Intravascular ultrasound image subtraction: a contrast enhancing technique to facilitate automatic three-dimensional visualization of the arterial lumen.

At 30 MHz, the intravascular ultrasound backscatter of blood confounds the discrimination of the lumen from the arterial wall. This study validates a subtraction method which creates a still-frame image with a sharp demarcation of the lumen. The method involves subtraction of consecutive images and 2D ensemble averaging of the absolute pixel values. Subtraction exploits the dynamic properties of flowing red blood cells. Three phantom arteries were used, with erythrocytes in their lumens and wall. For this reason, it was not possible, in one single original image, to discriminate the blood in the lumen from the phantom wall. Based on 26 consecutive original images, in the mean subtraction image contrast between lumen and phantom wall grey values increased eightfold from 10.9 (5.3-19.2) (mean and range) in the original image to 87.7 (73.6-107.0) (P < 0.001). A sufficiently large contrast increase to allow automatic segmentation was obtained by using five original images (0.3-s acquisition time) for any single mean subtraction image. Low blood flow velocities (down to 0.5 cm/s) did not alter this result. Automatic segmentation of the lumen allowed fast 3D reconstruction of the lumen in all three phantom arteries. In phantom arteries, the intravascular ultrasound image subtraction technique improved contrast between lumen and wall which enabled automated lumen segmentation and fast 3D visualization of both the lumen and defects in the wall.

Complete right bundle branch block after surgical closure of perimembranous ventricular septal defect. Relation to type of ventriculotomy.

The ECGs of a 100 consecutive children who had surgical repair of their ventricular septal defects (VSDs) were analyzed for postoperative right bundle branch block (RBBB). Seventy of them had an atriotomy and the other 23 also a ventriculotomy. The ventriculotomy always consisted of a transverse incision a short distance below the pulmonary annulus. Of these children 93 had a perimembranous VSD and the other 7 a pure muscular defect. The ECG results of the 93 children with perimembranous VSDs were statistically analysed. The incidence of postoperative complete RBBB (CRBBB) in the ventriculotomy group was not higher than in the atriotimy group. Infants operated in the first half year of life were more prone to the development of CRBBB than the older children, probably because the VSDs were relatively larger in the younger than the older children. The risk of postoperative CRBBB was less in the children who had direct suture closure of the VSD compared with those who needed a Dacron patch to close the defect. The data in the literature generally indicate a higher incidence of CRBBB after a ventriculotomy than an atriotomy. The absence of this difference and the lower incidence of CRBBB after a ventriculotomy in our series compared with those of several other authors are suggested to be due to the type of ventriculotomy.

Intra-uterine tachycardia associated with multicystic encephalomalacia (MCE).

Multiple cystic brain lesions in neonates have been described as a result of a variety of causes. All events described thus far in association with multicystic encephalomalacia (MCE) seem to point to hypoxic-ischaemic injury as the common factor for this particular form of central nervous system damage. We describe a neonate in whom repeated, prolonged episodes of intrauterine tachycardia had been documented. Congestive heart failure and fetal hydrops were present at birth and MCE at the age of 13 wk. The obvious relationship between this child's intrauterine tachycardia and his MCE points to the fact that any fetus with prolonged tachycardia should be considered at risk of severe brain damage.

Actinobacillus actinomycetem-comitans endocarditis in a child with a prosthetic heart valve.

The first case of Actinobacillus actinomycetem-comitans endocarditis in a child with a prosthetic cardiac valve is reported. Endocarditis was possibly caused by dental work done without antibiotic prophylaxis four weeks prior to admission.

Subcostal two-dimensional echocardiographic recognition of a criss-cross heart with discordant ventriculo-arterial connection.

Two-dimensional echocardiography was performed on a patient with criss-cross atrioventricular (AV) relationship and ventriculo-arterial discordance. A systematic approach from the subcostal area revealed the complex cardiac pathology including the criss-cross AV relationship of right and left heart, indicating that this very abnormal relationship can be identified echocardiographically. The echocardiographic findings were confirmed by angiocardiography. Post-mortem investigation showed that much of the complexity, including the criss-cross AV relationship, had been caused by a secondary leftward torsion of the entire ventricular part of the heart.

The concurrence of dimensional aortic arch anomalies and abnormal left ventricular muscle bundles.

This anatomical study was designed to evaluate the concept that reduced blood flow through the embryonic preductal aorta contributes to the pathogenesis of dimensional aortic arch anomalies. For that purpose the intracardiac anatomy of 151 specimens was examined, of which 22 had an interruption, five atresia, 76 tubular hypoplasia, and 48 local coarctation of the aortic arch. Associated malformations were found in 148 specimens (98%); the remaining three (2%) had isolated local coarctation. Anomalies predisposing to reduced aortic blood flow were present in 128 specimens (85%). Among the potential obstructive factors affecting early morphogenesis, three left ventricular muscular structures seem to be particularly important: (1) the anterolateral muscle bundle, (2) the posteromedial muscle, and (3) leftward deviation of the anterior part of the ventricular septum. Obstructing combinations with these types of anomaly were identified in 77 cases (51%). The embryologic aspects of these muscular structures are discussed.

Histology of the persistent ductus arteriosus in cases of congenital rubella.

Histologic study of the persistent ductus arteriosus in case of a congenital rubella syndrome revealed that this persistency is probably due to an arrest in the development of the ductus. Histologically, it resembles a very immature ductus and not the most common type of persistent ductus arteriosus. The earlier finding, that in the human ductus arteriosus, the presence of an extensive subendothelial elastic lamina is incompatible with anatomic sealing, still holds.

Classification of ventricular septal defects.

A classification with clinical significance is proposed for ventricular septal defect based on the study of 220 hearts with defects of the ventricular septum. All had atrioventricular and ventriculoarterial concordance with normal relations of cardiac structure. For the purpose of classification, the ventricular septum was considered as possessing muscular and membranous portions, the muscular septum itself being divided into inlet, trabecular, and outlet (or infundibular) components. Defects were observed in the area of the membranous septum, termed perimembranous defects; within the muscular septum, termed muscular defects; or in the area of septum subjacent to the arterial valves, termed subarterial infundibular defects. Perimembranous defects were found extending either into the inlet, trabecular, or infundibular septa. Muscular defects were found in or between the inlet septum, trabecular septum, or infundibular septum. Review of the angiograms showed that the classification was easy to use in the catheterisation laboratory, and our observations suggest that the precision thus obtained has considerable surgical significance.

The ductus arteriosus in the preterm infant: histologic and clinical observations.

In order to elucidate some of the unexplained phenomena in prolonged patency of the ductus arteriosus in preterm infants, the histology of the ductus was studied in 27 cases. Some of the infants had been treated with indomethacin. Four morphologic maturation stages are distinguished. There was no strict relation between gestational age or birth weight and histologic maturation. Therefore, one cannot predict whether a ductus is likely to be mature at the time of birth. In all infants with clinically diagnosed prolonged patency of the ductus beyond the first week, the immature maturation stage or the permanent patent type was observed. In both stages, reopening after initial closure with indomethacin occurred.

Muscular ventricular septal defects: a reappraisal of the anatomy.

Among 79 autopsy specimens of heart with an isolated ventricular septal defect, there were 29 cases of muscular defect. Among 60 hearts with complete transposition of the great arteries and a ventricular septal defect, there were 13 cases with a muscular defect. All muscular defects could be classified in three different types, based on the specific pathologic anatomy of the ventricular septum. The central and posterior defects were usually large and single, the marginal defects were frequently small and multiple. In hearts with transposition, central muscular defects were extremely rare, whereas these defects were by far the most frequent muscular defects in isolated ventricular septal defect. Alternatively, the posterior type was more common in cases of transposition. Marginal muscular defects were rare in both groups of malformations.

[Effects of prostaglandin in heart abnormalities with needed patency of the arterial canal (clinical and histological study)]. / Effets de la prostaglandine dans les malformations cardiaques avec canal artériel obligatoire. Etude clinique et histologique.

Eight infants with cardiac malformations that were dependent on the patency of the ductus, were treated with Prostaglandin E 1 to reverse the closure of the duct. There was clinical improvement in 7 out of the 8 infants, confirmed by improvement in oxygen saturation and/or blood gases. In four cases the opening of the duct was visualised by angiography immediately after the prostaglandin infusion. Side-effects observed were transient pyrexia, flush reactions, apnoeic spells and one case of renal shock. Microscopic examination revealed in the four cases studied conspicuous edema of the media of the dictus. Because of the edema, the ductal wall is friable which indirectly may account for the severe lesions observed in the ductal wall. Prostaglandine E1 has a place in paediatric cardiology but in view of the observations made on the ductal wall it seems advisable to administer the drug only in a low dose and for a short duration.

Transposition of the great arteries with ventricular septal defect and pulmonary stenosis.

A postmortem investigation was carried out of 19 heart specimens with transposition of the great arteries, ventricular septal defect, and congenital subvalvular pulmonary stenosis. Certain types of obstruction appeared to be closely related to other features of the hearts. In cases with malalignment of the infundibular septum, the obstruction was caused by this septum and the anterolateral muscle bundle of the left ventricle. If the infundibular septum was deviated considerably to the left, the pulmonary stenosis was usually severe because the infundibular septum and anterolateral muscle bundle were joined. This junction resulted in a relatively posterior position of the pulmonary orifice in the left ventricle. A less extreme deviation of the infundibular septum resulted in an obstruction by this septum and by the anterolateral muscle bundle, situated at the right and the left sides of the pulmonary orifice respectively. In some cases of paratricuspid ventricular septal defect an anomalously attached and cleft anterior leaflet of the mitral valve was found. This, together with a leftward deviation of the anterior left ventricular part of the ventricular septum, caused the obstruction.

Ventricular septal defect associated with left ventricular outlfow tract obstruction below the defect.

Muscular subaortic stenosis associated with ventricular septal defect (VSD) is a rare but important anomaly. Two types of left ventricular outflow tract (LVOT) obstruction should be distinguished on the basis of morphologic as well as hemodynamic differences, depending on whether the stenosis is localized above (Type I) or below (Type II) the defect. The five cases presented are all in the latter category. In the first two cases the correct diagnosis was not made until after repair of the VSD. Two patients had previously undergone banding of the pulmonary artery (PAB). Marked carotid shudder and a vertical QRS axis in the frontal plane were presented in all cases. For the diagnosis to be established by catheterization, the catheter tip must be maneuvered into the apical part of the left ventricular cavity in order to detect the stenosis on the withdrawal curve. It is difficult to visualize the stenosis by angiography. The surgical approach through the VSD via a right atriotomy is highly recommended for Type II subaortic stenosis.

Histopathology of the ductus arteriosus after prostaglandin E1 administration in ductus dependent cardiac anomalies.

The histology of the ductus arteriosus was studied after prostaglandin E1 (PGE1) administration in 4 infants with ductus dependent cardiac malformations. Pronounced pathological changes were found in each instance. The changes consisted of oedema of the media with separation of medial components by clear spaces, pathological interruptions of the internal elastic lamina, and intimal lacerations, some of which extended into the media. The findings suggest that PGE1 administration has a profound weakening effect on the structure of the wall of the ductus arteriosus, rendering the vessel prone to laceration.

Effect of E1 type prostaglandin on hypoxemia in a cyanotic congenital cardiac malformation.

Prostaglandin type E1 has been administered on 4 different occasions in a newborn with a ductus-dependent complex congenital cyanotic heart disease. Dramatic improvement of the arterial oxygen concentration followed each prostaglandin infusion. Increased pulmonary circulation and widening of the ductus arteriosus were seen on angiographic examination. Transient flushing of the skin and mild pyrexia were the only complications noted. It is advised that prostaglandin type E1 be used in ductus-dependent heart diseases as an emergency therapy when indicated.