Discordant Atrioventricular Connections Research Articles

The role of Fontan's procedure and aortic translocation in the surgical management of patients with discordant atrioventricular connections, interventricular communication, and pulmonary stenosis or atresia

A variety of surgical strategies have been utilized in attempts to accomplish long-term haemodynamic stability in patients with cardiac anomalies characterized by discordant atrioventricular connections, ventricular septal defect, and severe sub-pulmonary obstruction. The majority of these patients have what is commonly referred to as congenitally corrected transposition, together with a ventricular septal defect and pulmonary stenosis or atresia, in the setting of either usual or mirror imaged arrangement of the atrial chambers and the other organs of the body. A smaller sub-group, with discordant atrioventricular connections and double outlet right ventricle, with severe sub-pulmonary obstruction or pulmonary atresia, present similar physiology, and a comparable surgical challenge.

The nomenclature, definition and classification of discordant atrioventricular connections

During the process of creation of a bidirectional crossmap between the system emerging, on the one hand, from the initiative sponsored by the Congenital Heart Committees of the European Association for Cardio-Thoracic Surgery and the Society of Thoracic Surgeons, and on the other hand, from that formulated by the Coding Committee of the European Association for Pediatric Cardiology, the Nomenclature Working Group has successfully created the International Paediatric and Congenital Cardiac Code. As would be expected, during the process of crossmapping it became clear that, for most lesions, the European Pediatric Cardiac Code was more complete in its description of the diagnoses, while the International Congenital Heart Surgery Nomenclature and Database Project was more complete in its description of the procedures. This process of crossmapping exemplifies the efforts of the Nomenclature Working Group to create a comprehensive and all-inclusive international system for the naming of paediatric and congenital cardiac disease, the International Pediatric and Congenital Cardiac Code. Although names and classification for paediatric and congenital cardiac disease will continue to evolve over time, we are now closer than ever to reaching uniform international agreement and standardization. The International Paediatric and Congenital Cardiac Code can be downloaded from the Internet, free of charge, at www.ipccc. net.

The classical and the one-and-a-half ventricular options for surgical repair in patients with discordant atrioventricular connections

The classical option for surgical repair in patients with congenitally corrected transposition takes advantage of the physiologic correction provided by nature. At the end of the surgical procedures, however, the morphologically right ventricle remains as the systemic ventricle. Surgical intervention is essentially the correction of associated lesions, including closure of ventricular septal defects, pulmonary valvotomy, placement of a conduit from the morphologically left ventricle to the pulmonary arteries, replacement of the morphologically tricuspid valve, and placement of pacemakers for third degree atrioventricular block. For many years, the classical approach was the “standard” surgical approach.1–4More recently, newer alternatives have become available, including forms of anatomic repair, the “one-and-a half” ventricular option, and conversion to the Fontan circulation. The goal of anatomic repair is to craft connections such that the morphologically left ventricle becomes the systemic ventricle. Surgical techniques that accomplish this are a Rastelli procedure combined with an atrial baffle,5and the combination of an arterial switch with an atrial baffle, be it a Mustard or Senning procedure.6

Anatomy and echocardiography of discordant atrioventricular connections

The most appropriate way of describing the congenital cardiac malformations unified because the atrial chambers are joined across the atrioventricular junctions to morphologically inappropriate ventricles has long been contentious. In the past, the lesions have been described in such arcane terms as mixed levocardia,1 while “ventricular inversion” still retains it currency in some circles. As we will show in this review, the abnormal arrangements at the atrioventricular junctions can be found with various patterns, but most frequently the patients also have the arterial trunks arising from morphologically inappropriate ventricles. This combination is best described as congenitally corrected transposition, and will form the focus of our review. It is salutary to note that, when von Rokitansky gave the first description of this combination,2 one of his illustrations was ideally suited to aid the understanding of modern-day echocardiographers (Fig. 1). We hope to emulate von Rokitansky in our own review.

Functional biventricular repair using left ventricle-pulmonary artery conduit in patients with discordant atrioventricular connections and pulmonary outflow tract obstruction-does conduit obstruction maintain tricuspid valve function?

The aim of the study is to determine whether function of the tricuspid valve placed for the systemic circulation is related to left ventricular pressure supporting the pulmonary circulation after functional repair for atrioventricular discordance. Right ventricular volume and tricuspid regurgitation (TR) were investigated, in relation to left ventricular pressure, in 15 patients with this malformation who underwent functional biventricular repair with left ventricle-pulmonary artery conduit. After the functional biventricular repair, ratio of systolic left ventricular pressure to right ventricular one (LVP/RVP) was 0.58+/-0.24 and right ventricular end-diastolic pressure (RVEDV) significantly increased from 104+/-24 to 137+/-39% of normal predicted value (P = 0.015). Five patients with LVP/RVP>0.6 were free from TR, however, six of seven with LVP/RVP<0.6 developed TR. Three patients required eventual tricupid valve replacement. Conduit replacement was required in seven patients and five were assessed similarly. After the conduit replacement, LVP/RVP decreased from 1.08+/-0.34 to 0.58+/-0.14 and RVEDV increased significantly from 87+/-24 to 129+/-19% (P = 0.011). One patient with postoperative LVP/RVP of 0.36 developed moderate TR. Mild obstruction at the pulmonary channel is not necessarily an evil after functional biventricular repair for this malformation, in terms of TR and right ventricular dilatation.

Dextrocardia: an analysis of cardiac structures in 125 patients

Background: Dextrocardia is associated with multiple and complex congenital cardiac anomalies. Precise anatomical diagnosis is essential for successful surgery. Spectrum of congenital malformations in cases of dextrocardia is based primarily on two-dimensional echocardiographic studies. The purpose of the current study was to use colour Doppler echocardiography in large number of patients. Methods: Patients of dextrocardia were studied retrospectively, by reviewing database of our echocardiographic laboratory over last 10 years. Standard criteria for diagnosis of situs were used. Detailed segmental analysis for cardiac anatomy and associated malformations was done using previously suggested and well accepted terms and definitions. Cardiac anatomy was confirmed on catheterization and during surgery in few cases. Results: Of total 125 patients, dextrocardia was most common with situs inversus (39.2%) followed by situs solitus (34.4%) and situs ambiguous [26.4% (right isomerism in 18.4% and left isomerism in 8.0%)]. Mean age was 9.2±11.2 years (range; 3 days to 60 years), 82 males and 43 females. In situs inversus dextrocardia, majority (73.4%) had concordant atrioventricular (AV) connections while discordant AV connections and univentricular atrioventricular connections (UVAVC) were present in 12.2 and 14.3% patients, respectively. Majority of patients with concordant AV connections (72.2%) also had concordant VA (ventriculo–arterial) connections (conotruncal anomalies were commonest). Similarly, majority of patients with discordant AV connections (66.7%) also had discordant VA connections. Commonly (44.9%), these patients presented with decreased pulmonary blood flow (Qp). Total 28.6% patients had normal intracardiac anatomy (10.2% presented with rheumatic heart disease). In situs solitus dextrocardia, majority (51.2%) had AV concordance while discordant AV connections and UVAVC were present in 41.9 and 7.0% patients, respectively. In patients with concordant AV connections, majority (77.2%) had VA concordance (majority presented with increased Qp due to pre or post-tricuspid shunts). Similarly, majority of patients with discordant AV connections (88.9%) also had discordant VA connections (88.9% presented with decreased Qp). Only 7.0% patients with situs solitus dextrocardia had normal intracardiac anatomy. The striking features of right isomerism were male predominance (male:female ratio 2.2:1), cyanosis with decreased Qp in 86.9%, and high incidence of UVAVC and venous system anomalies (39.1% each). Striking features of left isomerism were biventricular ambiguous AV connections in all except one, presentation with increased Qp in 60.0% and presence of inferior vena caval interruption in 60.0% patients. Conclusions: Present study, largest study of dextrocardia till date reconfirms that these patients have variable intracardiac anatomy depending upon their situs and types of segmental connections. These patients can present with different haemodynamic subsets, which can be correctly identified by colour Doppler echocardiography. Diagnostic accuracy and a better understanding of the various types of dextrocardia are essential, since improved surgical techniques have made it possible to correct many of these complex abnormalities.

Technical aspects of the combined arterial switch and senning operation for congenitally corrected transposition of the great arteries

Congenitally corrected transposition of the great arteries (ccTGA) is a rare defect characterized by discordant atrioventricular and ventriculoarterial connections. Symptoms result from one or a combination of associated cardiovascular malformations, including ventricular septal defect, pulmonary stenosis or atresia, and tricuspid valve dysfunction. Survival of patients with ccTGA is often determined by the associated anomalies, but even in isolation ccTGA results in a diminished life expectancy. Regurgitation of the tricuspid valve and decreased morphologic right ventricular function tend to develop and worsen over time. Anatomic repair by double switch technique may improve survival of patients with ccTGA by establishing the morphologic left ventricle in the systemic circulation.

Technical aspects of the combined arterial switch and senning operation for congenitally corrected transposition of the great arteries.

Congenitally corrected transposition of the great arteries (ccTGA) is a rare defect characterized by discordant atrioventricular and ventriculoarterial connections. Symptoms result from one or a combination of associated cardiovascular malformations, including ventricular septal defect, pulmonary stenosis or atresia, and tricuspid valve dysfunction. Survival of patients with ccTGA is often determined by the associated anomalies, but even in isolation ccTGA results in a diminished life expectancy. Regurgitation of the tricuspid valve and decreased morphologic right ventricular function tend to develop and worsen over time. Anatomic repair by double switch technique may improve survival of patients with ccTGA by establishing the morphologic left ventricle in the systemic circulation.

Radiofrequency ablation of atrioventricular accessory pathways associated with discordant atrioventricular connections.

Discordant atrioventricular connections associated with Wolff-Parkinson-White syndrome increase the challenge of radiofrequency ablation. We report the results and techniques of radiofrequency ablation in three patients with discordant atrioventricular connections, including one patient having double outlet right ventricle with atrioventricular reentry tachycardias. There were two males and one female, aged 14 and 22 years old. We found four accessory pathways during our electrophysiological studies, with two of them manifest on the electrocardiogram, corresponding to left paraseptal and right midseptal regions. The electrophysiological study confirmed this localization, and showed two concealed accessory pathways in the right and left paraseptal regions. Radiofrequency ablation was successful in all cases without recurrence at a mean follow-up of 18.6 months. No complications were observed during the procedures. We conclude that radiofrequency ablation is feasible and effective in the ablation of accessory pathways in patients with discordant atrioventricular connections.

Living morphogenesis of the ventricles and congenital pathology of their component parts.

Living morphogenetic studies show that each definitive ventricle is constructed from different primitive cardiac segments, and each has its specific anatomical features. These ventricular segments are the atrioventricular junction; the primitive inlet segment, part of the primary heart tube, which initially provides the inlets of each ventricle; the primitive outlet segment, which gives rise to both ventricular outlets; and the apical trabeculated regions of the right and left ventricles which grow from the primary heart tube, respectively. In this review, we describe regional pathology based on the relationship of these primitive ventricular components. We propose that the abnormal morphogenesis of one of these segments gives origin to regional ventricular pathology. For example, abnormal embryogenesis of the atrioventricular canal produces malformations of the atrioventricular junctions, such as double inlet ventricle, absence of one atrioventricular connection, and straddling and overriding atrioventricular valves. Similarly, abnormal morphogenesis of the primitive outlet segment gives rise to malformations of the subarterial region of each ventricle, along with the valves guarding these vessels. The principal anatomical features of these malformations of the ventricular inlets and outlets are described, and their possible morphogenesis is discussed. Due to the fact that the apical trabeculated region of each ventricle arises from a separate primitive segment, each ventricle can be identified according to the pattern of its apical trabeculations. This feature is crucial in the elucidation of complex congenital pathology, such as discordant atrioventricular connections.

Anesthetic management of a pregnant patient with congenitally corrected transposition of the great arteries for labor and vaginal delivery

A patient with congenitally corrected transposition of the great arteries (CCTGA), which is a rare form of congenital heart disease that is characterized by discordant atrioventricular and ventriculoarterial connections, was admitted for induction of labor at 40 weeks’ gestation. This patient was first diagnosed with CCTGA at 20 weeks’ gestation and had experienced recurrent supraventricular tachycardia (SVT) during her pregnancy. An early epidural infusion of local anesthetic and opioid was administered to decrease maternal catecholamine release and prevent tachycardia associated with labor pain. Noninvasive blood pressure, continuous lectrocardiography, and pulse oximetry were monitored, and supplemental oxygen was provided. Various cardiac medications were made immediately available to promptly treat a SVT if necessary. The patient remained hemodynamically stable throughout labor and vaginal delivery. The anatomical defects of CCTGA, associated conditions, physiologic concerns, and treatment options are reviewed.

The feasibility of complete anatomical correction in the setting of discordant atrioventricular connections

OBJECTIVETo evaluate the feasibility of anatomical correction based on morphological and echocardiographic findings in patients and preserved hearts with discordant atrioventricular connections.DESIGNA retrospective study with clinicomorphological correlations to assess potential...

Morphology of hearts undergoing Fontan repair

AbstractBackgroundNotwithstanding the controversies evoked by the term “single ventricle”, most patients with this condition would undergo the Fontan procedure. In addition, there is a large group of patients in whom a biventricular repair would be abandoned in favour of a univentricular one because of the presence of unfavourable morphologic features. There is a need for a uniformly acceptable system of nomenclature that would permit precise description and classification of hearts with complex malformations to facilitate reporting and help in understanding the reasons for choosing a univentricular repair.MethodsEchocardiographic, angiographic and operative records of 240 patients undergoing the Fontan procedure were analysed.ResultsOut of the 104 patients with univentricular atrioventricular connections, 2 ventricles were discernible in all but 3 patients. A Fontan repair was performed in 136 patients with biventricular atrioventricular connections because of the presence of a hypoplastic ventricle in 52 patients and a non-committed ventricular septal defect in the remaining 84.ConclusionsThe Fontan operation is probably the only definitive treatment option for patients with univentricular atrioventricular connections. The decision to perform a univentricular repair in preference to a biventricular one in hearts with biventricular atrioventricular connections is based on the presence of a hypoplastic ventricle or a non-reroutable ventricular septal defect. This decision is subjective. In hearts with discordant atrioventricular connections and pulmonary stenosis, we prefer the Fontan operation to the classical repair.

Surgical correction of a patient with discordant atrioventricular and concordant ventriculo-arterial connections

AbstractThe combination of discordant atrioventricular and concordant ventriculoarterial connections is an extremely rare entity, with only 8 cases of successful surgical repair being previously reported. Although from the clinical standpoint this anomaly is similar to complete transposition, this unusual combination is clearly suited by its morpho-physiological features to an atrial rather than an arterial switch procedure. A 17-year-old boy with this malformation, associated also with severe pulmonary hypertension, underwent a palliative Senning procedure, leaving the ventricular septal defect open and banding the pulmonary trunk. Postoperatively, hypoxemia was markedly improved, and was associated with a reduction of the level of pulmonary hypertension, contributing to marked symptomatic improvement.

Discordant atrioventricular and ventriculoarterial connections with partially unguarded left-sided atrioventricular orifice and aortic atresia

AbstractCongenitally unguarded morphologically tricuspid valvar orifice is a rare abnormality, usually associated with pulmonary atresia. We describe such a case found in association with discordant atrioventricular and ventriculoarterial connections in which the aortic valve was atretic. Presentation was with respiratory distress due to severe cardiac failure after birth. Echocardiography demonstrated a dilated systemic ventricle with poor function, left atrial enlargement, and aortic atresia. The clinical findings were confirmed at autopsy.

Coexistence of atrioventricular block and Wolff-Parkinson-White syndrome in children

AbstractCoexistence of atrioventricular block and Wolff-Parkinson-White syndrome is uncommon, but may occur in children, particularly with certain congenital heart defects. Our study describes 5 children who had pre-excitation and underlying disturbance of atrioventricular conduction. All of these patients had structural heart defects, consisting of discordant atrioventricular connections in three, double inlet left ventricle in one, and a ventricular septal defect associated with straddling of the tricuspid valve in the other. In 4 of the patients, the presence of atrioventricular block was initially masked by the pre-excitation. When the conduction through an accessory pathway is lost, the child may be left with atrioventricular block, which is poorly tolerated in the setting of complex cardiac anatomy. Awareness of this association of Wolff-Parkinson-White syndrome and atrioventricular block is important in understanding the natural history and the management of children with congenital heart defects that are associated with tenuous atrioventricular conduction.

The coronary arteries in hearts with discordant atrioventricular connections

Gross morphologic study of 14 hearts with congenitally corrected transposition or discordant atrioventricular connections and double-outlet right ventricle or pulmonary atresia disclosed consistently the origins of the coronary arteries from two aortic sinuses. With usual atrial arrangement, the artery arising in sinus 1 (right-hand facing), as seen from the noncoronary aortic sinus, supplied the morphologically right ventricle. Coronary blood supply to the morphologically left ventricle usually came from sinus 2 (left-hand facing), although in two hearts the circumflex branch was a continuation of the artery from sinus 1. The sinus nodal artery arose from the circumflex coronary artery, and histologic studies of two hearts demonstrated that blood supply to the anterior atrioventricular node also came from this vessel. Early branching and entrapment in fat or right ventricular muscle, as well as malalignment of aortic and pulmonary sinuses, occurred frequently. These findings may have implications for coronary arterial transfer in the double switch operation in hearts with discordant atrioventricular connections. (J T HORAC C ARDIOVASC S URG 1996;111:988-97)

Supravalvar stenosing tricuspid ring in congenitally corrected transposition

SummaryWe report an unusual case with discordant atrioventricular and ventriculoarterial connections. In addition to the commonly associated intracardiac anomalies ofventricular septal defect and subpulmonary tissue tags, a supravalvar ring was present above the left-sided, morphologically tricuspid valve. This case highlights the value of color flow Doppler echocardiography in making the diagnosis, particularly as the supravalvar ring was seen poorly angiographically.

Surgical anatomy of the coronary circulation in hearts with discordant atrioventricular connections

We examined the arrangement of the coronary arterial and cardiac venous systems in 46 specimens with discordant atrioventricular connections so as to identify any structural abnormalities and to consider their surgical implications in terms of anatomical biventricular repair. Grossly abnormal arterial courses were seen in 11 hearts (24%). A substantial branch supplying the morphologically right ventricular outflow tract, which could restrict a ventriculotomy, was found in 61% of cases. The coronary sinus received all the morphologically right ventricular veins, as well as the posterior interventricular vein, in 40 hearts, this pattern being in contrast to the pattern in the normal heart. The morphologically left ventricular and anterior interventricular veins, all of which drain via the coronary sinus in the normal heart, were frequently connected independently to the morphologically right atrium in the specimens with discordant connections, the drainage occurring through the spaces between the pectinate muscles. These direct drainages are at risk of potential damage either by extensive intra-atrial maneuvers or by postoperative intraatrial thrombosis. It is predicted, therefore, that surgical results can be improved still further when account is taken of this vascular anatomy of the heart itself.

Intracardiac repair of lesions associated with atrioventricular discordance.

Discordant atrioventricular (AV) connection is a rare congenital cardiac anomaly. Associated cardiac defects modify the physiology, clinical presentation, and surgical management of these patients. We have reviewed our overall experience with 90 patients operated for lesions associated with AV discordance between 1975-1990. 90 patients, consecutively operated between 1975-1990, were reviewed. Patients' charts, angiograms and echocardiograms were studied. Follow-up was obtained from our records or was requested from referring cardiologists/paediatricians. It was completed in December 1992. For the analysis of risk factors of early death we used P values by chi-squared and Fisher's exact test. For the analysis of the triangulated events, we used the Kaplan-Meier method. Variables associated with P value over 0.20 were eliminated. 90 patients aged 6 months-30 years (mean 9.1 year) underwent repair of cardiac anomalies associated with AV discordance. Three patients had total cavopulmonary connection; the remainder received biventricular repair. Most important associated malformations were ventricular septal defect (77), subpulmonary obstruction (68) and tricuspid valve anomaly (21). 59 patients received extracardiac valved conduit, 10 had tricuspid valve replacement. Thirteen patients died in hospital (14%). One year and 10 year actuarial survival rate was 84% and 70% respectively. The most significant factors for early death were: anatomically abnormal tricuspid valve (P < 0.0001), tricuspid valve regurgitation (P < 0.002), date of operation (P < 0.012), preoperative or perioperative complete heart block (P < 0.015), and tricuspid valve surgery (P < 0.05). Complete heart block developed in 17 (20%) out of 85 patients who did not have it preoperatively. During the follow-up, 22 intracardiac reoperations were necessary (4 died). 63 patients of 73 survivors (86%) remain in NYHA Class 1, 6 in Class 2 and 4 in Class 3. The operative mortality was 14%. Twenty per cent of patients developed complete heart block. These results improved in the later part of the series (1985-1990); mortality decreased to 5% and incidence of heart block to 14%. Cardiac anomalies associated with AV discordance still present a surgical challenge. The data reported in our study should serve as a useful baseline for evaluation of newer surgical techniques, such as the "double switch" operation.