be readily diagnosed in the clinical setting and described in straightforward way.

Background: Disagreement currently exists regarding the definition of aortic dextroposition. It is suggested that the term be used interchangeably with aortic overriding, along with suggestions that the aortic valve overrides in the normal heart. The dextroposed aorta, however, does not always override the crest of the muscular ventricular septum. It is incorrect to argue that the normal aortic valve overrides. It is the cavity of the right aortic valvar sinus, rather than the valvar orifice, that sits above the muscular septum when the septum itself is intact. Therefore, to circumvent these difficulties, those using the term “dextroposition” find it necessary to distinguish “true” as opposed to “false” categories. The problems arise because “dextroposition” is remarkably ill-suited as an alternative term for aortic valvar overriding.Methods and Results:In this review, combining developmental, morphologic, and clinical data, we show how aortic overriding is best considered on the basis of biventricular connection of the aortic root in the setting of deficient ventricular septation. When analysed in this manner, it becomes an easy matter to distinguish between one-to-one and double outlet ventriculo-arterial connections. Appreciation of these features emphasises the different spatial alignments of interventricular communications as opposed to the plane of deficient ventricular septation. The concept of overriding is applicable not only to biventricular connection of the aortic root, but also the pulmonary and common arterial roots.Conclusions:The diagnostic techniques now available to the paediatric cardiologist illustrate the features of arterial valvar overriding with exquisite accuracy, informing the discussions now required for optimal decision making.

It is frequent, in the current era, to encounter congenital cardiac malformations described in terms of “cor triatriatum”. But can hearts be truly found with three atrial chambers? The morphological method, emphasised by Van Praagh et al, states that structures within the heart should be defined on the basis of their most constant components. In the atrial chambers, it is the appendages that are the most constant components, and to the best of our knowledge, hearts can only possess two appendages, which can be of either right or left morphology. The hearts described on the basis of “cor triatriatum”, nonetheless, can also be analysed on the basis of division of either the morphologically right or the morphologically left atriums. In this review, we provide a description of cardiac embryology, showing how each of the atrial chambers possesses part of the embryological body, along with an appendage, a vestibule, a venous component, and a septum that separates them. We then show how it is, indeed, the case that the hearts described in terms of “cor triatriatum” can be readily understood on the basis of division of these atrial components. In the right atrium, it is the venous valves that divide the chamber. In the left atrium, it is harder to provide an explanation for the shelf that produces atrial division. We also contrast the classic examples of the divided atrial chambers with the vestibular shelf that produces supravalvar stenosis in the morphologically left atrium, showing that this form of obstruction needs to be distinguished from the fibrous shelves producing intravalvar obstruction.

BACKGROUND Knowledge of right ventricular (RV) shape is important to the understanding of RV mechanical function and for the improvement of clinically important RV volume estimation techniques. Refinements to the simplest conceptions of RV shape are presented statistically here, based on a quantitative analysis of three-dimensional magnetic resonance (MR) images of excised lamb hearts. METHODS The passive shape of the heart in six freshly excised lamb hearts was studied with MR imaging with independent passive pressurization of both ventricles. Global features of shape were assessed, including measurement of short-axis, cross-sectional shape parameters associated with the pinched-arc model. RESULTS The slice-area x apex-base length was found to be highly correlated with the volume of the RV, with little sensitivity to the degree of filling of the ventricle or to the exact slice chosen (r = 0.987; n = 22 from five hearts). The RV was shown to follow a clockwise helical path around the left ventricle of 47 +/- 17 degrees, below the outflow tract, as seen from the apical view, progressing from the apex to the base. Based on the pinched-arc model, the anterior arc is shallower than the posterior arc, with a larger radius of curvature and a smaller angle between the arc and the septal axis. As the RV is passively filled, opposite changes in shape occur between the anterior and posterior regions tending to equalize their shapes. CONCLUSIONS A high degree of regularity of shape does exist in the RV and, thus, can be characterized effectively in terms of a representative cross-sectional shape and in terms of the changes in that shape proceeding from the base to the apex.

Background. There are few congenital anomalies of the heart that have benefited more from thorough anatomic analysis than the complex anomaly known as atrioventricular septal defect in the setting of common atrioventricular junction. Recent advances in understanding the anatomy of this lesion have led to alternative methods of repairing these defects. Methods. The medical records of 21 consecutive patients undergoing repair of complete atrioventricular septal defect have been reviewed. Nine of these patients had a standard one- or two-patch repair, and 12 had direct closure of the ventricular element of the defect. Results. Direct closure resulted in significantly shorter pump and cross-clamp times. Follow-up for an average of 34 months suggests that when direct closure can be performed, the results are comparable with those of the more standard technique. Conclusions. Our initial success with this approach is encouraging; however, longer follow-up is required to establish whether it will be broadly applicable.

The determinants of right ventricular (RV) performance with damaged RV free wall, such as occurs with RV infarction, are still unclear. Using 20-MHz Doppler ultrasound equipment, we investigated the changes in pulmonary blood flow velocity profiles before and after ligation of the right coronary artery. RV dp/dt, stroke volume, RV stroke work, aortic pressure and cardiac output decreased and central venous pressure rose after the ligation. The RV stroke work-end-diastolic pressure relationship indicated impaired RV function following ligation. We observed shortened acceleration time (65.0 +/- 15.1 vs 54.4 +/- 6.2 ms, P0.05) and reduced maximum velocity of forward flow (59.0 +/- 5.9 vs 52.5 +/- 7.6 cm/s, P0.05) after the ligation. Acceleration was interrupted earlier after ligation than before ligation. These alterations in flow are thought to be a consequence of the altered movement of the RV free wall and ventricular septum induced by RV infarction.

M edical discoveries, no matter how brilliant, cannot improve clinical care unless they are actually used. The marketplace is the instrument by which medical products are provided to patients who need them. In North America, the development of new medical products to the point of marketing is both highly regulated and highly competitive. Both the development and initial marketing of any medical innovation are difficult challenges in themselves, but the difficulties involved are probably a logfold greater for new pharmaceutical products than for new items of medical equipment, because far tighter regulatory hurdles are imposed by the Food and Drug Administration (FDA) and Health Protection Branch (HPB), respectively, in the USA and Canada for new drugs. Randomized clinical trials are the safest, most ethical, and most efficient mechanism for introducing innovations to all areas of clinical medicine, including perinatal practice. Successful commercialization of such innovations requires ei ther the direct or indirect sponsorship of well established commercial enterprises. These enterprises must have the requisite capital, technical resources, and knowledge to produce the innovation reliably, to evaluate the innovation in the clinic in a rigorous manner, to secure the necessary regulatory approvals, and to market the innovation successfully. Whether a potential innovation for perinatal practice ever reaches industry-sponsored clinical trials, much less the perinatal market, is determined by the interplay o f a wide variety of forces. This article will review the role of industrysponsored clinical trials in improving perinatal

The distribution of axial velocities in the pulmonary artery must be determined to describe accurately the flow in the pulmonary artery. Previous studies in our laboratory have demonstrated the complexity of the velocity profile in the pulmonary trunk and the branch pulmonary arteries with normal and altered pulmonary blood flow. These findings have demonstrated a skewed, parabolic mean velocity profile in the pulmonary trunk under normal hemodynamic conditions. To determine the effect of left-to-right intracardiac shunting on the distribution of axial velocities in the pulmonary artery, an animal model of atrial and ventricular shunting was used. In both models, the distribution of mean axial velocities remained skewed and parabolic with the higher mean velocities recorded toward the anterior wall.

To provide a comprehensive picture of the interaction between abnormal pulmonary hemodynamics and pulmonary blood velocity patterns in the young, we have developed infant animal models of pulmonary hypertension and/or elevated pulmonary blood flow. This report focuses on relationships between selected velocity waveform shape-dependent variables — i.e., the time between the onset of systole and peak velocity (rise time), the time during which velocity remains at >90% of that peak (90% time), and flow reversal patterns — and traditional hemodynamic indications of pulmonary vascular impairment, i.e., elevated pulmonary artery pressure and pulmonary vascular resistance. Studies were performed on 36 anesthetized, open-chest, one-month-old lambs with normal pulmonary circulations or with abnormal conditions that had been initiated during the first few days of life via (1) a central venous injection of monocrotaline pyrrole (hypertension) or (2) a side-to-side anastomosis between the common carotid artery and jugular vein (elevated flow). Animals with large shunts (shunt open cardiac output/shunt closed cardiac output >2.1) had both elevated pressures and flows. The tightest correlations (linear and log-linear) were found between unindexed pulmonary vascular resistance and waveform variables, the most reliable being 90% time (r = −0.838), 90% time + rise time (r = −0.838), and 90% time × rise time (r = −0.824). The best correlate to mean pulmonary artery pressure was 90% time + rise time (r = −0.713). Combined rise time and 90% time variables yielded results that exceeded 90% sensitivity and specificity levels in diagnosing elevated pulmonary vascular resistance (>700 dyne-sec/cm5). Absence of flow reversal in central and anterior regions was an indicator of markedly elevated pulmonary artery pressures (mean >28mmHg). The findings of this report (1) demonstrate the successful development of animal models that mimic a broad spectrum of relevant pulmonary hemodynamics in infants and children with compromised pulmonary circulations and (2) point to shape variables that should improve noninvasive assessment of elevated pulmonary vascular resistance.

To study the effect of maturational geometric changes on flow characteristics in the pulmonary artery trunk, anatomically accurate, acrylic flow-through models were constructed from four flexible silicone rubber casts obtained in situ in lambs weighing 2.4, 7.8, 9.5, and 11.5 kg. A silicone rubber cast of the right heart was fabricated by injecting the superior caval vein in situ with liquid silicone rubber (Dow Corning's HS-II RTV, Midland, MI). Each cast was used as a template for a transparent acrylic mold of the pulmonary artery trunk and primary generation branches. The acrylic block was then fitted with a curved rigid Plexiglass inflow tube (to simulate the curvature of the right ventricle) just proximal to the pulmonary valve sinuses and mounted in a closed loop system driven by a variable speed pulsatile pump (to simulate physiological flow rates between 0.5 and 4.0 lmin−1) A blood analog solution of polystyrene beads (Rohm & Haas Amberlite, Philadelphia, PA) suspended in a 45% by weight glycerine solution was illuminated by a laser source (15 mwatts, Siemens, Germany) to trace the flow patterns. Two flow field planes of the main pulmonary artery trunk—one parallel, and one perpendicular, to the origins of the right and left arterial branches—were visualized and video recorded (Canon H660 8mm, Japan) for subsequent analysis. A prominent vortex, originating in the center of the main pulmonary artery and directed inferiorly toward the inner wall, was noted in the flow field plane perpendicular to the bifurcation in the 9.5 and 11.5 models. These characteristics were less developed in the 7.8 kg model and not present in the 2.4 kg model, possibly because the angle of curvature was less acute than in the larger models. In the flow field plane parallel to the bifurcation, the patterns were more complex, principally influenced by turbulence in the main pulmonary artery (which increased at higher flow rates) and the geometric changes in the branch pulmonary arteries.

Surgical banding of the pulmonary artery in patients with transposition of the great arteries leads to a rapid increase of the left ventricular mass. The purpose of this animal experiment was to induce ventricular systolic hypertension in the “subpulmonary ventriclerdquo; by intravascular obstruction to pulmonary flow. The first experiment was performed in an anesthetized animal with an open thorax. A balloon-tipped catheter was introduced into the femoral vein and advanced to the pulmonary artery. The balloon was positioned in the pulmonary trunk and was progressively inflated until a systemic pressure was achieved in the “pulmonary ventricle”. This was accomplished within 40 minutes without a significant reduction in cardiac output, which was continuously monitored by an electromagnetic flowprobe. In the second experiment an analogous procedure was performed in a closed chest, awake, spontaneously breathing animal. The catheter was maintained in proper place for 24 hours. Subsequent macroscopic examination of the heart demonstrated a remarkable increase in the ventricular mass. The results of this preliminary experiment demonstrate the possibility for creating “intraluminal pulmonary banding”. The potential advantages of this technique are the nonsurgical approach and the ability to adjust the grade of obstruction to pulmonary flow.

The use of an obstructing balloon catheter positioned in the outflow tract of the pulmonary ventricle may be an alternative method for the adaptation of the left ventricle to an increased afterload prior to an arterial switch procedure in patients with complete transposition requiring a two-stage approach. We tested this approach in an acute hemodynamic study in a piglet model. Seven piglets were anesthetized with halothane and ventilated at FiO21.0. Through a median sternotomy, the great vessels were exposed. The right ventricular pressure and the aortic blood pressure were recorded using microtip manometers, cardiac output was measured by an electromagnetic flow probe on the ascending aorta. A 6F or 7F Berman angiographic catheter was placed in the lumen of the pulmonary artery and the balloon inflated to decrease cardiac output no more than 30%. The hemodynamic changes observed after balloon inflation included an 100% increase in systolic right ventricular pressure (control vs balloon inflation (mean±SE) 20.4 ± 1.5 mm Hg vs 46.6 ± 4 mm Hg, p

SummaryDefects of the atrioventricular septum impose changes in the septal architecture, atrioventricular valves, and conduction system that must be well understood for optimal repair. The atrioventricular node and bundles are shifted to more posterior and inferior positions that can be anticipated by the surgeon so as to maintain the integrity of atrioventricular conduction. The atrioventricular valve is a five leaflet structure that possesses a common orifice or separate orifices depending on characteristics of the superior and inferior bridging leaflets. These features are demonstrated by intraoperative photographs viewed from the surgeon's position.

The velocity pattern of the blood flow in the pulmonary artery was investigated in an animal model of acute pulmonary hypertension. Nine anesthetized, open-chest dogs were embolized with polystyrene microspheres, and the velocity pattern of the blood flow in the pulmonary artery was studied with use of an invasive pulsed Doppler technique. Phasic intraluminal velocity was recorded with use of a miniature piezoelectric crystal activated by 20-MHz Doppler pulses and mounted on the tip of a needle probe introduced into the pulmonary artery. The recorded Doppler quadrature signals were processed by spectral analysis. Significant increases occurred in mean, systolic, and diastolic pulmonary arterial pressures (p less than 0.0002), in pulmonary vascular resistance (p less than 0.005), and in negative velocity time (duration in milliseconds that the mean velocity was directed toward the pulmonic valve) (p less than 0.002). Significant decreases occurred in right ventricular ejection time (p less than 0.006) and in positive velocity time (duration in milliseconds that the mean velocity was directed away from the pulmonic valve) (p less than 0.005). A significant shortening in the time to peak velocity (acceleration time) was found (p less than 0.005). Second-order regression analyses demonstrated an inverse correlation between the ratio of positive velocity time to negative velocity time and the mean pulmonary artery pressure in all animals (r = 0.71). These findings should be compared with the velocity patterns of the blood flow in the pulmonary artery obtained under pulmonary hypertensive conditions due to various causes to facilitate interpretation and understanding of clinical investigations.

SummaryComplete transposition is a morphologic entity which exists by virtue of a concordant atrioventricular connection co-existing with a discordant connection at the ventriculoarterial level. If diagnosed in this manner, all variants can be described simply and unambiguously in terms of associated malformations along with variations in relationships and infundibular morphology.

The coronary sinus is an important landmark for the position of the atrial component of the atrioventricular conduction axis and, thus, assumes special relevance to the surgeon in the operating room. We describe here 2 patients with atrioventricular septal defect characterized by an unusual termination of the coronary sinus within the left atrium. We discuss the potential importance of this finding to the disposition and surgical avoidance of the conduction tissues.

Los defectos congenitos ocurren aproximadamente en el 2% de todos los nacimientos. La cardiopatia congenita corresponde casi a la mitad de estos defectos, y ocurre aproximadamente en 8 de cada 1.000 recien nacidos. Existen muchas clasificaciones para las cardiopatias congenitas. A continuacion presentaremos dos variedades que siguen un enfoque fisiologico simple.

La toma de imagenes cardiacas en multiples planos mediante la ecocardiografia puede definir de forma no invasiva la anatomia del corazon y de los grandes vasos, delineando la configuracion y la posicion de las estructuras cardiacas y las interrelaciones espaciales de estas estructuras. La informacion obtenida puede ser utilizada para establecer un diagnostico preciso y un pronostico en las cardiopatias congenitas complejas. En muchos centros de cardiologia pediatrica de tercer nivel, la ecocardiografia es la unica prueba diagnostica realizada antes de la cirugia neonatal de las cardiopatias congenitas. Con los avances como la ecocardiografia Doppler pulsada y en color, y las mejoras en el tamano y la capacidad de los transductores y otros equipos de imagen, la ecocardiografia pediatrica ha obtenido una aceptacion rapida. La tecnologia permite la toma de imagenes tridimensionales en tiempo real, la evaluacion de la funcion miocardica y la definicion exacta de la anatomia cardiaca desde la etapa fetal hasta la edad adulta. Por todos estos motivos, la ecocardiografia se ha convertido en la modalidad estandar de la obtencion no invasiva de imagenes diagnosticas en cardiologia pediatrica.

Nuestros conocimientos sobre las complejidades de las cardiopatias congenitas, una desviacion del desarrollo anatomico normal del corazon que afecta a 8 de cada 1.000 recien nacidos, han avanzado enormemente desde el establecimiento del Board of Pediatric Cardiology (y por consiguiente la subespecialidad) en 1961. Los avances han sido paralelos al perfeccionamiento de las tecnicas de imagen diagnosticas, como la ecocardiografia y la angiografia cardiaca, y las innovaciones en las tecnicas de reparacion quirurgica. La investigacion cientifica basica ha permitido comprender mejor los patrones del desarrollo embriologico y de las anomalias causantes de las alteraciones congenitas frecuentes. Este capitulo aborda con cierto detalle la genesis de las cardiopatias congenitas, centrandose en el papel de las intervenciones quirurgicas correctoras.

A quantitative characterization of the shape of the right ventricle (RV) of the heart is needed for accurate modeling of the mechanics of the ventricle as well as for better measuring the volume of the ventricle from technologies such as 2D ultrasound, bi-planar ventriculography, and sonomicrometry. A technique was thus developed for modeling RV shape. First, a high-resolution MR image set was obtained of the freshly excised lamb heart under various passive pressurizations of both ventricles ranging from 5 to 30 cmH2O simulating end-diastole in the beating heart. Typically, 2-3 full images were obtained for each heart. Images were obtained with a multislice spin-echo T1-weighted sequence with the slice plane orientation early equal to the short-axis view of the heart. A 3D characterization of shape was obtained by first characterizing inter-slice changes in shape and orientation and then characterizing the shape of a single representative slice. The slice chosen to represent the RV was in the region directly below the tricuspid valve since it is both near to the apex-base center of the RV and has the greatest size. Intuitive deformations were applied to an initial circular arc anchored at the endpoints of the freewall and initially passing through a point near the center of the freewall contour, so as to best match the true freewall contour. These include a leaning of the circular arc parallel to the septal axis, a flattening perpendicular to the septal axis, a tucking-in or sharpening of the curvature near the junction with the septum, and a pinching- in at a point or points near its center towards the septum, all, in an attempt to account for the asymmetry and non- circularity deformed circular arc which effectively produces tow independent arcs. For all but one of the anterior and posterior arcs in 13 heart shapes, pinch-deformed arcs could be obtained whose average radial distance from the true RV chamber contour was less than 0.9 mm and averaged 0.5 mm for the anterior arc and 0.66 mm for the posterior arc. Worst- case deviation in parameters of the pinched-arc model of cross-sectional shape, and radii of curvature and the RV freewall-septum junction angle due to worst-case deviation in landmark location are 19 percent +/- 11 percent, 10 percent +/- 6 percent, 10 degrees +/- 4 degrees, and 12 degrees +/- 6 degrees. If landmark localization variability is minimized with a rigid translate offset scale model of the landmark region, average measurement error as determined in an adjacent slice comparison was 11 percent +/- 5 percent, -3 percent +/- 2 percent, 7 degrees +/- 2 degrees, and -7 degrees +/- 2 degrees.© (1997) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

When percutaneous vascular access for cardiac catheterization of small infants fails, necessitating a cutdown approach, we cannulate the isolated vein (usually the great saphenous vein) with a guidewire, dilator, and sheath with subsequent introduction of the catheter through the indwelling sheath. We have used this technique in sixty-one infants without complications and recommend this modified sheath approach because of the following advantages: ease of introduction of the introducer set and catheter, the ability to change catheters quickly, elimination of distal vascular spasm, reduction of vascular trauma induced by catheter manipulation, prevention of backflow bleeding at the catheter entry site, and possible reduction of catheterization time.

We hypothesized that infradiaphagmatic total anomalous pulmonary venous drainage (ITAPVD), because of its unique physiology, could be diagnosed with radionuclide angiography. Seven neonates with severe respiratory distress were injected intravenously with 3 mCi technetium-99m pertechnetate. In each of four neonates demonstrated to have ITAPVD by pulmonary angiography, nuclide recirculation through the right atrium occurred 3-6 s after initial passage. In addition, direct visualization of the anomalous common pulmonary trunk with nuclide as a "tail" below the diaphragm was obvious in the third infant studied. This prompted review of the first two infants with ITAPVD; in retrospect the anomalous trunk was also visualized with nuclide in both of these infants. All three were injected via the upper extremity. In the fourth ITAPVD infant, nuclide was injected via the lower extremity. In that infant, preferential streaming of the inferior vena caval flow and nuclide across the foramen ovale into the left heart led to simultaneous opacification of anomalous trunk and descending aorta, obscuring the "tail" sign.

Clinical investigations focused on finding characteristics of noninvasively obtained measurements of pulmonary blood velocity that can be used to quantitate pulmonary blood flow and/or pulmonary pressure have often yielded results whose imprecision has been attributed to flow pattern variability. To determine flow pattern variability in an in vivo animal model in varying hemodynamic states, main pulmonary artery blood velocity waveforms were recorded in 17 dogs at 2-mm intervals along an anterior to posterior wall-oriented axis using a 20-MHz pulsed Doppler needle probe. Control data were obtained before the animals were subjected to altered flow (atrial level shunts) and pressure (10% O2 inhalation) states. Instantaneous velocity profiles were computed throughout the cardiac cycle. Estimates of pulmonary blood flow were obtained assuming an elliptical model of the pulmonary artery which allowed computation of velocity at all points in the cross section, based on the measured values along the axis. Model-based estimates were compared to measured values and estimates obtained in the traditional fashion, i.e., the product of centerline velocity and cross-sectional area. Results clearly showed marked interanimal variability, even in control states. Reverse flow in the posterior half of the vessel, which tended to become more pronounced with increased pulmonary artery pressure, was observed during late systole and early diastole. Elevated pulmonary blood flow tended to increase the maximum velocities along the anterior wall relative to midline velocities. Neither estimate of cardiac output yielded consistently accurate results (r = 0.77 for model-based method, r = 0.80 for area times central velocity method). Findings of this study, which highlight the dependency of waveform characteristics on sampling site, the large degree of intersubject variability, and the need for large or multiple sample volumes for pulmonary blood flow determination, help clarify inconsistencies observed by clinicians and suggest that future work with animal models will facilitate a greater understanding of the determinants of human pulmonary velocity waveforms.

Systemic pulmonary shunts are both surgically created (Blalock-Taussig anastomosis) and obliterated (patent ductus arteriosus), but the effects of such a vascular communication on left ventricular hemodynamics have not been examined quantitatively. To study these effects, innominate arterial allografts were sutured between the descending thoracic aorta and the left main pulmonary artery in nine mongrel dogs. Left ventricular output (LVO) and shunt flow (SF) were monitored with electromagnetic flow probes while simultaneous phasic and mean pressures were recorded from the right atrium, aorta (AOP), and pulmonary artery. Data points (192) were analyzed while SF was varied between 0.02 and 5.5 liters/min using a variable-sized constricting band. Regression analysis showed increases (P less than 0.01) in LVO, stroke work (SW), and stroke volume (SV) in all dogs which were linearly related to SF (r = 0.64-0.99). Increasing SF was also associated with decreases (P less than 0.01, r = 0.61-0.99) in resistance (RES) facing the left ventricle and in diastolic (D) AOP. To compensate for differences in allograft size and to quantify the effects of a patent shunt, the regression equations were used to compare the percentage change in all parameters at SF = 0 and SF = 1.5 liters/min. Increases occurred in SV (46 +/- 21%), SW (32 +/- 14%), and LVO (48 +/- 21%), and decreases were present in DAOP (15 +/- 12%) and RES (32 +/- 13%). These data show that despite the decreases in pressure or the decreases in resistance facing the left ventricle in the presence of a systemic pulmonary shunt, a substantial increase in stroke work occurs.(ABSTRACT TRUNCATED AT 250 WORDS)

After being struck by an automobile, a 9 year old boy developed transient right bundle branch block followed by electrocardiographic changes of inferior wall myocardial infarction and an increase of serum cardiac enzymes. Two-dimensional echocardiography demonstrated a prominent septal aneurysm. Subsequent cardiac catheterization confirmed septal aneurysm and demon- strated an additional inferior aneurysm. Six weeks after the accident, resection of the inferior aneurysm was performed. At 1 year follow-up study, residual septal aneurysm and cardiomegaly are present, but the boy is asymptomatic.

Nondepolarizing muscle relaxants are being used with increasing frequency in neonatal intensive care units. However, information concerning the chronic use of these agents and their dose requirements of d-tubocurarine and metocurine in neonates in whom respiratory paralysis was used as an adjunct to mechanical ventilation. All infants with gestational age greater than or equal to 38 wk demonstrated a dramatic daily increase in dose requirement of metocurine during the initial 8 days. However, infants with gestational age greater than or equal to 33 wk did not demonstrate a statistically significant daily increase in dose requirement. The 4 infants who received metocurine for more than 10 days exhibited a plateau of the dose requirement after 8-10 days. In contrast to the infants receiving metocurine, infants who received d-tubocurarine did not demonstrate a significant change in daily dose requirement. Four infants who received metocurine and four who received d-tubocurarine had acute renal failure and were not included in the above analysis. These infants had a significantly decreased dose requirement compared to the expected dose requirement for infants of comparable gestational age. There was no relationship between the dose requirement and the pH, serum potassium, or the use of aminoglycoside antibiotics.

To determine whether pulmonary vascular disease can be detected in infants with ventricular septal defect (VSD) by the presence of an increase in the frequency of the impedance modulus minimum of the pulmonary input impedance spectrum, as has been implied for older children, spectra of 25 infants (2 years or younger) (group 1) were compared with spectra of 20 children (ages 2 to 7 years) (group 2). Groups were subdivided according to mean pulmonary artery (PA) pressure: those with moderate pressure levels (35 mm Hg or less, groups 1A and 2A) and those with high pressure levels (at least 40 mm Hg, groups 1B and 2B). Pulmonary vascular resistance, characteristic impedance and frequency of the modulus minimum were significantly lower in group 2A than in group 1A. The decrease in pulmonary vascular resistance and characteristic impedance with increasing age was consistent with body surface area increases; however, the shift in frequency of the modulus minimum could be more easily related to a decrease in the pulse wave velocity than to a shift in the primary reflection site. Pulmonary vascular resistance, characteristic impedance and the frequency of the first modulus minimum were comparable in groups 1B and 2B; however, none of the patients in group 1B had evidence of pulmonary damage, whereas 3 of 4 group 2B patients had microscopically apparent pulmonary vascular disease. This evidence suggests that the importance of a shift in the frequency of the modulus minimum is dependent on patient age and characteristic impedance and that elevated characteristic impedance may indicate a slowing of the normal developmental process of proximal pulmonary vessels, which serves as a temporary protective mechanism for the peripheral pulmonary vascular bed.

A 1-month-old male child with a previously placed ventriculoatrial catheter presented with severe cardiorespiratory distress secondary to cardiac tamponade. A cerebrospino-pericardial communication from right atrial perforation by the catheter was diagnosed quickly and easily by a radionuclide injection of the proximal shunt reservoir.

Left ventricular outflow tract obstruction is a particularly vexing problem in patients with complete transposition (atrioventricular concordance and ventriculoarterial discordance) and intact ventricular septum. Previous techniques, such as resecting the obstructive lesion through the pulmonary valve or bypassing the obstruction, have not given entirely satisfactory results. An alternative approach of resection through the left atrium and the retracted mitral valve has recently been proposed. We have used this new technique to achieve excellent relief of this condition in three patients with different types of obstruction.

Little is known regarding the hemodynamic effect of positive end-expiratory pressure (PEEP) following pneumonectomy. To investigate this, 9 mongrel dogs underwent PEEP before and after lung resection. With the chest closed, the dog anesthetized, and partial pressure of carbon dioxide constant, PEEP was added in increments of 2 mm Hg until the animal's condition became hemodynamically unstable. At each level of PEEP, aortic, pulmonary, left atrial, and central venous pressures were monitored while aortic flow (cardiac output) was determined with an electromagnetic probe and airway pressure was measured with a Millar catheter in the respiratory tubing. Pneumonectomy was then performed, PEEP was again sequentially added, and the same measurements were recorded. Both before and after pneumonectomy, a strong positive linear correlation exists between the level of PEEP and pulmonary vascular resistance (PVR) (r greater than 0.74; p less than 0.05). Also, there is a high negative linear correlation between the level of PEEP and cardiac output (r greater than -0.76; p less than 0.05). At 0 mm Hg of PEEP, the PVR is higher after pneumonectomy than before (p less than 0.02). The incremental elevation in PVR persists after pneumonectomy at each level of PEEP, and in 5 of the 9 dogs the slope of the linear regression line relating PVR to PEEP was steeper following resection (p less than 0.05), thereby demonstrating an exaggerated effect of PEEP on PVR. In addition, all animals had a lower cardiac output at each comparable level of PEEP following pneumonectomy (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

A 5-week-old infant presented with signs of severe congestive heart failure and pulmonary hypertension. Injection of technetium-99m pertechnetate demonstrated anomalous perfusion of the right lung. Subsequently, anomalous origin of the right pulmonary artery from the ascending aorta was proven at cardiac catheterization and repaired. Repeat injection of radionuclide 1 week postoperatively demonstrated normal flow to the right lung.

The nonsynchronous respiratory efforts of neonates with surgically correctable disorders may inhibit effective mechanical ventilation. The records of 25 infants treated with metocurine for muscular paralysis to improve mechanical ventilation were reviewed. All patients were greater than 35 (37.6 +/- 2.1) weeks gestation and 2.27 (2.98 +/- .47) kg. All required ventilatory support with an FiO2 of 100%. The mortality rate of this group of infants was 20% as compared with 73% (p.001) in a similar group of 26 infants managed without paralysis. In 10 of the 25 infants treated with metocurine, pre- and 1 hr postparalysis paO2 values were available. The mean paO2 prior to paralysis was 62 (45--111) mm Hg and the mean post-paralysis paO2 was 144 (75--227) mm Hg, representing at 132% increase in paO2 (p.001). The mean dosage for metocurine was 3.5 (1.45--6.79) mg/kg/day; however, those requiring paralysis for greater than 7 days showed a dramatically increasing requirement. These preliminary data suggest that respiratory paralysis reduces right-to-left shunting, improves paO2 and decreases mortality in large infants with severe respiratory distress requiring ventilatory support.

Newborns with severe obstruction to pulmonary blood flow may depend on the persistence of a patent ductus arteriosus for the maintenance of adequate systemic oxygenation. In an attempt to preserve ductal patency 19 infants have received PGE1 (prostaglandin E) since February 1977. The infusions were made into the scalp vein begun anywhere from 24 hours to 3 days with a varied duration of 5 hours to intermittently over 13 days. Dosages ranged from 0.025-0.3 mcg/kg/minute. All 19 displayed a marked rise in blood oxygen with the difference prior to PGE2 administration (mean of 25) and post-PGE1 administration (mean of 52) being highly significant (P > 0.001). Cardiovascular side effects such as arrhythmias or systemic hypotension were not noted. However 5 infants did suffer from mild pyrexia 2 had seizures and occasional flushing. No deaths were reported prior to or during the 26 surgical procedures and 10 infants have survived for 3-19 months. Indications are that PGE1 administered by a peripheral vein is effective in maintaining ductal patency in newborns displaying right ventricle outflow obstruction. (Authors modified)