Transient foramen ovale incompetence in the normal newborn: an echocardiographic study.

UNLABELLED: To assess presence, predominant direction and natural history of interatrial shunt flow in the normal newborn period an uncontrolled pilot study was performed. Twenty term ( > 36 completed weeks gestational age) newborns were studied using cross sectional, M-mode and colour Doppler echocardiography; cardiac, pulmonary or renal disease were excluded before entry to the study. In 11 of 20 normal term newborns a predominant left to right interatrial shunt was detected on the 1st day after birth. This shunting, taking place in ventricular systole, disappeared in 10 cases during the first 6 postnatal days and in 1 case after 6 weeks. No relation was found between the presence of an atrial left to right shunt and gestational age or patency of the ductus arteriosus. CONCLUSION: We conclude that interatrial left to right shunting is common in half of the normal newborns (95% confidence interval 31.5%-76.9%), during the first 6 days of extra-uterine life. Our findings may be explained by a transient period of physiological expansion of extracellular volume in the newborn, resulting in slight atrial stretch, and this in combination with a relatively short foramen ovale flap.

Ventricular septal defect with overriding aorta in trisomy-18.

In a child with trisomy-18 prenatal echocardiography demonstrated the presence of a ventricular septal defect with overriding aorta. In a previous anatomical study of 18 hearts with this malformation we found a 50% concurrence rate with trisomy-18. In case of prenatal echocardiographic detection of a ventricular septal defect with overriding aorta, we advise thorough ultrasound examination for additional malformations as seen in trisomy-18; subsequently this procedure should be completed by cytogenetic analysis of amniotic cells.

Anatomic characteristics of ventricular septal defect associated with coarctation of the aorta.

The morphologic characteristics of ventricular septal defect (VSD) and left ventricular outflow tract were studied in 45 hearts with VSD and coarctation of the aorta (C of A). Forty-one VSDs were classified into 1 of 4 categories. The first category includes 19 central muscular VSDs (43%), among which 3 hearts had the architecture of a spontaneously closed defect. The second category includes 10 perimembranous inlet defects (23%) with overlying tricuspid valve. The third category is formed by 8 perimembranous VSDs with leftward outlet septal malalignment (18%) and the fourth category includes 4 subarterial VSDs (8%) in which leftward malalignment of a deficient outlet septum results in subpulmonary localization of the defect. In addition to the main categories, 1 membranous, 1 perimembranous trabecular, 1 apical muscular and 1 doubly committed subarterial defects were identified. The left ventricular outflow tract was assessed as normal in only 2 cases. In 43 cases the left ventricular outflow tract was compromised by 1 or more of the following anomalies: anterolateral muscle bundle, anteroseptal twist, bicuspid aortic valve or a leftward malaligned outlet septum. These findings support the hypothesis of C of A being hemodynamically induced by anomalies of the left ventricular outflow tract. Previous studies have established that muscular, membranous and perimembranous inlet defects are prone to close spontaneously, in contrast to malalignment and subarterial VSDs. The present study shows that 70% of the VSDs belong to types characterized by a high incidence of spontaneous closure.

Unclassified familial cardiomyopathy with ventricular dysrhythmia.

The case is described of a boy with some right ventricular dysplasia and episodes of ventricular tachycardia of left bundle branch block pattern who had symptoms from the age of 1 month. Angiography and cardiac biopsy demonstrated major involvement of the left ventricular myocardium. A sister of the patient presented at the age of 2 months with predominantly left ventricular cardiomyopathy; clinical signs and angiography suggested the presence of right ventricular dysplasia as well. She died suddenly at the age of 9 years. Her brother, now aged 14 years, is being treated with antiarrhythmic drugs. The hypothesis of this cardiomyopathy being a variant of "arrhythmogenic right ventricular dysplasia syndrome" is discussed.

Ventricular septal defect with normally connected and with transposed great arteries.

The morphologic characteristics of 50 hearts with ventricular septal defect (VSD) and ventriculoarterial (VA) discordance were compared with those of 105 hearts with VSD and VA concordance. Of the 7 VSD types in VA concordant hearts, the 3 that occur most frequently--central muscular (26%), perimembranous with leftward malalignment of the outlet septum (18%) and perimembranous with overriding posterior artery (15%)--were absent in VA discordant hearts. Of the 6 with VA discordance, 2 principal VSD types (perimembranous with rightward outlet septum malalignment [25%] and muscular infundibular with leftward outlet septum malalignment [15%]) did not occur in VA concordant specimens. Thus, 4 VSD types occurred with VA concordance as well as with VA discordance: subarterial (12% concordance, 3% discordance); perimembranous inlet (15%, 27%); muscular inlet (10%, 27%); and membranous (4%, 3%). Of these 4 common groups, perimembranous inlet VSD with VA concordance was accompanied by tricuspid valve anomalies; however, mitral valve anomalies complicated this type of VSD with VA discordance. It is concluded that in hearts with VA concordance vs hearts with VA discordance the spectrum of VSD and ventricular morphology is different.

Abnormal architecture of the ventricles in hearts with an overriding aortic valve and a perimembranous ventricular septal defect ("Eisenmenger VSD").

Among 111 hearts with so-called "isolated" ventricular septal defect, 18 specimens were found to have a subaortic perimembranous defect with an overriding aortic valve but without pulmonary stenosis. The ventricular architecture was characterized by several abnormalities. A constant finding was the wide right ventricular outflow tract. The outlet septum had its normal continuity with the septomarginal trabecula, but its parietal extension was located relatively far anteriorly. Part of the aortic valve thus inserted to the right ventricular component of the ventriculo-infundibular fold in the gap between the outlet septum and the tricuspid valve. Left ventricular abnormalities comprised mitral valve anomalies in all cases. There was an anteroseptal twist (leftward thickening of the anterior part of the ventricular septum) in 16 cases. A bicuspid aortic valve and/or malformed cusps were observed in 4 cases. Because of the linking phenomenon of aortic override, we also examined 10 hearts with tetralogy of Fallot and, in the latter, such abnormalities were not found. Our observations indicate that this seemingly simple type of defect is part of a complex malformation involving both septation and valve formation. Awareness of the existence of the architectural abnormalities might make them accessible for echocardiographic diagnosis. It was noteworthy that 11 of the 18 patients had chromosomal abnormalities, 9 of them presenting with trisomy-18.

Morphology of ventricular septal defect in complete transposition of the great arteries.

The morphologic characteristics of ventricular septal defect (VSD) was studied in 50 hearts with complete transposition of the great arteries. Except for 1 membranous and 1 subarterial defect, all VSDs could be classified into 1 of 4 categories. Group A included 14 specimens with a perimembranous defect extending into inlet and trabecular septum with rightward malalignment of the outlet septum; in this group aortic arch anomalies (6 hearts) and tricuspid valve abnormalities (7 hearts) were frequently present. Group B comprised 13 hearts with perimembranous defects extending into the inlet septum; 11 hearts in this group also had an anomalous mitral valve. Group C included 13 hearts with muscular inlet defects, with signs of spontaneous closure by marginal fibrosis in 10 cases. Group D included 8 hearts with muscular infundibular defects; in 6 of these hearts the outlet septum was malaligned to the left, causing different degrees of subpulmonary stenosis. A small second VSD was present in 5 hearts. Thus, the spectrum of VSD in transposition of the great arteries is different from that of isolated VSD.

Transposition of the great arteries and narrowing of the aortic arch. Emphasis on right ventricular characteristics.

Of 279 patients with transposition of the great arteries, 14(5%) had narrowing of the aorta, including local coarctation (6), isthmus hypoplasia (6), isthmus atresia (1), and kinking of the aorta (1). There were six deaths in 10 surgically treated patients; in addition four patients died before operation. Two of the four survivors had a subpulmonary malalignment ventricular septal defect with angiocardiographic narrowing of the right ventricular outflow tract, two had evidence of redundant muscle tissue obstructing the right ventricular outflow tract. Necropsy showed the presence of anatomical right ventricular outflow tract or inflow tract obstruction or both in all 10 cases. Outflow tract obstruction was represented by anterior displacement of the infundibular septum and ventriculoinfundibular fold (in hearts with a subpulmonary malalignment ventricular septal defect) or by redundant muscle tissue; inflow tract obstruction was represented by hypoplasia of the tricuspid valve. It is concluded that the combination of transposition of the great arteries and narrowing of the aorta is always accompanied by right ventricular outflow or inflow tract obstruction or both; the right ventricular abnormalities are probably responsible for the presence of the aortic arch anomalies by reducing aortic flow during morphogenesis. Successful surgical treatment of this complex anomaly is feasible in selected cases.

Anatomic obstruction of the right ventricular outflow tract in transposition of the great arteries.

In 126 hearts with transposition of the great arteries (TGA), morphologic features of the right ventricular (RV) outflow tract were analyzed. Distinct anatomic outflow tract obstruction was found in 15 of the 55 hearts with a ventricular septal defect (VSD) (27%): 12 had a perimembranous defect (predominantly extending into the infundibulum), 2 had an inlet, and 1 had an infundibular defect. In 12 hearts, outflow tract obstruction was caused by anterior displacement of infundibular septum and ventriculoinfundibular fold; in 3 hearts, it was caused by bulging of the trabecula septomarginalis or ventriculoinfundibular fold, or both. Of 71 hearts with an intact ventricular septum, only 2 (3%) had RV outflow tract obstruction: 1 had a trabecula in front of the aortic ostium and in the other an aberrant hypertrophic muscle bundle crossed the RV cavity, obstructing the entrance to the infundibulum. Associated malformations included aortic arch malformations (6 cases) and tricuspid valve anomalies (6 cases). Thus, anatomic RV outflow tract obstruction may constitute a complicating factor in TGA, notably in cases with VSD. A systemic RV blood pressure may trigger hypertrophy, resulting in progression of the obstruction; establishing normal RV pressure by a "switch" procedure might prevent this progression.

Congenital mitral valve anomalies in transposition of the great arteries.

In 165 hearts in transposition of the great arteries, including 16 with a ventricular septal defect and overriding pulmonary trunk and 5 with a so-called posterior transposition, the left ventricle was studied with emphasis on the morphology of the mitral valve. Distinct mitral valve anomalies were found in 36 cases (22 percent), and four categories of anomalies could be identified. Group A included 16 specimens with a cleft anterior mitral valve leaflet. The cleft was complete or partial. Partial clefts continued as a fibrous cord within the leaflet. In eight cases the cleft was situated posterior or lateral to the pulmonary ostium; in these cases the left ventricular outflow tract was not narrowed. Severe outflow tract stenosis was present in another eight cases in which the cleft was located anterior to the pulmonary ostium, usually in combination with a ventricular septal defect, and in four of these specimens there was straddling of the mitral valve. Group B included eight hearts with an abnormal size or position of the mitral valve, or both, the valve being hypoplastic or rotated clockwise, or both. Group C comprised seven hearts showing redundant left ventricular structures involving the mitral valve, among which were anomalous tissue strands, subpulmonary rings and redundant valve tissue. Group D included five specimens with deficient papillary muscles. It is concluded that an abnormal mitral valve is not unusual in hearts with transposition of the great arteries. The findings are notably important for those patients for whom anatomic surgical correction of the transposition is considered. In comparison with the venous baffle procedure, this operation makes greater demands on the structure of the mitral valve because the pressure in the left ventricle remains at systemic level. Thorough investigation of mitral valve anatomy and function is necessary before anatomic correction is considered.

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.

Relation between aortic arch hypoplasia of variable severity and central muscular ventricular septal defects: emphasis on associated left ventricular abnormalities.

Among 25 heart specimens with a central muscular ventricular septal defect (including 3 with the architecture of a spontaneously closed defect), only 6 (24 percent) had an aortic arch of normal size and configuration. Isthmus atresia was present in one case, isthmus hypoplasia in eight cases, local coarctation in six and a combination of isthmus hypoplasia and local coarctation in another four. A study of the left ventricular morphologic features of the 25 hearts revealed the presence of a spectrum of additional anomalies. The aortic valve was bicuspid in 16 and mitral valve anomalies were present in 13 specimens. Mitral valve deformities present in the 13 specimens included congenital stenosis (5), deficient chordae tendineae (4), parachute valve (2), adherent valve leaflets (1) and a hypoplastic posteromedial papillary muscle (1). Furthermore, there was a large incidence of abnormal left ventricular muscular structures that could be classified into three basic types: (1) the anteroseptal "twist": thickening and deviation of the anterobasal septum and anterior wall, resulting in a relatively posterior position of the aortic ostium (16 cases); (2) a prominent anterolateral muscle (9 cases); and (3) a posteromedial muscle (9 cases). It is concluded that a central muscular ventricular septal defect is not an isolated malformation but is commonly part of a complex developmental anomaly. This complex of associated inflow and outflow tract lesions presumably may cause reduced aortic flow during morphogenesis, resulting in aortic arch hypoplasia of various degrees of severity.

Continuous stroke volume and cardiac output from intra-ventricular dimensions obtained with impedance catheter.

To improve assessment of ventricular function during cardiac catheterisation there should be available a continuous registration of stroke volume and cardiac output in addition to ventricular pressure. To obtain the desired volumetric quantities a catheter has been developed which measures changes in intraventricular dimensions by electrical impedance. For this purpose, the catheter is equipped with eight electrodes spaced over a distance equal to the long axis of the left ventricle into which it is introduced. A constant current is imposed between the outermost electrodes while the inner six are used to measure resistance of volume segments of the blood contained within the ventricular cavity. The difference in resistance at the beginning and end of ejection is proportional to the contribution of each segment to stroke volume, which follows from addition to the segmental terms. Calibration is obtained by measuring electrical conductivity of a blood sample. The catheter was tested over a tenfold range of cardiac output, both in vitro, using an artificial heart model, while performance in vivo was evaluated in 12 dogs. In the animals study, stroke volume and cardiac output from the catheter were compared with flows obtained with an electromagnetic flowmeter. In both studies, linear regression analysis showed excellent correlation of cardiac output (r = 0.99, n = 10 in vitro, r = 0.95, n = 126 in vivo) while the regression equations were close to those of identity. Very good correlation (r = 0.98, n = 28) was also obtained for stroke volumes on a beat to beat basis during arrhythmia. It is concluded that the catheter, which has great potential for application in man, fulfills its primary aim of continuously recording stroke volume and cardiac output.

Echocardiographic diagnosis of an aneurysm of the membranous ventricular septum.

A patient with a small ventricular septal defect complicated by an aneurysm of the membranous ventricular septum is reported. The aneurysm was diagnosed by left ventricular angiocardiography and, non-invasively, by echocardiography. The clinical significance of the anomaly is discussed in relation to the pertinent literature.

Ventricular rhythm obscuring the diagnosis of ostium primum atrial septum defect.

A 13 year old boy with an ostium primum atrial septal defect associated with alternating periods of sinus rhythm and ventricular rhythm is presented. Absence of auscultatory and phonocardiographic signs of an atrial septal defect made it impossible to diagnose the defect correctly during periods of ventricular rhythm.

Value of systolic time intervals in assessing severity of congenital aortic stenosis in children.

Simultaneous recordings have been made of electrocardiogram, phonocardiogram, carotid pulse tracing, left ventricular pressure, and aortic pressure in 27 children with aortic valve stenosis and 3 children with membranous subaortic stenosis. Peak systolic pressure difference ranged from 10 to 110 mmHg (1.3 to 14.6 kPa). None of the patients had congestive heart failure and cardiac output was in the normal range in all. Total electromechanical systole, left ventricular ejection time, and pre-ejection time were corrected for heart rate, age, and sex. Mild stenosis (peak systolic pressure difference less than or equal to 50 mmHg (6.7 kPa)) was present in 18, severe stenosis (peak systolic pressure difference greater than 50 mmHg) in 12 patients. The externally measured pre-ejection time and ejection time proved to be nearly equal to the corresponding intervals measured internally; from these data it is concluded that pre-ejection time and ejection time in children with aortic stenosis can be measured reliably by non-invasive methods. Mean values for corrected total electromechanical systole and ejection time were prolonged, but the corrected pre-ejection time did not differ from the normal value. When corrected time intervals were plotted against severity of the aortic stenosis as expressed by the peak systolic pressure difference or the aortic valve orifice index, a wide scatter was found. It is concluded that a normal ejection time is strong evidence against a peak systolic pressure difference of more than 50 mmHg (6.7 kPa) or an aortic valve orifice index less than 0.70 cm2 per m2 BSA. A prolonged ejection time, however, may occur in mild as well as in severe stenosis. Total electromechanical systole and pre-ejection time have no value in predicting the severity of aortic stenosis in children.