Tetralogy of Fallot with congenital aortic valvar stenosis: the tetralogy-truncus interrelationship

Two rare patients are reported with tetralogy of Fallot and congenital aortic valvar stenosis. The anatomic and developmental interrelationship between tetralogy of Fallot and truncus arteriosus is summarized. A study of 100 randomly selected postmortem cases of tetralogy revealed aortic valve pathology in 8%, myxomatous aortic valve leaflets without stenosis in 4%, bicuspid aortic valves without stenosis in 3%, and congenital aortic valvar stenosis in 1%. The frequency of systemic semilunar valve pathology in truncus was much higher (66%): moderate to marked myxomatous change in 44%, mild myxomatous change in 22%, truncal valvar stenosis in 11%, and truncal valvar regurgitation in 15%. Being aware of the tetralogy-truncus interrelationship and knowing that myxomatous aortic valves are prone to premature calcific aortic stenosis and/or regurgitation, physicians should follow the aortic valves of surgically repaired patients with tetralogy of Fallot and truncus arteriosus long term with great care. Timely aortic valvuloplasty or replacement may well prove life-saving in such patients.

Isolated left-sided scimitar vein connecting all left pulmonary veins to the right inferior vena cava

When the common pulmonary vein fails to develop, the embryonic connections of the pulmonary veins to one or more of the systemic veins almost always persist. Anomalous pulmonary venous connections to the inferior vena cava (IVC) are typically characterized by hypoplasia of the involved pulmonary veins and pulmonary artery, as well as abnormal parenchyma of the involved lung. Such cases have been described as "scimitar syndrome." We report the case of a young female patient in whom all the left pulmonary veins converged into a common vessel that drained into the IVC but who had a normal left pulmonary artery and left lung. Surgical intervention was successful, and our patient is still alive.

Superoinferior ventricles with superior left ventricle and inferior right ventricle: a newly recognized form of congenital heart disease

We report the first known case of supero-inferior ventricles with a superior morphologically left ventricle and an inferior morphologically right ventricle. This 2 1/2-year-old boy also had dextrocardia, double-outlet right ventricle [S,L,L], right-sided mitral atresia, left-sided tricuspid regurgitation, a large conoventricular type of ventricular septal defect, and pulmonary outflow tract stenosis. This very rare form of superoinferior ventricles appears to be due to excessive levorotation (approximately equal to 170 degrees) of discordant L-loop ventricles.

Biatrial or left atrial drainage of the right superior vena cava: anatomic, morphogenetic, and surgical considerations--report of three new cases and literature review

Since the posterior wall of the right superior vena cava (RSVC) is contiguous with the anterior wall of the right upper pulmonary veins, a localized defect in this common wall may create a cavopulmonary venous confluence without eliminating the normal connection of the same right pulmonary veins with the left atrium (LA). Through this defect, blood of the unroofed right pulmonary veins will drain into the RSVC and right atrium (RA), and blood from the RSVC may shunt into the right pulmonary veins and LA. Hemodynamically, the RSVC will become biatrial. If the RSVC blood flows preferentially into the LA, its right atrial orifice will become stenotic or even atretic. If atretic, the normally positioned RSVC will drain entirely into the LA. In this report, we present the clinical and anatomical findings of two postmortem cases with biatrial drainage of the RSVC. We also document the clinical, echocardiographic, angiocardiographic, and surgical data of a living patient with left atrial drainage of the RSVC and tetralogy of Fallot with pulmonary atresia. The relevant literature and surgical treatment are reviewed, and the morphogenesis of the biatrial and left atrial RSVC is considered.

Single origin of right and left pulmonary artery branches from ascending aorta with nonbranching main pulmonary artery: relevance to a new understanding of truncus arteriosus

We report the third known case of origin of the right and left pulmonary artery branches from the ascending aorta via a short common pulmonary artery. A large unbranching main pulmonary artery opened through a patent ductus arteriosus into the descending thoracic aorta. Preductal coarctation of the aorta and multiple congenital anomalies were also present. This rare cardiovascular malformation facilitates a new anatomic and developmental understanding of truncus arteriosus.

Healing response to the Clamshell device for closure of intracardiac defects in humans

The healing response to intracardiac devices in humans is largely unknown. During regulatory trials using the Clamshell device in over 800 patients, attempts were made to perform histopathological evaluation of all explanted devices. We reviewed all those with complete histopathological examination (n = 12) from Fontan baffles (n = 4), ventricular septal defects (n = 2), and atrial septal defects (ASD; n = 6), explanted at 2.7 months to 3.6 years (median, 1.6 years), at autopsy (n = 1) or surgery (n = 11), performed for residual defects (n = 5), atrial masses (n = 3), or Fontan revision (n = 3). All but one were nearly (n = 3) or completely (n = 8) covered by pseudointima, composed of fibroelastic tissue, predominantly collagen, with focal foreign body reaction in contact with fabric, without acute inflammation or infection. Atrial masses of granulation tissue were present in three cases (ASD), opposite to protruding fractured arms. No associations were identified between coverage and closure status, position, arm fractures, or implant period. In conclusion, the healing response to transcatheter Clamshell implantation in humans is characterized by a relatively rapid development of a nonthrombotic pseudointima composed of fibroelastic tissue with minimal foreign body reaction. Cathet Cardiovasc Intervent 2001;54:101-111.

Three-dimensional echocardiography of the atrial septum

This article details the important contribution of three-dimensional echocardiography for catheterization device closure of secundum atrial septal defects. Aspects presented include three-dimensional echocardiographic application in preselection of patients and in selection of the type and size of the atrial septal occluder devices. Unique three-dimensional echocardiographic imaging planes are shown that depict the size and shape of the defect, the important rim tissue surrounding the defect, and the images that demonstrate successful device placement. Details of the acquisition phase, digital reformatting, and the eventual rendering of standard three-dimensional echocardiographic imaging planes of the atrial septum are shown. Three-dimensional echocardiography not only provides important additional information, but also enhances understanding of standard two-dimensional studies.

Congenital left ventricular aneurysm: clinical, imaging, pathologic, and surgical findings in seven new cases

BACKGROUND

Congenital left ventricular aneurysm is a poorly understood and potentially lethal entity. Methods and Results In a clinicopathologic study of 7 new cases, the major presenting features in 6 patients were congestive heart failure in 4, ventricular arrhythmias in a 32-week fetus, and multiple congenital anomalies in a fetus with trisomy 13. Accurate diagnosis was achieved in all 3 living patients by echocardiography, angiocardiography, and magnetic resonance imaging. The aneurysm was predominantly apical in 3 and involved most of the left ventricular free wall in 4. Of the 3 living patients, medical management alone sufficed in 2. The third, a newborn boy, underwent a new and successful aneurysm-exclusion left ventriculoplasty. The mitral valve was abnormal in all 4 autopsied cases, the papillary muscles being short, thin, or absent. The aneurysm was thinner and its area was larger than that of the nonaneurysmal left ventricle in all necropsied patients.

CONCLUSIONS

Congenital left ventricular aneurysm appears to be a developmental anomaly, an idiopathic dysplasia of left ventricular endocardium and myocardium. No evidence of a viral etiology was found. Some neonates can be managed medically, but others require urgent surgical intervention. A new surgical operation is presented, a functional left ventricular aneurysmectomy that minimizes intraoperative and postoperative blood loss and that preserves the coronary arteries.

Absent pulmonary valve with tricuspid atresia or severe tricuspid stenosis: report of three cases and review of the literature

Absence of the pulmonary valve occurs usually in association with tetralogy of Fallot and occasionally with an atrial septal defect or as an isolated lesion. Very rarely it occurs with tricuspid atresia, intact ventricular septum, and dysplasia of the right ventricular free wall and of the ventricular septum. We present the clinical, anatomic, and histologic findings of a new case, and for the first time, the data from two patients with absent pulmonary valve and severe tricuspid stenosis, who exhibited similar histologic findings. We also reviewed the clinical and anatomic data of 24 previously published cases and compared them with the new cases. In all three new cases, the myocardium of the right ventricle was very abnormal. In the two cases with tricuspid stenosis, large segments of myocardium were replaced with sinusoids and fibrous tissue. In the case with tricuspid atresia, the right ventricular free wall contained only fibroelastic tissue. The ventricular septum in all three patients showed asymmetric hypertrophy and in two of the three patients, multiple sinusoids had replaced large segments of myocardial cells. The left ventricular free wall myocardium and the walls of the great arteries were unremarkable. Our data indicate that myocardial depletion involving the right ventricular free wall and the ventricular septum and its replacement by sinusoids and fibroelastic tissue occur not only in cases of absent pulmonary valve with tricuspid atresia but also in cases of absent pulmonary valve with tricuspid stenosis. The degree of myocardial depletion varies and is more severe when the tricuspid valve is atretic.

Extracardiac anomalies in the heterotaxy syndromes with focus on anomalies of midline-associated structures

The extracardiac defects in patients with heterotaxy have not been examined as extensively as cardiac defects. We found a high incidence of midline-associated defects in 160 autopsied cases of heterotaxy (asplenia, polysplenia, or single right-sided spleen). Fifty-two percent of patients with left-sided polysplenia had a midline-associated defect, as did 45% of those with asplenia. Most common were musculoskeletal or genitourinary anomalies, as well as cleft palate. Fused adrenal glands and anal stenosis or atresia occurred exclusively among patients with asplenia. A midline anomaly was twice as likely to be detected on complete autopsy than from clinical findings alone. Linkage studies should take into account that affected subjects may have isolated subclinical midline defects. The high incidence of midline-associated defects supports the theory that the midline plays a critical role in establishing left-right asymmetry in the body. Comparison of these defects with mouse models of laterality defects suggests that mutations that disrupt the transforming growth factor beta pathway may result in heterotaxy.

Acute animal studies of the STARFlex system: a new self-centering cardioSEAL septal occluder

The STARFlex system is a modified CardioSEAL device with a flexible self-centering mechanism comprised of nitinol springs strung between opposing arms, a connecting ball (sleeve joint that allows the device to pivot prerelease), and a front-loading delivery system. It was designed to allow a smaller device/defect sizing ratio and delivery profile, provide centering capability, and improve closure rates. To test this system, 13 devices (23, 28, and 33 mm) were deployed in six sheep within created atrial septal defects (12- to 22-mm diameter; n = 10), in the left atrium (n = 2), and in inferior vena cava (n = 1). All implantations in atrial septal defects were successful, with device/defect ratio ranging from 1.3 to 1.9 (median, 1.3), with no residual leak by angiography or echocardiography in seven (3/10 had </= small immediate leaks). The STARFlex system was effective in closing created atrial septal defects using a 10 Fr delivery sheath and low device/defect sizing ratios, comparing favorably with the standard CardioSEAL. Cathet. Cardiovasc. Intervent. 49:225-233, 2000.

Surgical closure of apical ventricular septal defects through a right ventricular apical infundibulotomy

BACKGROUND

We present a new understanding of the anatomic position of apical ventricular septal defects and its surgical relevance. These defects occur between the left ventricular apex and the infundibular apex, rather than between the left and right ventricular apices. Often a sizable apical recess, the infundibular apex lies anteriorly and inferiorly to the moderator band and is the most leftward part of the right ventricle.

METHODS

Four patients (2 boys and 2 girls) with a mean age of 109 days (range, 48 to 217 days) underwent patch closure through an apical infundibulotomy, which allowed complete visualization of the muscular apical ventricular septal defect.

RESULTS

There were no early or late deaths at operation. No significant residual shunt at ventricular level was detected by postoperative two-dimensional and Doppler echocardiography. Intraoperative comparison of right atrial and pulmonary arterial blood samples showed a difference of less than 5%. At a mean follow-up of 18 months, all the patients are asymptomatic and growing well.

CONCLUSIONS

The successful outcome of these 4 patients indicates that surgical closure of apical ventricular septal defects can be achieved safely and completely in early infancy through a limited right ventricular apical infundibulotomy. Long-term follow-up of these and similar patients is needed to provide further evaluation of this approach.

Straddling tricuspid valve as a sign of ventriculoatrial malalignment: A morphometric study of 19 postmortem cases

BACKGROUND

Straddling tricuspid valve, despite extensive investigation, remains an incompletely understood form of complex congenital heart disease.

METHODS

A morphometric study of 19 postmortem cases of straddling tricuspid valve was performed, and the results were compared with 32 normal control heart specimens.

RESULTS

In straddling tricuspid valve, marked malalignment of the ventricles was always found relative to the atria. The angle between the ventricular septum and the atrial septum in the short-axis projection averaged 61 degrees +/- 24 degrees, the normal ventriculoatrial septal angle averaging 5 degrees +/- 2 degrees (P <. 001). The right ventricular sinus (inflow tract) was significantly smaller than the left (P <.01). A ventricular septal defect was present in 79%: atrioventricular canal type in 42%, atrioventricular canal type confluent with a conoventricular defect in 26%, and a conoventricular defect in 11%. When the straddling tricuspid valve adhered to the crest of the muscular ventricular septum (n = 4 cases, 21%), the 2 salient findings were (1) an intact ventricular septum and (2) double-outlet right atrium. The nonstraddling part of the tricuspid valve opened into the small right ventricle. The straddling part of the tricuspid valve opened into the larger left ventricle. The mitral valve also opened into the left ventricle. Hence hearts with double-outlet right atrium had 3 atrioventricular valves. Congenital mitral stenosis was present in 26% of this series.

CONCLUSION

Straddling tricuspid valve was always characterized by marked ventriculoatrial malalignment, indicated by an abnormally large ventriculoatrial septal angle, best seen in the short-axis projection.

The modified Fontan procedure: morphometry and surgical implications

BACKGROUND

The modified Fontan procedure for patients with only one well-formed ventricle is now widely regarded as palliative, not curative.

METHODS

To improve the surgical management and postoperative follow-up of such patients, a morphometric study of 33 postmortem cases was done.

RESULTS

The three main causes of death were congestive heart failure (82%), arrhythmias (12%), and central nervous system dysfunction (6%). The cross-sectional area of the Fontan anastomosis (FA) relative to the systemic venous area (SVA) and relative to the body surface area (BSA) revealed that the Fontan pathway was often obstructive. The mean FA/SVA index was 73% less than normal: 0.54 +/- 0.22, range 0.13 to 0.98. The mean FA/BSA index was 70% less than normal: 143.52 +/- 50.01 mm2/M2, range 55.09 to 261.67 mm2/M2.

CONCLUSIONS

The main surgical challenge is to minimize or eliminate prepulmonary stenosis. Although significant postoperative obstruction was often not evident hemodynamically because of small or absent gradients, the presence of important obstruction of the Fontan pathway was clearly revealed by morphometry.

Truncus arteriosus with anomalous pulmonary venous connection

The anatomic, diagnostic, and management findings of 6 patients with truncus arteriosus and anomalous pulmonary venous connections are described. Additional risk factors indicative of poor prognosis were found in 3 of 4 patients with truncus arteriosus and totally anomalous pulmonary venous connection and in 1 patient with partially anomalous pulmonary venous connection.

Mitral and aortic atresia associated with hypoplastic right lung, crossover segment of right lower lobe, and anomalous scimitar-like right pulmonary venous connection with inferior vena cava: clinical, angiocardiographic, and autopsy findings in a rare case

A newborn female infant was found to have a unique and previously unreported group of anomalies: (1) mitral and aortic atresia with a highly obstructive atrial septum; (2) hypoplasia of the right lung with a crossover segment involving the right lower lobe; (3) normally connected pulmonary veins, two from the left lung and one from the right; and (4) a large anomalous branch of the right pulmonary vein of scimitar configuration that anastomosed with the normally connected right pulmonary vein and with the inferior vena cava (IVC). The scimitar vein appeared obstructed at its junction with the right pulmonary vein and at its junction with the inferior vena cava within the hepatic parenchyma. To our knowledge, this is the first report of a scimitar-like vein coexisting with mitral and aortic atresia and connecting both with the right pulmonary vein and with the inferior vena cava. The highly obstructed left atrium was partially decompressed by retrograde blood flow via the normally connected right pulmonary vein to the anomalous scimitar venous pathway and thence to the inferior vena cava via a pulmonary-to-IVC collateral vein.

The large window ductus: a surgical trap

A rare window type of patent ductus arteriosus is reported that was large (15 mm in maximal transverse dimension) but had virtually no length and hence was externally invisible. The smaller aortic isthmus (4 mm in diameter), which was intrapericardial, was mistaken for the ductus and was inadvertently clip-occluded, leading to death. After a specific diagnosis is made, the large window ductus should be patched on cardiopulmonary bypass with a transpulmonary approach.

Pathologic anatomy of corrected transposition of the great arteries: medical and surgical implications

BACKGROUND

Because the double-switch operation (atrial switch plus arterial switch) has recently become feasible in selected patients with congenitally physiologically corrected transposition of the great arteries, a detailed understanding of the pathologic anatomy is now mandatory for cardiologists, radiologists, and surgeons.

METHODS

A detailed study of the pathologic anatomy, the clinical implications, and the surgical implications was undertaken on 33 postmortem cases with two ventricles. A companion study was also performed of 44 postmortem cases with functionally only one ventricle. Hence this was an investigation of 77 postmortem cases.

RESULTS

Three main anatomic types of corrected transposition of the great arteries (TGA) with two ventricles were found: (1) TGA with solitus atria (S), L-loop ventricles (L), and L-TGA (L), that is, TGA [S,L,L] in 31 cases (94%); (2) TGA with solitus atria (S), L-loop ventricles (L), and D-TGA (D), that is, TGA [S,L,D] in 1 case (3%); and (3) TGA with inverted atria (I), D-loop ventricles (D), and D-TGA (D), that is, TGA [I,D,D] in 1 case (3%). Associated malformations resulted in 13 anatomic subtypes. In classical corrected TGA [S,L,L] with two ventricles, anomalies of the left-sided systemic tricuspid valve were present in 97%, with malformations of the left-sided systemic right ventricle in 91%.

CONCLUSIONS

The findings in corrected TGA with two ventricles and in cases with single ventricle support the view that anatomic repair such as the double-switch procedure, or left-sided right ventricle bypass such as the modified Norwood procedure followed by the modified Fontan procedure, is indicated in selected patients.

Interrupted inferior vena cava in asplenia syndrome and a review of the hereditary patterns of visceral situs abnormalities

We present the clinical and postmortem findings of the first photographically documented case of asplenia and interrupted inferior vena cava and the anatomic findings of 5 previously reported cases. A brief review of the various hereditary patterns of visceral situs abnormalities suggests that, at least in some cases, the asplenia and polysplenia syndromes are etiologically and pathogenetically interrelated.

Causes of death after the modified Norwood procedure: a study of 122 postmortem cases

BACKGROUND

Although the results of the modified Norwood procedure as palliation for the hypoplastic left heart syndrome have improved considerably, in-hospital mortality remains high (28% to 46%).

METHODS

To establish the causes of death and consider their therapeutic applications, we reviewed our pathology experience from 1980 to 1995, inclusive, regarding 122 patients who died after undergoing the Norwood procedure.

RESULTS

The most important causes of death were found to be impairment of coronary perfusion (33 patients, 27%), excessive pulmonary blood flow (23 patients, 19%), obstruction of pulmonary arterial blood flow (21 patients, 17%), neoaortic obstruction (17 patients, 14%), right ventricular failure (16 patients, 13%), bleeding (9 patients, 7%), infection (6 patients, 5%), tricuspid or common atrioventricular valve dysfunction (6 patients, 5%), sudden death from presumed arrhythmias (6 patients, 5%), and necrotizing enterocolitis (3 patients, 3%). In 26 patients (21%), more than one factor appeared responsible for death.

CONCLUSIONS

The leading causes of death after the Norwood procedure were found to be largely correctable surgical technical problems associated with perfusion of the lungs (36%), of the myocardium (27%), and of the systemic organs (14%).

Patch repair of subsemilunar conal septal defect resulting in severe left ventricular outflow tract obstruction

A subsemilunar conal septal defect was closed at 8 months of age with a redundant Dacron patch that bowed into the left ventricular outflow tract, resulting in severe subaortic stenosis and massive left ventricular hypertrophy. Mistaken for cardiomyopathy or myocarditis, this rare complication of subsemilunar ventricular septal defect patch closure led to orthotopic cardiac transplantation followed by death.

Absent right superior vena cava in visceroatrial situs solitus

Absence of the right superior vena cava (SVC) in visceroatrial situs solitus is rare (0.07% to 0.13% of congenital cardiovascular malformations), and little is known about the type and frequency of additional heart defects and arrhythmias. We reviewed previous publications and present 9 new cases. Based on 121 known cases, we found that this anomaly is typically characterized by: (1) persistence of the left SVC draining into the right atrium by way of the coronary sinus, and (2) left-sided azygos vein draining into the left SVC. Less constant features were: (3) additional cardiovascular malformations (46%), and (4) rhythm abnormalities (36%) that usually appeared related to the complications of old age. Since absence of the right SVC is clinically silent, its status should be assessed echocardiographically prior to invasive medical or surgical procedures. This is important to avoid various management difficulties during the following procedures: (1) implantation of a transvenous pacemaker, (2) placement of a pulmonary artery catheter for intraoperative or intensive care unit monitoring without fluoroscopy, (3) systemic venous cannulation for extracorporeal membrane oxygenation, (4) systemic venous cannulation for cardiopulmonary bypass, (5) partial or total cavopulmonary anastomoses; and (6) orthotopic heart transplantation and endomyocardial biopsies.

Right-sided high origin of diaphragm associated with accessory lobe of liver, lobulated right atrial appendage, and ipsilateral phrenic nerve hamartoma: a case report

A case of a rare condition of congenital right anterior high origin of the diaphragm in a stillborn fetus is reported. Associated findings at autopsy were a hornlike subdiaphragmatic intrathoracic accessory lobe of the liver and a lobulated right atrial appendage of the heart. At the superiormost aspect of the malpositioned right anterior diaphragmatic leaf a small phrenic nerve hamartoma was found. The phrenic nerve itself appeared small and not well developed. The phrenic nerve lesion may have been a concomitant or secondary hamartomatous change. Careful clinical and pathological search for concomitant anomalies in diaphragmatic lesions is emphasized.

Aortic outflow obstruction in visceral heterotaxy: a study based on twenty postmortem cases

Aortic outflow tract obstruction can complicate the clinical course and surgical management of patients with heterotaxy syndromes, but its anatomic basis has not been described in detail. In 20 postmortem cases with asplenia (n = 4) or polysplenia (n = 16), the anatomic causes of aortic outflow tract obstruction were absence of the subaortic conus in association with (1) narrowing of the subaortic outflow tract between the conal septum anteriorly and the common atrioventricular (AV) valve posteriorly in six (30%) patients; (2) aortic valvar atresia in four (25%), three with asplenia and one with polysplenia; (3) redundant AV valve leaflets in four (20%); (4) excessive AV valve fibrous tissue in four (20%); (5) marked hypoplasia of the mitral valve and left ventricle in two (10%); and (6) aneurysm of membranous septum in one (5%). One patient belonged to group (1) and (4). Aortic outflow tract obstruction was much more common with polysplenia (28%) than with asplenia (4%) (p < 0.001).

Multipolar endocardial mapping of the right heart using a basket catheter: acute and chronic animal studies

The development of catheter-based ablative techniques for primary atrial and ventricular arrhythmias is likely to be assisted by improved techniques for systematic endocardial activation sequence mapping. RA mapping using a multielectrode basket catheter has been shown to be feasible with minimal acute toxicity in a prior study. The objectives of the current study are to investigate: (1) the utility of the basket catheter for mapping RV activation; and (2) the evolution of acute endocardial lesions produced by basket catheter use in both the RA and RV over 4-8 weeks time. A flexible, 5-spoke basket catheter bearing 25 electrode pairs was placed in the RA (n = 9) or the RV (n = 13) in 22 juvenile sheep (22-56 kg). The catheter was deployed for 0.1-4.1 hr (RA) and 0.3-3.9 hr (RV). In 20 of these 22 animals, 32 recordings were made of filtered (30-250 Hz) bipolar electrograms and surface ECG. Electrograms were timed and used to construct activation sequences based on a schematic of catheter geometry. Hearts were examined either acutely (4 RA and 9 RV studies) or 4-8 weeks after the procedure (5 RA and 4 RV studies). One animal undergoing RA placement had an air embolism resulting in cardiac arrest immediately prior to basket placement; all other animals were stable during placement. RA electrograms of sufficient quality to determine activation time were recorded from 82% of pairs in RA maps, and RV electrograms from 89% of pairs in RV maps. Mean activation sequence duration in RV was 16 ms versus 47 ms in RA (P < 0.0001), making construction of RV maps more difficult. Acute postmortem studies of RV placement revealed a silent apical RV puncture in one animal. Superficial abrasion or ecchymosis of RV endocardium and/or tricuspid valve were noted in six animals. Postmortem exams in both RA and RV chronic studies showed healed endocardial lesions, with only superficial scarring. Rapid RV activation mapping using a basket catheter is feasible, but requires precision recording techniques. Endocardial abrasions produced in lambs both by RA and RV placement of the catheter are healed in < 4-8 weeks, with trivial residua. The multielectrode basket catheter may be applicable to the mapping of tachycardias originating in or involving the right ventricle.

Juxtaposition of the morphologically left atrial appendage in solitus and inversus atria: a study of 18 postmortem cases

Juxtaposition of the morphologically left atrial appendage (JLAA) was analyzed for the first time primarily morphologically, rather than primarily positionally. In a series of 18 postmortem cases, JLAA with solitus atria occurred in 16 (89%) cases, and JLAA with inversus atria was found in 2 (11%) cases. JLAA with solitus atria was always right-sided, whereas JLAA with inversus atria was left-sided. Thus the sidedness of the malposed (juxtaposed) LAA depended on the atrial situs, not on the type of ventricular loop (contrary to what was formerly thought). The anatomic features associated with JLAA are essentially the opposite of those with JRAA. JLAA was characterized by left atrial outlet obstruction (69%), left ventricular hypoplasia (67%), and aortic outflow tract obstruction (39%). JLAA usually has a hypoplastic left ventricle and normal conus, whereas JRAA typically has a hypoplastic right ventricle and abnormal conus.

The Holmes heart: historic associations and pathologic anatomy

In 1824, Andrew F. Holmes, later to become the first Dean of the Medical Faculty of McGill University, published the autopsy findings of a 21-year-old man who had died with chronic cyanosis and congestive heart failure. Autopsy revealed the first documented case of single ventricle. Reinspection and detailed photographs published for the first time show absence of the sinus (body or inflow tract) of the morphologically right ventricle (RV) and hence a single (unpaired) morphologically left ventricle (LV), double-inlet LV, infundibular outlet chamber (IOC), and normally related great arteries, with the pulmonary artery arising from the IOC and the aorta from the single LV. In view of its rarity, William Osler urged Maude Abbott to republish this case, which she did in 1901. Republication of the Holmes heart catalyzed the career of Maude Abbott, who then proceeded to become the world's authority on congenital heart disease until her death in 1940.

Juxtaposition of the morphologically right atrial appendage in solitus and inversus atria: a study of 35 postmortem cases

Juxtaposition of the atrial appendages has previously been classified positionally, left sided being more frequent than right sided. In our study of 35 postmortem cases, juxtaposition was analyzed morphologically for the first time. Juxtaposition of the morphologically right atrial appendage (JRAA) was always left sided with solitus atria (34 cases) but was right sided with inversus atria (1 case), the latter patient being the first documented case of JRAA with atrial inversion. Thus in patients with JRAA, the sidedness of the juxtaposition depends on the type of atrial situs that coexists. Frequent associated malformations included tricuspid valve anomalies (21 [60%] of 30), hypoplasia of the right ventricular sinus (26 [74%] of 35), and an abnormal conus (subaortic or bilateral) in 100%. Hypoplasia of the right ventricular sinus, plus malformation of the conus, appears to be important in the morphogenesis of JRAA.

Transposition of the great arteries [S,D,L]. Pathologic anatomy, diagnosis, and surgical management of a newly recognized complex

The transposition of the great arteries [S,D,L] complex is delineated for the first time from the anatomic, diagnostic, and surgical standpoints in this study of 26 cases: 16 surgical and 10 postmortem. Transposition of the great arteries with situs solitus of the viscera and atria (S), D-loop ventricles (D), and L-transposition (L) was characterized by six additional interrelated anomalies that largely determined surgical management: (1) ventricular septal defect, usually conoventricular, in 96%; (2) malalignment of the conal septum, typically leftward and posteriorly, in 80%; (3) right ventricular hypoplasia in 50%; (4) pulmonary outflow tract stenosis in 27%; (5) ventricular malposition, such as superoinferior ventricles, in 23%; and (6) absent left coronary ostium resulting in "single" right coronary artery in 23%. Complete surgical repair was done in 81% of the surgical patients with a 12.5% hospital mortality rate and no late deaths. When there was no pulmonary outflow tract stenosis and intracardiac anatomy was uncomplicated, we undertook anatomic repair before 1 month of age. However, when pulmonary outflow tract stenosis coexisted, complete repair was deferred until after age 1 year, our currently preferred operation being the REV procedure (réparation a l'etage ventriculaire). When complex intracardiac anatomy precluded biventricular repair, a palliative procedure was performed in 19% without mortality. Hence, this experience indicates that surgical management of patients with the transposition of the great arteries [S,D,L] complex is feasible.

Systemic and pulmonary venous connections in visceral heterotaxy with asplenia. Diagnostic and surgical considerations based on seventy-two autopsied cases

To facilitate the preoperative diagnosis and surgical management of visceral heterotaxy and asplenia, 72 postmortem cases were reviewed with particular attention focused on the systemic and pulmonary venous connections. The superior vena cava was bilateral in 51 cases (71%), but in 9 cases one of the superior venae cavae was partly or totally atretic. Patent bilateral superior venae cavae were found in 42 cases (58%) and the superior vena cava was unilateral in 21 (29%). Although the inferior vena cava was never interrupted, a prominent azygos vein was found in 6 cases (8%). Some hepatic veins drained separately from the inferior vena cava in 20 cases (28%). An intact coronary sinus was rare (2 cases, 3%). Anomalous pulmonary venous connection to a systemic vein was total in 42 (58%) of 72 and partial in 2 (3%) of 72, with obstruction in 24 (55%) of 44. Abnormal pulmonary artery branches (severe hypoplasia, localized stenosis, or discontinuity) were present in 21 (29%), and these obstructive arterial anomalies were associated with a significantly higher prevalence of anomalous pulmonary venous connection (p < 0.01) and of pulmonary venous obstruction (p < 0.01). Cardiac pulmonary venous connections were found in 28 (39%), with the pulmonary veins and the inferior vena cava entering the same atrium in 10 (36%) of 28.

Partial or total direct pulmonary venous drainage to right atrium due to malposition of septum primum. Anatomic and echocardiographic findings and surgical treatment: a study based on 36 cases

The clinical and anatomic findings in 36 patients (21 postmortem cases and 15 living patients) with partially anomalous (16 [44%]) or totally anomalous (20 [56%]) pulmonary venous drainage directly to the right atrium constitute the material basis of this report. Displacement of septum primum--leftward in atrial situs solitus or rightward in atrial situs inversus--was present in all and appeared responsible for the anomalous pulmonary venous drainage. The pulmonary veins were connected with what normally constitutes the posterior wall of the left atrium, which became incorporated into the right atrium because of atrial septal displacement. This abnormality occurred predominantly in patients with visceral heterotaxy, usually with polysplenia, or rarely with asplenia or a normally formed spleen. Poor development or absence of septum secundum appeared responsible for the malposition of septum primum. Echocardiographic recognition of the displacement of septum primum facilitated surgical management.

Tetralogy of Fallot [S,D,I]: successful repair without a conduit

Tetralogy of Fallot [S,D,I] is a recently discovered form of tetralogy with solitus atria (S) and D-loop ventricles (D), but with inverted normally related great arteries (I). Because of infundibuloarterial inversion, the right coronary artery must traverse the stenotic pulmonary outflow tract, increasing the risk of surgical trauma to the right coronary artery. Here we report a case of successful surgical repair of tetralogy of Fallot [S,D,I] without the use of an extracardiac conduit.

Sinus venosus defects: unroofing of the right pulmonary veins--anatomic and echocardiographic findings and surgical treatment

To clarify the nature of so-called sinus venosus atrial septal defects, the echocardiographic findings in 41 patients undergoing surgery at Children's Hospital, Boston, from March 1986 to October 1992 were reviewed, and four heart specimens with this anomaly were reassessed. Our conclusion, clearly demonstrated echocardiographically, is that sinus venosus defects result from a deficiency in the wall that normally separates the right pulmonary veins from the SVC and the RA. This deficiency unroofs the right pulmonary veins, permitting them to drain into the SVC or into the RA. An interatrial communication is almost always present and is posterior or posterosuperior to the fossa ovalis. This interatrial communication is the orifice of the unroofed right pulmonary veins rather than a defect in the atrial septum.

Late enlargement of radiofrequency lesions in infant lambs. Implications for ablation procedures in small children

BACKGROUND

Despite the current clinical use of radiofrequency (RF) catheter ablation in infants, the acute and late effects of RF lesion production in immature myocardium remain unknown. This study was specifically designed to investigate the pathology of RF lesions in developing sheep myocardium.

METHODS AND RESULTS

In study 1, RF lesions were made on the epicardial left ventricular surface of the beating heart in 15 sheep, 5 approximately 4 weeks of age (11.0 +/- 1.0 kg) and 10 approximately 8 weeks of age (23.8 +/- 3.4 kg), to assess the effects of RF application duration (10 to 90 seconds) and electrode tip temperature (45 degrees to 90 degrees C) on lesion size in immature myocardium. Lesion width and depth increased asymptotically with RF duration, to 7.0 +/- 0.7 and 4.8 +/- 1.0 mm at 90 seconds, respectively. The time to reach one-half lesion size was 6.5 seconds for width and 12.0 seconds for depth. Lesion width increased nearly linearly with tip temperature above 50 degrees C, but depth followed a sigmoid relation, with no increase above 80 degrees C. In study 2, RF lesions were made in all four cardiac chambers under fluoroscopic guidance in 19 infant sheep (10.9 +/- 1.4 kg). Lesion sizes and histological characteristics were assessed acutely (acute, n = 5), at 1.07 +/- 0.02 months (1 month, n = 5), and at 8.5 +/- 0.5 months (late, n = 9). Atrial and ventricular lesions but not atrioventricular groove lesions apparently increased in size during the follow-up period. Atrial lesions width increased from 5.3 +/- 0.5 to 8.7 +/- 0.7 mm at 1 month (164%) but did not increase further at late follow-up, while ventricular lesion width increased from 5.9 +/- 0.8 to 10.1 +/- 0.7 mm (171%) at late follow-up but was not significantly changed at 1 month. Histological evaluation revealed replacement of normal myocytes with fibrous and elastic tissue at 1 month and late follow-up in all locations but also demonstrated a poorly delineated border with multiple extensions of fibrous and elastic tissue into surrounding normal myocardium in late ventricular lesions.

CONCLUSIONS

RF lesion formation in immature sheep myocardium is similar to that in adult myocardium acutely but is associated with late lesion enlargement and fibrous tissue invasion of normal myocardium. These findings may have implications for clinical RF ablation procedures in infants.

Conal anatomy in 119 patients with d-loop transposition of the great arteries and ventricular septal defect: an echocardiographic and pathologic study

OBJECTIVES

We sought to study the range of conal morphology in transposition of the great arteries with ventricular septal defect and their embryologic and surgical implications.

BACKGROUND

Conal anatomy in transposition of the great arteries and ventricular septal defect is variable and might affect surgical repair.

METHODS

Conal anatomy was explored using two-dimensional echocardiography in 119 patients with transposition of the great arteries and a large ventricular septal defect who presented between 1984 and 1991. The influence of conal anatomy on surgical technique was determined by review of the operative reports. Specimens of transposition of the great arteries with unusual conal anatomy were selected from the Cardiac Registry for comparison with the echocardiograms.

RESULTS

One hundred five patients (88.2%) had subaortic conus only with no subpulmonary conus (Group 1). Subarterial conus was present bilaterally in eight patients (6.7%) (Group 2). Four patients (3.4%) had only subpulmonary conus with no (or minimal) subaortic conus (Group 3). Among these four patients, the aorta was posterior to the pulmonary artery in one patient, side by side relative to the pulmonary artery in two patients and slightly anterior in the fourth patient. Subarterial conus was absent bilaterally in two patients (1.7%) (Group 4); the aorta was slightly posterior in one and side by side with the pulmonary artery in the other.

CONCLUSIONS

This variability of conal anatomy in transposition of the great arteries with ventricular septal defect implies four mechanisms by which transposition can occur. The conal anatomy appeared to affect surgical repair in Groups 1 and 2 insofar as it influenced ventricular outflow tract obstruction. In Groups 3 and 4, an arterial switch operation was performed in four of the six patients. The posterior location of the aorta obviated the need for the Lecompte maneuver in two of these four patients. In the remaining two cases in Groups 3 and 4, the condition was repaired by directing the left ventricular outflow across the ventricular septal defect to the aorta using a patch, with or without placement of a conduit from the right ventricle to the pulmonary artery.

Surgical management of late right ventricular failure after Mustard or Senning repair

BACKGROUND

Information on surgical management and outcome in patients who develop symptomatic right ventricular failure after prior Mustard or Senning operations is limited.

METHODS AND RESULTS

From March 1987 to March 1991, 10 patients 3.6-23.5 years old (median, 7.0 years) with transposition of the great arteries and prior Mustard (six patients) or Senning (four patients) repairs (performed at ages 2 months to 5 years; median, 6 months) underwent surgical intervention for symptomatic right ventricular failure. In five of 10 patients, anatomic correction with either an arterial switch operation (three patients) or a pulmonary artery-to-aorta anastomosis and right ventricle-to-pulmonary artery conduit (two patients) was performed. Before anatomic correction in these five patients, four of five patients had a pulmonary artery band to prepare the left ventricle. The interval between preparation and correction ranged from 8 days to 12 months (median, 2 months). One patient died after an arterial switch operation. In the remaining five patients, coexisting left ventricular dysfunction precluded anatomic correction; all five patients survived cardiac transplantation. Survival for the entire group of 10 patients is 90%, and the median postoperative hospital stay was 17 days. During follow-up (12-62 months; median, 27 months), there were no deaths. Neoaortic insufficiency after anatomic correction was common (mild in one patient, moderate in two patients, and severe in one patient who required aortic valve replacement 4 months after surgery). In the transplantation group, one patient developed lymphoma 3 months after transplantation but is currently in remission after reduction of immunosuppression.

CONCLUSIONS

In patients who develop late right ventricular failure after Mustard or Senning repair, surgical intervention with either anatomic correction or cardiac transplantation can be done with acceptable morbidity and low mortality. Neoaortic valve insufficiency demands close follow-up after anatomic correction.

Morphometry of human coronary capillaries during normal growth and the effect of age in left ventricular pressure-overload hypertrophy

BACKGROUND

In adults, acquired pressure-overload left ventricular hypertrophy can result in myocardial ischemia, which may be due in part to insufficient capillary growth during development of hypertrophy. The coronary microvascular response to congenital pressure-overload hypertrophy in children has not been previously characterized.

METHODS AND RESULTS

Average capillary density and heterogeneity of capillary spacing were measured in 63 postmortem human hearts with left ventricular hypertrophy and control hearts without heart disease. Pathology specimens were chosen that had left ventricular hypertrophy caused by 1) congenital isolated aortic valve stenosis in infants less than 1 year old at death, children 9-14 years old, and adults 15-30 years old; 2) congenital isolated coarctation of the aorta in adults 15-39 years old; and 3) acquired aortic stenosis in adults 51-86 years old. Major findings of the study were: 1) Human left ventricular capillary density and heterogeneity of capillary spacing are similar to other mammalian species. 2) Capillary density is higher in infants (3,315 +/- 85 capillaries per square millimeter), decreases with increasing heart weight during normal growth in early childhood (children, 2,388 +/- 75 capillaries per square millimeter, p less than 0.05), and thereafter remains relatively constant. 3) Capillary density with left ventricular hypertrophy is dependent on the age of onset. Congenital aortic stenosis and coarctation are characterized by an increase in capillary supply proportional to myocyte volume, maintaining capillary density similar to control hearts. Adults with acquired aortic stenosis have decreased capillary density (1,671 +/- 66 capillaries per square millimeter, p less than 0.01 versus control).

CONCLUSIONS

Pressure-overload left ventricular hypertrophy in children demonstrates proportional capillary angiogenesis, whereas in adults, hypertrophy appears to be associated with failure of compensatory angiogenesis.

Pulmonary valve-moderator band distance and association with development of double-chambered right ventricle

Double-chambered right ventricle (DCRV), a form of right ventricular outflow obstruction that sometimes accompanies a ventricular septal defect (VSD), is associated with superior and rightward displacement of the septal insertion of the moderator band. It was hypothesized that this superior displacement is present and identifiable by echocardiography in patients with a VSD even before right ventricular outflow tract obstruction develops. Eight patients who had a previous echocardiographic study showing a VSD alone were echocardiographically diagnosed as having DCRV. Their initial echocardiographic studies were reviewed, and superior displacement of the moderator band was quantified by measuring the distance between the pulmonary valve and moderator band, normalized to tricuspid anulus diameter. These measurements were compared with those from the initial studies of the following 3 other groups: (1) an age-matched group of 10 patients with no structural heart disease; (2) an age-matched group of 10 patients with a VSD who did not develop DCRV; and (3) a group (not age-matched) of 10 patients with VSD and DCRV in whom subpulmonary obstruction was present on the initial study. The 8 patients who eventually developed subpulmonary obstruction had significant superior displacement of the moderator band at the time of their initial echocardiogram compared with that of the 2 age-matched control groups (p less than 0.01). In contrast, there was no significant difference in moderator band displacement between these patients and the 10 with DCRV who already had right ventricular outflow obstruction at their initial study (p = not significant).(ABSTRACT TRUNCATED AT 250 WORDS)

The arterial switch operation in transposition of the great arteries: anatomic indications and contraindications

1. The arterial switch procedure is now the operation of choice for typical D-transposition of the great arteries at The Children's Hospital, Boston, USA, the operative mortality rate since 1985 being 3%. 2. There are many anatomic considerations suggesting the morphologically left ventricle (LV) may well be a better systemic pump than the morphologically right ventricle (RV) which, if true, would favor the arterial switch procedure as opposed to an atrial switch operation: (1) The LV consists almost entirely of the sinus or pumping portion, and has only a minimal distal infundibular (conal) component. The RV, by contrast, has a relatively much larger infundibular component, the primary function of which is to prevent regurgitation rather than to pump. (2) Phylogenetically, the LV is the ancient "professional" pump. By contrast, the RV is a comparatively recent modification of the bulbus cordis. (3) The LV is a two-coronary ventricle, whereas the RV is a one-coronary ventricle. (4) The LV has relatively much more compact myocardium (stratum compactum) than does the RV. (5) The mitral valve leaflets are better designed to occlude a circular systemic atrioventricular orifice than are the tricuspid valve leaflets. (6) The papillary muscles of the LV are large, paired, well balanced, and both arise from the same ventricular wall--the LV free wall. By contrast, the papillary muscles of the RV are comparatively small, numerous, unbalanced, and arise from both ventricular septal and free walls. Hence, dilatation of the LV does not pull the LV papillary muscles apart, whereas dilatation of the RV does pull the RV muscles apart, favoring the development or exacerbation of tricuspid regurgitation. (7) The LV has two conduction system radiations, whereas the RV has only one. 3. The current anatomic contraindications to the arterial switch operation in typical D-TGA include the following: (1) an unprepared LV; (2) an aortic intramural left coronary artery arising from the right coronary sinus of Valsalva; (3) pulmonary outflow tract stenosis (with small annulus and subvalvar obstruction) or atresia; (4) aortic outflow tract stenosis (with small annulus and subvalvar obstruction) with tubular hypoplasia of the aortic arch and preductal coarctation; (5) tricuspid or mitral atresia; (6) marked underdevelopment or absence of either the RV sinus or the LV sinus; and; (7) 2 major anomaly of the systemic and/or pulmonary veins, as in the heterotaxy syndrome with asplenia.(ABSTRACT TRUNCATED AT 400 WORDS)

Straddling mitral valve with hypoplastic right ventricle, crisscross atrioventricular relations, double outlet right ventricle and dextrocardia: morphologic, diagnostic and surgical considerations

The clinical, surgical and morphologic findings in five cases of a rare form of straddling mitral valve are presented. Three patients were diagnosed by two-dimensional echocardiography, cardiac catheterization and angiocardiography and two had diagnostic confirmation at autopsy. All five cases shared a distinctive and consistent combination of anomalies: 1) dextrocardia; 2) visceroatrial situs solitus, concordant ventricular D-loop and double outlet right ventricle with the aorta positioned to the left of and anterior to the pulmonary artery; 3) hypoplasia of right ventricular inflow (sinus) with tricuspid valve stenosis or hypoplasia; 4) large right ventricular infundibulum (outflow); 5) malalignment conoventricular septal defect; 6) straddling mitral valve with chordal attachments to the left ventricle and right ventricular infundibulum; 7) severe subpulmonary stenosis with well developed pulmonary arteries; and 8) superoinferior ventricles with crisscross atrioventricular (AV) relations. The degree of malalignment between the atrial and ventricular septa was studied quantitatively by measuring the AV septal angle projected on the frontal plane. The AV septal angle in the two postmortem cases was 150 degrees, reflecting marked malalignment of the ventricles relative to the atria. This AV malalignment appears to play an important role in the morphogenesis of straddling mitral valve. As judged by a companion study of seven postmortem cases, the more common form of straddling mitral valve with a hypertrophied and enlarged right ventricular sinus had less severe ventricular malposition than did the five rare study cases with hypoplastic right ventricular sinus. A competent mitral valve, low pulmonary vascular resistance and low left ventricular end-diastolic pressure were found at cardiac catheterization in the three living patients who underwent a modified Fontan procedure and are doing well 2.2 to 5.8 years postoperatively.

Cardiac rhabdomyoma. Rare cause of fetal death

Two cases of nonimmune hydrops fetalis and fetal death associated with cardiac rhabdomyoma are reported. Case 1 presented with fetal supraventricular tachycardia, and cardiac rhabdomyoma was accurately diagnosed by fetal echocardiography. Autopsy revealed multiple rhabdomyomata involving the right atrial free wall, the sinoatrial node, and the left ventricle. The left circumflex coronary artery was extrinsically compressed by adjacent tumor tissue, causing left ventricular myocardial infarction. Case 2 had a unique, pedunculated, ball-like rhabdomyoma that almost totally occluded the mitral orifice. The causes of fetal death in patients with cardiac rhabdomyoma are analyzed and the possibility of fetal surgical management is proposed.

Two-dimensional and Doppler echocardiographic and pathologic characteristics of the infantile Marfan syndrome

Since the clinical, 2-dimensional and Doppler echocardiographic and pathologic findings in infantile Marfan syndrome have not been documented in detail, a study of 9 such infants was performed. The previously reported 64 cases were reviewed and the salient findings in 22 additional cases were discussed. The age at diagnosis in our 9 cases ranged from birth to 12 months (mean 2.7 months). Mitral valve prolapse was demonstrated in all, with mitral regurgitation in 8. Tricuspid valve prolapse was present in 8, with tricuspid regurgitation in 6. Marked aortic root dilatation was present in all, and was progressive. The aortic root assumed a "clover leaf" appearance in the parasternal short-axis view. Aortic regurgitation was documented initially in 1 patient, and developed during follow-up in 4 of 7 infants. Dilation of the pulmonary arterial root and pulmonary regurgitation were found in 3 of 7 infants. Severe heart failure associated with mitral or tricuspid regurgitation was present in 7 of the 9 patients. Four infants died during the first year of life. The salient pathologic features were myxomatous thickening and redundancy of the mitral and tricuspid leaflets, marked elongation of chordae tendineae and prominent dilatation of the aortic and pulmonary roots. Histologically, the collagen and elastic fibers were severely disrupted, disarrayed and fragmented with increased interstitial ground substance. These data document that infantile Marfan syndrome is characterized by clinical and morphologic features that are distinctly different from the classic syndrome seen in adolescents and adults. The aforementioned findings should facilitate early clinical and echocardiographic diagnosis of infantile Marfan syndrome.