Hearts with isomerism of the right atrial appendages - one of the worst forms of disease in 2005

Atrioventricular Discordance with Double-Outlet Right Ventricle in Mirror Imagery and Levocardia: A Very Rare Case Report

A newborn without prenatal diagnosis, with bronchial and abdominal situs inversus in levocardia, was referred to our hospital for accurate evaluation; echocardiography showed venoatrial connections in mirror-image arrangement, atrioventricular (AV) discordance, and double-outlet right ventricle (DORV). Additional cardiac malformations were double upper caval district, atrial communication, subpulmonary interventricular communication, and moderate subvalvular and valvular pulmonary stenosis. Few days after birth, the patient presented low oxygen saturation and the heart team decided for a palliative surgery. We describe a very rare case in a newborn with bronchial-abdominal mirror imagery, AV discordance, and DORV in levocardia.

Identification of novel candidate genes in heterotaxy syndrome patients with congenital heart diseases by whole exome sequencing

Heterotaxy syndrome (HS) involves dysfunction of multiple systems resulting from abnormal left-right (LR) body patterning. Most HS patients present with complex congenital heart diseases (CHD), the disability and mortality of HS patients are extremely high. HS has great heterogeneity in phenotypes and genotypes, which have rendered gene discovery challenging. The aim of this study was to identify novel genes that underlie pathogenesis of HS patients with CHD. Whole exome sequencing was performed in 25 unrelated HS cases and 100 healthy controls; 19 nonsynonymous variants in 6 novel candidate genes (FLNA, ITGA1, PCNT, KIF7, GLI1, KMT2D) were identified. The functions of candidate genes were further analyzed in zebrafish model by CRISPR/Cas9 technique. Genome-editing was successfully introduced into the gene loci of flna, kmt2d and kif7, but the phenotypes were heterogenous. Disruption of each gene disturbed normal cardiac looping while kif7 knockout had a more prominent effect on liver budding and pitx2 expression. Our results revealed three potential HS pathogenic genes with probably different molecular mechanisms.

Role of fetal echocardiography in morphologic and functional assessment of fetal heart in diabetic mothers

Background

Diabetes mellitus (DM) is the commonest medical disorder faced during pregnancy and it includes type I, type II, and gestational diabetes. It may predispose to various complications including fetus malformation, macrosomia, spontaneous abortion, stillbirth, neonatal death, and intrauterine growth retardation. Hypertrophic cardiomyopathy (HCM) is one of the common anomalies depicted with diabetes. Fetal cardiac function analysis might provide important information on the hemodynamic status and cardiac adaptation to different perinatal complications.

Results

The mean septal thickness in the diabetic group was 0.7163 ± 0.1746 cm and 0.4989 ± 0.08068 cm in the control group. The mean myocardial thickness of the right ventricular free wall in the diabetic group was 0.6532 ± 0.13792 cm and 0.4874 ± 0.07482 cm in the control group. The mean myocardial thickness of the left ventricular free wall in the diabetic group was 0.6437 ± 0.13421 cm and 0.4737 ± 0.07573 cm in the control group. The mean value of myocardial performance index (Tie Index) in the diabetic group was 0.6232 ± 0.15606 and 0.4626 ± 0.04357 in the control group.

Conclusion

From our study, we can conclude that prenatal complete echocardiographic study should be mandatory in fetuses of diabetic mothers due to high risk of congenital heart defects and onset of hypertrophic cardiomyopathy with fetal cardiac function impairment in the third trimester.

Early diagnosis of congenital heart defects as well as evidence of hypertrophic cardiomyopathy and fetal cardiac function impairment that occurs in fetuses of maternal diabetes will definitely guide prompt postnatal therapy and care for those neonates.

Survival and Associated Risk Factors for Mortality Among Infants with Critical Congenital Heart Disease in a Developing Country

Critical congenital heart disease (CCHD) is associated with significant morbidity and mortality. However, data on survival of CCHD and the risk factors associated with its mortality are limited. This study examined CCHD survival and the risk factors for CCHD mortality. Using a retrospective cohort study of infants born with CCHD from 2006 to 2015, survival over 10 years was estimated using Kaplan-Meier analysis, and the risk factors for mortality were analyzed using multivariate Cox proportional hazards regression. A total of 491 CCHD cases were included in the study, with an overall mortality rate of 34.8% (95% confidence interval [CI] 30.6-39.2). The intervention/surgical mortality rate was 9.8% ≤ 30 days and 11.5% > 30 days after surgery, and 17% died before surgery or intervention. The median age at death was 2.7 months [first quartile: 1 month, third quartile: 7.3 months]. The CCHD survival rate was 90.4% (95% CI 89-91.8%) at 1 month, 69.3% (95% CI 67.2-71.4%) at 1 year, 63.4% (95% CI 61.1-65.7%) at 5 years, and 61.4% (95% CI 58.9-63.9%) at 10 years. Weight of < 2 kg at diagnosis, associated syndromes, poor pre-operative condition, and non-duct-dependent CCHD were independent risk factors for poor survival, with hazard ratios of 2.61, 2.10, 2.22, and 1.70, respectively. CCHD is associated with a high mortality rate. Low weight, poor pre-operative condition, associated syndromes, and non-duct-dependent CCHD are significant risk factors affecting the survival of infants with CCHD.

Prenatal Findings in Left Atrial Isomerism and an Overview of Heterotaxy Syndrome

Heterotaxy syndrome is a rare, complex disorder involving structural cardiac defects in combination with symmetrical development of abdominal viscera that are normally asymmetrical organs. The vast assortment of cardiac manifestations with accompanying abdominal visceral variations determines the prognosis of heterotaxy syndrome. This case study provides an example of the management of this disease, which is unique to the patient. This is a case report of heterotaxy syndrome diagnosed in utero at 29 weeks and 4 days.

Is an Appreciation of Isomerism the Key to Unlocking the Mysteries of the Cardiac Findings in Heterotaxy?

Pediatric cardiologists treating patients with severe congenital cardiac defects define “visceral heterotaxy” on the basis of isomerism of the atrial appendages. The isomeric features represent an obvious manifestation of disruption of left-right asymmetry during embryonic development. Thus, there are two subsets of individuals within the overall syndrome, with features of either right or left isomerism. Within the heart, it is only the atrial appendages that are truly isomeric. The remainder of the cardiac components shows variable morphology, as does the arrangement of the remaining body organs. Order is provided in this potentially chaotic arrangement simply by describing the specific features of each of the systems. These features as defined by clinicians, however, seem less well recognized by those investigating the developmental origins of the disruption of symmetry. Developmental biologists place much greater emphasis on ventricular looping. Although the direction of the loop can certainly be interpreted as representing an example of asymmetry, it is not comparable to the isomeric features that underscore the clinical syndromes. This is because, thus far, there is no evidence of ventricular isomerism, with the ventricles distinguished one from the other on the basis of their disparate anatomical features. In similar fashion, some consider transposition to represent abnormal lateralization, but again, clinical diagnosis depends on recognition of the lateralized features. In this review, therefore, we discuss the key questions that currently underscore the mismatch in the approaches to “lateralization” as taken by clinicians and developmental biologists.

Noncompaction cardiomyopathy and heterotaxy syndrome

Left ventricular noncompaction cardiomyopathy (LVNC) is characterized by compact and trabecular layers of the left ventricular myocardium. This cardiomyopathy may occur with congenital heart disease (CHD). Single cases document co-occurrence of LVNC and heterotaxy, but no data exist regarding the prevalence of this association. This study sought to determine whether a non-random association of LVNC and heterotaxy exists by evaluating the prevalence of LVNC in patients with heterotaxy. In a retrospective review of the Indiana Network for Patient Care, we identified 172 patients with heterotaxy (69 male, 103 female). Echocardiography and cardiac magnetic resonance imaging results were independently reviewed by two cardiologists to ensure reproducibility of LVNC. A total of 13/172 (7.5%) patients met imaging criteria for LVNC. The CHD identified in this subgroup included atrioventricular septal defects [11], dextrocardia [10], systemic and pulmonary venous return abnormalities [7], and transposition of the great arteries [5]. From this subgroup, 61% (n = 8) of the patients developed arrhythmias; and 61% (n = 8) required medical management for chronic heart failure. This study indicates that LVNC has increased prevalence among patients with heterotaxy when compared to the general population (0.014-1.3%) suggesting possible common genetic mechanisms. Interestingly, mice with a loss of function of Scrib or Vangl2 genes showed abnormal compaction of the ventricles, anomalies in cardiac looping, and septation defects in previous studies. Recognition of the association between LVNC and heterotaxy is important for various reasons. First, the increased risk of arrhythmias demonstrated in our population. Secondly, theoretical risk of thromboembolic events remains in any LVNC population. Finally, many patients with heterotaxy undergo cardiac surgery (corrective and palliative) and when this is associated with LVNC, patients should be presumed to incur a higher peri-operative morbidity based on previous studies. Further research will continue to determine long-term and to corroborate genetic pathways.

Isomerism in the setting of the so-called "heterotaxy": The usefulness of computed tomographic analysis

The most complex combinations of congenital cardiac malformations are found in the setting of bodily isomerism. The question remains, however, as to whether evidence of cardiac isomerism is always to be found in the setting of bodily isomerism, also known as "heterotaxy." We have previously shown that, when assessed on the basis of the extent of the pectinate muscles relative to the atrioventricular junctions, there is always isomerism of the atrial appendages in this setting. Doubt has been remained, however, as to whether these cardiac features can accurately be recognized during life. We have now encountered two patients showing features of the left and right bodily isomerism. Examinations of these patients made using computed tomography show that all features of isomerism, no matter how complex, can now be visualized during life. The images currently presented show, furthermore, that the features of the so-called "heterotaxy" can be seen during life, not only within the heart but also in all the thoracic and abdominal organs, albeit that the isomeric features are confined to the thoracic organs. Based on the images presented, we argue that if each system of organs is analyzed and described in independent fashion; then it is possible for clinicians to exclude any suggestion of ambiguity and to provide accurate descriptions of the overall arrangement. We further discuss the appropriate terminology to describe the entity we prefer to call isomerism, along with the indications and usefulness of computed tomography in revealing the anatomic features of the congenitally malformed heart.

Predictors of poor outcome among children with heterotaxy syndrome: a retrospective review

Objective

To determine predictors of poor outcome in patients with heterotaxy syndrome.

Methods

A retrospective review of children with heterotaxy syndrome, in a single tertiary paediatric cardiology centre, was conducted between 1 January 1997 and 1 January 2014 to determine predictors of poor outcome. Poor outcome was defined as death, cardiac transplantation or New York Heart Association (NYHA) functional class III or IV.

Results

There were 35 patients diagnosed with heterotaxy syndrome, 17 of whom were diagnosed antenatally. 22 patients had right atrial isomerism and 13 had left atrial isomerism. The median age of postnatal diagnosis was 2.5 days old (1 day to 19 months). 12 patients had a poor outcome; 6 patients died, 1 underwent cardiac transplantation and 5 had an NYHA functional class of >III. 5 patients had a biventricular repair and the remaining 30 had a univentricular repair. Type of atrial isomerism, univentricular or biventricular anatomy, severity of atrioventricular valve regurgitation or ventricular dysfunction, obstructed pulmonary venous return, occurrence of arrhythmia and presence of pulmonary atresia did not predict poor outcome. Fetal diagnosis also did not confer a survival advantage. The median duration of follow-up in this cohort was 65 months (2 days to 16.8 years).

Conclusions

Survival for patients with heterotaxy syndrome was 83% over a median follow-up of 65 months. 34% of patients had a poor outcome. None of the variables studied were predictive of death, transplantation or NYHA classification III or IV.

Right atrial isomerism in children older than 3 years

Background

There is a high mortality in infants with right atrial isomerism (RAI). However, less is known about outcome in older children with RAI. This study sought to evaluate those patients with RAI who survived older than 3 years of age without surgical intervention.

Results

A total of 33 consecutive patients (20 males) were enrolled in the study, mean age 6 years (range 3–32). None of the patients had surgical intervention for the RAI before age 3. Cardiac abnormalities include altered cardiac position (39 %), atrioventricular valve anomaly (87 %), single or functional single ventricle (55 %), pulmonary/subpulmonary obstruction (97 %), abnormal origin of the aorta (100 %), bilateral superior vena cava (67 %), and anomalous pulmonary venous drainage (66 %). Surgical intervention was performed after 3 years of age in 20 patients (61 %). None of them planned or had biventricular repair performed. 10 patients underwent the total cavopulmonary connection procedure, including four (40 %) who had atrioventricular valve (AVV) repair at the same time [all with common atrioventricular valve (CAVV)]. One patient died the day after the operation. A total of 69 % of patients with a CAVV had moderate or severe regurgitation, while 27 % with a single atrioventricular valve had moderate or severe regurgitation.

Conclusion

Patients with RAI who have survived to early childhood without surgical intervention have complex cardiac abnormalities. Survival after single stage total cavopulmonary connection is good but AVV repair is common.

Heterotaxy Syndrome: Proceedings From the 10th International PCICS Meeting

A session dedicated to heterotaxy syndrome was included in the program of the Tenth International Conference of the Pediatric Cardiac Intensive Care Society in Miami, Florida in December 2014. An invited panel of experts reviewed the anatomic considerations, surgical considerations, noncardiac issues, and long-term outcomes in this challenging group of patients. The presentations, summarized in this article, reflect the current approach to this complex multiorgan syndrome and highlight future areas of clinical interest and research.

CHD associated with syndromic diagnoses: peri-operative risk factors and early outcomes

CHD is frequently associated with a genetic syndrome. These syndromes often present specific cardiovascular and non-cardiovascular co-morbidities that confer significant peri-operative risks affecting multiple organ systems. Although surgical outcomes have improved over time, these co-morbidities continue to contribute substantially to poor peri-operative mortality and morbidity outcomes. Peri-operative morbidity may have long-standing ramifications on neurodevelopment and overall health. Recognising the cardiovascular and non-cardiovascular risks associated with specific syndromic diagnoses will facilitate expectant management, early detection of clinical problems, and improved outcomes--for example, the development of syndrome-based protocols for peri-operative evaluation and prophylactic actions may improve outcomes for the more frequently encountered syndromes such as 22q11 deletion syndrome.

Perinatal and infant outcomes of prenatal diagnosis of heterotaxy syndrome (asplenia and polysplenia)

Patients with heterotaxy syndrome (HS) have a range of anomalies and outcomes. There are limited data on perinatal outcomes after prenatal diagnosis. To determine the factors influencing perinatal and infant outcomes, we analyzed prenatal and postnatal variables in fetuses with HS from 1995 to 2011. Of 154 fetuses with HS, 61 (40%) had asplenia syndrome (ASP) and 93 (60%) had polysplenia syndrome (PSP). In the ASP group, 22 (36%) patients were elected for termination of pregnancy, 4 (10%) had fetal death, and 35 of 39 (90%) continued pregnancies were live born. In the PSP group, 12 (13%) patients were elected for termination of pregnancy, 5 (6%) had fetal death (4 with bradyarrhythmia), and 76 of 81 (94%) continued pregnancies were live born. Bradyarrhythmia was the only predictor of fetal death. In the live-born ASP group, 43% (15 of 35) died, 7 because of pulmonary vein stenosis, 4 postoperatively, and 4 because of noncardiac causes. In the live-born PSP group, 13% (10 of 76) died, 5 postoperatively, 2 from bradyarrhythmia, 1 from a cardiac event, and 2 from noncardiac causes. Pulmonary vein stenosis and noncardiac anomalies were independent risk factors for postnatal death. Only 8% of ASP patients achieved biventricular circulation, compared with 65% of PSP patients. In the live-born cohort, the 5-year survival rate was 53% for ASP and 86% for PSP. In conclusion, most PSP patients are currently alive with biventricular circulation in contrast with few ASP patients. Bradyarrhythmia was the only predictor of fetal death. Pulmonary vein stenosis and noncardiac anomalies were predictors of postnatal death.

Spectrum and outcome of primary cardiomyopathies diagnosed during fetal life

OBJECTIVES

The purpose of this study was to determine the phenotypic presentation, causes, and outcome of fetal cardiomyopathy (CM) and to identify early predictors of outcome.

BACKGROUND

Although prenatal diagnosis is possible, there is a paucity of information about fetal CM.

METHODS

This was a retrospective review of 61 consecutive fetal cases with a diagnosis of CM at a single center between 2000 and 2012.

RESULTS

Nonhypertrophic CM (NHCM) was diagnosed in 40 and hypertrophic CM (HCM) in 21 fetuses at 24.7 ± 5.7 gestational weeks. Etiologies included familial (13%), inflammatory (15%), and genetic-metabolic (28%) disorders, whereas 44% were idiopathic. The pregnancy was terminated in 13 of 61 cases (21%). Transplantation-free survival from diagnosis to 1 month and 1 year of life for actively managed patients was better in those with NHCM (n = 31; 58% and 58%, respectively) compared with those with HCM (n = 17; 35% and 18%, respectively; hazard ratio [HR]: 0.44; 95% confidence interval [CI]: 0.12 to 0.72; p = 0.007). Baseline echocardiographic variables associated with mortality in actively managed patients included ventricular septal thickness (HR: 1.21 per z-score increment; 95% CI: 1.07 to 1.36; p = 0.002), cardiothoracic area ratio (HR: 1.06 per percent increment; 95% CI: 1.02 to 1.10; p = 0.006), ≥3 abnormal diastolic Doppler flow indexes (HR: 1.44; 95% CI: 1.07 to 1.95; p = 0.02), gestational age at CM diagnosis (HR: 0.91 per week increment; 95% CI: 0.83 to 0.99; p = 0.03), and, for fetuses in sinus rhythm, a lower cardiovascular profile score (HR: 1.45 per point decrease; 95% CI: 1.16 to 1.79; p = 0.001).

CONCLUSIONS

Fetal CM originates from a broad spectrum of etiologies and is associated with substantial mortality. Early echocardiographic findings appear useful in predicting adverse perinatal outcomes.

Defects in laterality with emphasis on heterotaxy syndromes with asplenia and polysplenia: an autopsy case series at a single institution

Heterotaxy is a rare disease with high morbidity and mortality. Controversy exists over how to classify these syndromes with most cases stratified into asplenia/polysplenia syndromes or right/left isomerism. In an effort to review comprehensively specific pheonotypes associated with heterotaxy syndromes, we reviewed published cases series, adopted a classification scheme based on spleen status, and evaluated autopsy cases retrospectively with abnormal laterality at our institution. We categorized 116 cases as situs inversus totalis, polysplenia, asplenia, and single right-sided spleen. Cardiovascular abnormalities occurred in 87.1% of polysplenia, 90.5% of asplenia, and all cases of single right-sided spleen. For polysplenia, 48.9% had bilateral bilobed lungs, 87% had right-sided stomach, 58.1% had midline symmetric liver, and 60.4% had malrotated intestines. For asplenia, 51.9% had bilateral trilobed lungs, 86.7% had right-sided stomach, 45.8% had symmetric liver, and 65.5% had malrotated intestines. Atrioventricular septal defects occurred in 91.2% of asplenia compared to 56.8% of polysplenia cases. Eight percent had pulmonary/aortic stenosis or atresia. Double outlet right ventricle was more common in polysplenia (32.6%) compared to asplenia (21.4%). Total anomalous systemic venous return was described in 55.6% of polysplenia and total anomalous pulmonary venous connections in 81% of asplenia cases. Greater than half of the cases had no heterotaxy diagnosis. Although, we found similar heterotaxy-associated characteristics, the frequencies differed from previous studies. We found great variation in how heterotaxy-associated defects were described, diagnosed, and reported. Although there are known associated characteristics with the polysplenia/asplenia syndromes, correct identification requires a standardized approach for diagnosis and reporting.

Prenatal diagnosis of atrial isomerism in the Korean population

OBJECTIVE

To report our experiences in the prenatal diagnosis of atrial isomerism and postnatal outcomes.

METHODS

A total of 80 fetuses prenatally diagnosed with atrial isomerism were retrospectively analyzed between 1999 and 2011 at a single institution.

RESULTS

Of 43 fetuses with prenatally diagnosed right atrial isomerism (RAI), 40 cases were analyzed. The diagnostic accuracy was 93%. The main intracardiac anomalies in RAI were atrioventricular septal defect (AVSD), abnormal pulmonary venous connection, bilateral superior vena cava (BSVC), and pulmonary atresia. Among 28 live births, three infants were lost to follow up, and the overall survival rate was 60%. Of 37 fetuses with prenatally diagnosed left atrial isomerism (LAI), 35 were evaluated. The diagnostic accuracy was 97%. The main intracardiac anomalies in LAI were ventricular septal defect, BSVC, AVSD, double outlet right ventricle, and bradyarrhythmia. Among seven patients with bradyarrhythmia, only one showed a complete atrioventricular block. All fetuses had an interrupted inferior vena cava with azygous continuation. The overall survival rate was 90%.

CONCLUSION

Our study confirms the previous findings of fetal atrial isomerism. We also demonstrates a much lower prevalence of AVSD and complete heart block in LAI and a better survival rate in RAI. Although the postnatal outcomes for RAI were worse than those for LAI, successful postnatal surgery with active management improved the survival rate.

Magnetic navigation in adults with atrial isomerism (heterotaxy syndrome) and supraventricular arrhythmias

AIMS

We analysed the type and mechanism of supraventricular arrhythmias encountered in a series of symptomatic adults with atrial isomerism undergoing catheter ablation procedures.

METHODS AND RESULTS

The study population included consecutive adults with atrial isomerism who had previously undergone surgical repair or palliation of the associated anomalies. Patients underwent electrophysiological study for symptomatic arrhythmia in our institution between 2010 and 2012 using magnetic navigation in conjunction with CARTO RMT and three-dimensional (3D) image integration. Eight patients (five females) with a median age of 33 years [interquartile range (IQR) 24-39] were studied. Access to the cardiac chambers of interest was obtained retrogradely via the aorta using remotely navigated magnetic catheters in six patients. Radiofrequency ablation successfully targeted twin atrioventricular (AV) nodal reentrant tachycardia in two patients, atrial fibrillation (AF) in three, focal atrial tachycardia (AT) mainly originating in the left-sided atrium in four patients, and macro-reentrant AT dependent on a right-sided inferior isthmus in three patients. The median fluoroscopy time was 3.0 min (IQR 2-11). After a median follow-up of 10 months (IQR 6-21), five of the ablated patients are free from arrhythmia; two patients experienced episodes of self-terminated AF and AT, respectively, within one month post-ablation; the remaining patient had only non-sustained AT during the electrophysiological study and was managed medically.

CONCLUSION

Various supraventricular tachycardia mechanisms are possible in adults with heterotaxy syndrome, all potentially amenable to radiofrequency ablation. The use of remote magnetic navigation along with 3D mapping facilitated the procedures and resulted in a short radiation time.

The outcome of patients with right atrial isomerism is poor

Right-atrial isomerism (RAI) is a heterotaxy syndrome with disturbances of left-right axis development resulting in complex heart malformations and anomalies of the thoracic and abdominal organs. To study the outcome of RAI, all data from patients diagnosed with this syndrome at Helsinki University Hospital between January 1976 and December of 2010 were reviewed. The outcomes were studied for 32 patients (38 % girls). The overall survival was 22 % at a median follow-up time of 13.8 years (range 0.1-33). Extracardiac malformations, mostly asplenic, occurred in 91 % of patients. Cardiac defects included dextrocardia in 44 % and common atrioventricular valve in 100 % of patients. Ventriculoarterial discordance or double-outlet ventricle was seen in 56 and 44 % of patients, respectively. Total anomalous pulmonary venous drainage occurred in 75 % and partially anomalous venous drainage in 13 % of patients. Pulmonary outflow-tract obstruction was identified in 91 % of patients. Cardiac arrhythmias were noted in nine patients (28 %), two of them with atrioventricular block. Cardiovascular surgery was performed in 71 % patients (N = 25), seven patients were inoperable. Biventricular repair was not possible in any of the patients. During long-term follow-up there was no significant difference between the patients with total, normal, or partially anomalous pulmonary venous drainage (P = 0.5). In conclusion, RAI is one of the most severe forms of congenital cardiac diseases. The prognosis remains poor despite modern surgical techniques. When RAI is identified during pregnancy, prenatal counseling, termination, or planning for prompt cardiac treatment after the birth is necessary.

Atrioventricular valve repair for patient with heterotaxy syndrome and a functional single ventricle

Heterotaxy syndrome is a mortality risk factor for patients with complex heart disease. These patients often have common atrioventricular valve (CAVV) morphology and significant atrioventricular valve regurgitation - yet another mortality risk factor in congenital heart disease. Thus, patients with both heterotaxy syndrome and atrioventricular valve regurgitation are at highest risk of mortality. A large number of patients with heterotaxy syndrome have CAVV and a functional single ventricle. These patients are more difficult to operate than patients with biventricular morphology because in the former, the CAVV is often less adapted to systemic afterload than the mitral valve. Herein, we present the results of atrioventricular valve repair surgeries performed at the Okayama University Hospital on patients with heterotaxy syndrome, atrial isomerism, and a functional single ventricle. In addition, we review the current literature in this typically challenging patient population. In-depth understanding of reasonable management strategies and resolution of technical issues will help guide surgeons during this procedure.

Improving outcomes of the surgical management of right atrial isomerism

BACKGROUND

Patients with right atrial isomerism (RAI) have several cardiac malformations historically resulting in significant morbidity and mortality. We sought to assess whether current surgical strategies have improved the outcomes of patients with RAI.

METHODS

A retrospective review of our database from 1997 to 2010 identified 60 consecutive patients with RAI who underwent initial palliation at Mt. Fuji Shizuoka Children's Hospital. All of the patients had a functional single ventricle. Of the 60 patients, 33 patients (51.7%) had obstructed total anomalous pulmonary venous drainage (TAPVD), 23 patients (40.3%) had significant (more than moderate) atrioventricular valvular regurgitation (AVVR), 7 patients (12.3%) had hiatus hernia, and 4 patients (6.7%) had major aortopulmonary collateral arteries. Pulmonary outflow atresia was present in 39 of the patients (65%), and 46 patients had systemic-to-pulmonary artery shunts. Of the 33 patients with TAPVD, 18 underwent repair of the condition at initial palliation, 9 others at the time of a Glenn operation, 2 more through a Fontan operation, and 4 at the interstage between palliative surgeries. Eight of the 23 patients with significant AVVR underwent atrioventricular valve repair at initial palliation, 8 others at the time of Glenn operation, 4 others at the time of Fontan operation, and 3 during the interstage between operations. An initial neonatal surgical procedure was performed in 30 patients (50%). The mean follow-up period for patients in the study was 53.1 months.

RESULTS

Operative mortality after initial palliation was 15.4% (4 of 26 patients) before 2003 and 17.6% (6 of 34 patients) after 2004 (p=NS). Five-year survival was 53.8% before 2003 and 81.7% after 2004 (p=0.035, log-rank test). A multivariate analysis identified persistent AVVR of more than moderate degree (p=0.04) as a factor associated with late mortality.

CONCLUSIONS

The outcomes of surgery for RAI are improving. Neonatal palliative surgery for RAI carries a high operative risk of early mortality, and persistent significant AVVR remains a risk factor for late mortality.

Right Atrial Isomerism – Preponderance in Asian Fetuses. Using the Stomach-distance ratio as a Possible Diagnostic Tool for Prediction of Right Atrial Isomerism

Introduction: To present the characteristics and spectrum of associated anomalies in right- and left-sided isomerism in our local population and to assess the possibility of using stomach-distance ratio (SDR) of less than 0.34 as a diagnostic tool to predict right atrial isomerism. Materials and Methods: This was a retrospective study of fetuses in our department over a period of 8 years with postnatally confirmed prenatal diagnosis of atrial isomerism. Results: In 22 cases, atrial isomerism was confirmed by post-mortem or postnatal echocardiography. Eighteen (81.8%) fetuses had right isomerism. Their main abnormal ultrasound findings were pulmonary stenosis or atresia (n = 9), atrioventricular septal defect (n = 10), right-sided stomach (n = 9), transposition of great arteries (n = 6), dextrocardia (n = 8), single ventricle (n = 4), juxtaposition of inferior vena cava and descending aorta (n = 5), ventricular septal defect (n = 2), interrupted inferior vena cava with azygous drainage (n = 2) and double outlet right ventricle (n = 3). Four (18.2%) fetuses had left isomerism. Their abnormal ultrasound findings were dextrocardia (n = 3), right-sided stomach (n = 3), atrioventricular septal defect (n = 2), double outlet ventricle (n = 2), ventricular septal defect (n = 1), pulmonary stenosis (n = 2) and interrupted inferior vena cava with azygous drainage (n = 1). 66.7% (12/18) of cases with right isomerism had SDR of less than 0.34 compared to 0% (0/4) of the cases with left isomerism (P = 0.02). Conclusion: Our study suggests an Asian predilection towards right isomerism compared to Western populations. We postulate that there may be racial differences in the expression of these 2 forms of isomerism. The ultrasound findings of complex heart disease and abnormal arrangement of great vessels in abdominal cavity, though important, are varied and non-specific evidence for either form of fetal atrial isomerism. There is a possibility of using the SDR <0.34 (representing stomach proximity to the fetal spine) as a possible diagnostic tool to predict right-sided atrial isomerism. Key words: Azygous vein, Cardiac defects, Dextrocardia, Heterotaxy syndrome, Stomach localisation, Stomach near spine, Visceral heterotaxy

Long-term outcome of twin atrioventricular node and supraventricular tachycardia in patients with right isomerism of the atrial appendage

BACKGROUND

Twin AV nodes and resulting supraventricular tachycardia (SVT) have been described in right atrial isomerism (RAI).

OBJECTIVE

We sought to analyze the long-term outcome of patients with RAI with a focus on rhythm disturbances.

METHODS

Retrospective study of 257 patients (152 male and 105 female, 1,171 patient-years) with RAI diagnosed between 1980 and 2005.

RESULTS

SVT in 68 patients (26%) occurred at various ages from the prenatal period to 15 years and was only significantly associated with balanced ventricles (P = .009). Cardioversion was achieved in by verapamil in 6 of 6 cases (100%), adenosine in 18 of 21 cases (88%) and propranolol in 10 of 12 cases (83%). Electrocardiographic evidence of twin AV nodes, as shown by 2 discrete non-pre-excited QRS complexes, was found in 28 of 44 (64%) patients with more than 2 electrocardiograms, and was more frequent in those with balanced ventricles rather than a dominant ventricle and would increase risk of SVT. Recurrence of SVT was documented in 27 (40%) patients 1 day to 4.5 years after the first episode. However, the occurrence or recurrence of SVT was not associated with increased all-cause or surgical mortality or sudden death. Successful catheter ablation of ventriculoatrial pathways with junctional ectopic tachycardia at radiofrequency energy delivery was obtained in 5 of 6 patients.

CONCLUSION

This study showed that twin AV nodes in RAI patients could be disclosed by serial electrocardiograms and that SVT, most likely a twin node tachycardia, was common and tended to recur but could be managed by ablation or medication.

Hepatic necrosis following repair of totally anomalous pulmonary venous connection

We report a case of an infant with asplenia syndrome, isomerism of the right atrial appendages, and totally anomalous pulmonary venous connection who experienced hepatic failure following surgical correction of the anomalous pulmonary venous connection. We describe associated anomalies of the portal venous system.

Clinical investigations over 13 years to establish the nature of the cardiac defects in patients having abnormalities of lateralization

INTRODUCTION

The first step in diagnosing congenital cardiac malformations is to assess the arrangement of the atrial appendages. In patients with abnormal lateralization of the organs of the body, the arrangement of atrial appendages is neither normal, nor a mirror image of normal. There are 2 categories of abnormal arrangement based on the morphology of the atrial appendices, namely right isomerism and left isomerism, and in almost all instances these are found in the setting of so-called heterotaxy syndromes.

OBJECTIVE

To evaluate the various congenital cardiac malformations those are associated with abnormalities of lateralization, and to discuss the diagnostic tools, therapeutic options, and outcome for these patients.

PATIENTS AND METHODS

We studied 134 patients, who had been admitted to our department of paediatric cardiology with known abnormalities of lateralization and congenital cardiac defects between 1990 and 2003. The data relating to each patient was evaluated retrospectively. The arrangement of the atrial appendages was established echocardiographically, and/or angiographically, and/or on the basis of morphologic investigations during the operation. These studies showed that 43 (32.1%) of the patients had right isomerism, and 88 (65.7%) had left isomerism. In 2 (1.5%), there was mirror-imaged arrangement, while in the final patient (0.07%), we were unable to determine sidedness with certainty. The median age at diagnosis was 0.66 years, and the females outnumbered the males in a ratio of 3 to 1. Patients in the 2 isomeric groups were compared with regard to age, cardiac defects, diagnostic tools and outcomes.

RESULTS

The difference in mean ages of the two groups of patients was statistically significant, those with right isomerism being 1.0 minus or plus 1.5 years, as opposed to those with left isomerism being 3.3 minus or plus 4.7 years (P is less than 0.005). Of the patients with right isomerism, 32 (74.4%) had left-sided, and 11 (25.6%) right-sided hearts, whereas in those with left isomerism, the hearts were left-sided in 65 (73.9%), and right-sided in 21 (23.9%), with 2 (2.2%) positioned in the midline. Extracardiac totally anomalous pulmonary venous connection was more common in those with right isomerism, being found in 13 patients (30.2%) as opposed to 5 patients (5.7%) with left isomerism. In only 8 of those with right isomerism did we find two perforate atrioventricular valves (18.6%), this arrangement being found in 34 (38.6%) of those with left isomerism. Pulmonary atresia and stenosis were present in 40 (93.0%) of those with right isomerism, but also in 41 (46.6%) of the patients with left isomerism. Angiographic and echocardiographic investigations were concordant in about three-quarters of patients with both right and left isomerism. All patients with extracardiac totally anomalous pulmonary venous connection died. Overall, 22 of the patients with right isomerism died (51.2%), as opposed to 20 (22.7%) of those with left isomerism.

CONCLUSION

Our experience confirms that patients with right isomerism have more complex cardiac defects than those with left isomerism. Overall, the presence of isomerism carries a poor prognosis, the more so for right isomerism, with this related to the complex cardiac abnormalities. In our cohort, extracardiac totally anomalous pulmonary venous connection with pulmonary arterial obstruction was always a fatal combination. The mapping of cardiac and abdominal morphologies is still essential for proper diagnosis of these syndromes, especially in fetal life.

A case of right isomerism showing long survival without surgery

We report an autopsy case of right isomerism in a 42-year-old Japanese man. Although he had not undergone any surgical intervention, he was healthy and did not exhibit any symptoms of heart failure. The cardiac findings indicated right isomerism with complex and severe cardiac malformations, including a morphologically common atrium, common atrioventricular valve, double inlet right ventricle, total anomalous pulmonary venous drainage, pulmonary outflow obstruction, pulmonary atresia, and major aortopulmonary collaterals from the descending aorta. He had no spleen, and exhibited some gastrointestinal malformations. The absence of risk factors for mortality from right isomerism, such as pulmonary venous obstruction, AV valve regurgitation, sepsis or severe arrhythmia, might have contributed to the longevity of this patient. The presence of pulmonary outflow obstruction that is reported to confer a better prognosis might also have contributed to his longevity.