Cardiac Rhythm Disturbances in Heterotaxy Syndrome

Prenatal diagnosis of fetal bradyarrhythmia and postnatal outcome

INTRODUCTION

Prenatal diagnosis of Fetal bradyarrhythmia leads to parental and care provider anxiety as data on outcome is scarce. We aimed to correlate the prenatal presentation of fetal bradyarrhythmia with postnatal outcome.

METHODS

Retrospective analysis of case records from 2017 to 2021. All fetuses with sustained bradyarrhythmia beyond 11 weeks were included in the study.

RESULTS

Twenty fetuses were identified: mean gestational age at diagnosis was 23 weeks 2 days. The type of bradyarrhythmia was as follows: Complete atrioventricular block 10 (50 %), Sinus Bradycardia 7 (35 %), second degree atrioventricular block 2 (10 %), and Unclassified 1 (5 %). In 10 fetuses, cardiac and extracardiac anatomy were normal; 8 fetuses (40 %) had cardiac anomalies,1 fetus had intraventricular hemorrhage and 1 had nuchal cystic hygroma. Among the fetuses with associated anomalies, there were 5 terminations of pregnancy (TOP), 1 intrauterine fetal demise (IUD), 3 neonatal demise (NND) and 1 livebirth. Among fetuses with normal anatomy, there were 2 TOP and 8 livebirths; five of the 10 mothers (50 %) tested positive for Anti Ro/La antibodies. All the 6 liveborn fetuses with complete atrioventricular block are on conservative management: 2 on metaproterenol and 4 on clinical follow up. Nine out of the 10 cases that had a postnatal paediatric cardiology assessment had a correct prenatal diagnosis.

CONCLUSION

Correct prenatal identification of fetal bradyarrhythmia is feasible in about 90 % of cases. The risk of postnatal pacemaker requirement appears to be low irrespective of maternal Anti Ro/La status.

Cardiac Laterality: Surgical Results of Right Atrial Isomerism

Right atrial isomerism (RAI) is a complex entity with varying diagnostic and treatment outcomes due to its rarity. Treatment options range from palliative to corrective surgeries, resulting in heterogeneous outcomes. The aim of this study was to analyze the results obtained after cardiac surgery in patients with RAI. A retrospective study was conducted, including patients diagnosed with RAI who underwent cardiac surgery. Their follow-up was from 1 January 2010 to 31 March 2020. Demographic characteristics and perioperative conditions were described. Thirty-eight patients were included, the median age was 4 years (IQR 2-9.2) and 57.9% were men. The main diagnoses were atrioventricular canal (63.2%) and pulmonary stenosis (55.3%). The most common surgical procedures were modified Blalock-Taussig shunt (65.8%) and total cavopulmonary connection with an extracardiac conduit fenestrated without cardiopulmonary bypass (15.9%). We did not find any factors associated with negative outcomes in these patients. The overall survival was 86.8%, with a better outcome in those who did not require reintubation (log rank, p < 0.01). The survival of RAI was similar to other centers. Individuals with RAI should be evaluated rigorously to determine an adequate repair strategy, considering high morbidity and mortality.

Clinical implications of airway anomalies and stenosis in patients with heterotaxy syndrome

In heterotaxy syndrome, bronchopulmonary situs usually reflects atrial situs, resulting in either right (RAI) or left atrial isomerism (LAI). This study determines airway anomalies and its implications in patients with heterotaxy. This retrospective study included 223 patients with heterotaxy syndrome who received an integrated cardiac computed tomography evaluation. Patient database from 1995 to 2020 was reviewed. The patients were examined by a congenital heart disease team comprising pediatric cardiologists, radiologists, pulmonologists, and cardiovascular surgeons. Among the 223 patients, 189 (84.8%, M/F  =  1.66) had RAI and 29 had LAI (13.0%, M/F  =  0.71). Five patients had indeterminate isomerism (2.2%, M/F  = 1.5). Discordant bronchopulmonary and atrial situs occurred in 4% patients, while discordant bronchopulmonary, atrial, and splenic situs occurred in 23.2% patients. Lower airway stenosis was observed in 61 patients (27.4%), including 27.5%, 20.7%, and 60% RAI, LAI, and indeterminate isomerism patients, respectively (p = 0.189). One patient had an intrinsic long segment lower tracheal stenosis and received slide tracheoplasty. Initial cardiac operation was performed in 213 patients. Higher surgical mortality occurred in patients with RAI (19.5% vs. none for LAI and indeterminate isomerism, p = 0.038). In patients with RAI, lower airway anomaly/stenosis increased the duration of ventilator usage (p = 0.030) but did not affect surgical mortality. Total anomalous pulmonary venous return to systemic veins and pulmonary venous stenosis were major surgical risk factors. Bronchopulmonary isomerism shares a similar isomeric pattern to cardiac atrial appendage. Lower airway anomalies/stenosis was common in patients with heterotaxy, resulting in prolonged ventilator therapy in patients with RAI.

Outcomes of Biventricular and Single Ventricle Heterotaxy Patients: A Single Center 5-Decade Experience

BACKGROUND

Surgical palliation of patients with heterotaxy syndrome has proven challenging. Long-term outcomes have historically been poor. Factors contributing to these outcomes are not completely understood.

METHODS

The institutional databases were queried for patients with heterotaxy syndrome from 1973-2021. Comparisons were made between patients managed with single ventricle (SV) and biventricular (BiV) physiology.

RESULTS

Heterotaxy syndrome was identified in 230 patients [polysplenia (47%), asplenia (53%)]. 199 patients had SV physiology, 180 (78%) had undergone Fontan palliation. 31 patients had BiV, including 20 (9%) with surgical intervention and 11 (5%) without surgical intervention. Median age at Fontan was 7.5 (IQR 8.8) years. Median follow-up was 20 (IQR 21) years. Kaplan Meier analysis showed decreased survival with SV physiology (SV 53±4% vs. BiV 93±5% at 30 years, p=0.001), as well as asplenia compared to polysplenia (49±5% vs. 68±5% at 30 years, p<0.001). Polysplenia patients with BiV demonstrated the best survival (100% of polysplenia BiV alive vs. 53±25% of asplenia BiV at 30 years, p<0.001). Overall 8 (3.5%) underwent cardiac transplantation at a median of 17 years of age. On multi-variable analysis, risk factors associated with mortality included SV physiology (OR 7.2, 95% CI 2.4-21.7), no prior Glenn (OR 3.6, 95% CI 1.9-6.7), need for permanent pacemaker (OR 2.3, 95% CI 1.2-4.6), and asplenia (OR 2.7, 95% CI 1.5-5.0).

CONCLUSIONS

Overall, patients with asplenia demonstrated decreased survival compared to those with polysplenia, and SV physiology had decreased survival compared to BiV. BiV physiology with polysplenia had the best survival.

Advances in the Prenatal Management of Fetal Cardiac Disease

Advances in the field have improved the prenatal management of cardiovascular diseases over the past few decades; however, there remains considerable challenges in the approach towards patient selection as well as the applicability of available therapies. This review aims to discuss the current knowledge, outcomes and challenges for prenatal intervention for congenital heart disease.

Congenital Abnormalities in the Infant of a Diabetic Mother

Diabetes mellitus is among the most common chronic diseases worldwide. Infants of diabetic mothers are at increased risk of having congenital abnormalities. Tremendous progress has been achieved in the pregnancy care of diabetic women; however, the risk of birth defects associated with maternal diabetes still exists. These anomalies might arise in many organs and systems of the developing fetus. Many mechanisms have been implicated in the teratogenicity of maternal diabetes and it is critical to achieve good glycemic control before conception in women with diabetes. Neonatal clinicians must be able to identify patients at risk and recognize the signs of diabetic embryopathy. This article presents a review of congenital anomalies associated with maternal diabetes.

Surgical management of hearts with isomeric atrial appendages

BACKGROUND AND AIM

On the basis of previously published accounts, coupled with our own experience, we have assessed the surgical approaches to patients with isomeric atrial appendages.

METHODS

We reviewed pertinent published studies on surgical treatment of individuals with isomeric atrial appendages, with the pertinent surgical details provided by most of the manuscripts.

RESULTS

Half of patients with right isomerism, and two-thirds of those with left isomerism have bilateral superior caval veins. Azygos extension of the inferior caval vein is reported in three-quarters of those with left isomerism. The coronary sinus is universally absent in right isomerism, along with totally anomalous pulmonary venous connection, and is absent in two-fifths of those with left isomerism. Univentricular atrioventricular connections are expected in up to three-quarters of those with right isomerism. Atrioventricular septal defect is reported in up to four-fifths, more frequently in right isomerism, with such patients typically having discordant ventriculoatrial connections or double outlet right ventricle. Reported mortalities extend to 85% for those with right, and 50% for those with left isomerism. In right isomerism, mortality is up to 54% for systemic-to-pulmonary arterial shunting, up to 75% for univentricular repair, and up to 95% for repair of totally anomalous pulmonary venous connection itself. No more than one-quarter had undergone Fontan completion, with reported mortalities of 21%.

CONCLUSION

Early surgical results are satisfactory in patients with left isomerism, but disappointing for those with right. Recent advances in cardiac and liver transplantation may offer improved survival.

A Rare Case of Recurrent Pneumonia in Heterotaxy Syndrome, Polysplenia/Left Isomerism

Heterotaxy syndrome (HS) or situs ambiguous refers to the abnormal arrangement of viscera across the body axis, and abnormalities arise depending on the isomerism of the right or left atrial appendage. The cause remains unexplained and is attributed to a combination of genetic mutations and environmental factors. It is a rare condition and may remain undiagnosed for a long time. In this report, we aim to highlight an unusual presentation and aggravation of an infection due to the underlying isomerism of the left atrial appendage. We discuss the case of a female patient who presented with symptoms of fever and cough. The patient underwent prolonged antibiotic treatment, and her recovery was slow. The presence of bilobed lungs, vertical left-bronchus, and polysplenia on CT scan explained the left-sided aspiration pneumonia. The hypofunctioning spleen (polysplenia) caused her to have a weak immunological response, necessitating prolonged antibiotic use. She was followed up over time and had a recurrence of pneumonia within a few months. The condition is associated with high morbidity and mortality, and the role of early diagnosis and reporting to prevent complications is paramount. The recurrent pneumonia observed in the patient also raises questions related to long-term antibiotic use and immunization in the case of polysplenia in this patient population.

The multisystem nature of isomerism: left isomerism complicated by Abernethy malformation and portopulmonary hypertension

Isomerism, also referred to as "heterotaxy" is a complex set of anatomic and functional perturbations. One of the most obvious manifestations of isomerism is the disturbance of organ arrangement, such that the thoracic organs are no longer asymmetric on the left and right. We report the case of a 14-year-old female in whom exercise-induced dyspnea led to a late diagnosis of left isomerism complicated by Abernethy malformation and portopulmonary hypertension. A comprehensive evaluation revealed two anatomic left lungs and hyparterial bronchi, bilateral left atria, an interrupted inferior caval vein with azygos continuation, multiple spleens, sinus node dysfunction, hepatic hypertrophy with focal nodular hyperplasia, and absence of the portal vein. Pulmonary vasodilator therapy was initiated resulting in clinical improvement. This case exhibits unique features including a late diagnosis of isomerism with Abernethy malformation and portopulmonary hypertension. The patient's presentation, medical workup, and future treatment emphasise the importance of multidisciplinary care in children with complex multisystem disease. We review the multiple cardiac and extracardiac manifestations of isomerism.

Twin atrioventricular nodes, arrhythmias, and survival in pediatric and adult patients with heterotaxy syndrome

BACKGROUND

Heterotaxy syndrome is likely to involve arrhythmias from associated conduction system abnormalities, which are distinct in different subtypes of isomerism and may change further after interventions and remodeling.

OBJECTIVE

The purpose of this study was to understand the risk of arrhythmias and its relation to isomerism subtypes.

METHODS

Patients diagnosed between 1980 and 2019 as having heterotaxy syndrome were enrolled and grouped as right atrial isomerism (RAI), left atrial isomerism (LAI), or indeterminate isomerism.

RESULTS

Of the 366 patients enrolled, 326 (89.1%) had RAI, 35 (9.6%) LAI, and 5 (1.4%) indeterminate isomerism; 71 (19.4%) patients were adults. Arrhythmias occurred in 37.2% of patients (109 supraventricular tachycardia [SVT], 8 atrial fibrillation/flutter, 12 ventricular tachycardia, and 14 paced bradycardia). Freedom from arrhythmias by the age of 1, 5, 10, 20, and 40 years was 0.849, 0.680, 0.550, 0.413, and 0.053, respectively. Twin atrioventricular nodes were identified in 51.5% of patients with RAI, 8.7% of patients with LAI, and 40.0% of patients with indeterminate isomerism and were the key predictors of SVT. Indeterminate isomerism was also a risk factor for SVT. Other forms of tachycardia appeared relatively late. Sinus bradycardia with junctional rhythm was common in LAI (48.7%) and less in indeterminate isomerism (20.0%), with none occurring in RAI. Only in patients with RAI who showed the poorest survival, ventricular tachycardia worsened the long-term survival.

CONCLUSION

RAI was the predominant subtype of heterotaxy in this cohort. Collectively, the median RAI/LAI ratio was 0.731 and 5.450 in Western and East Asian studies, respectively. Arrhythmias, tachycardia, or paced bradycardia were common, but the spectrum was distinct among subtypes.

Neonatal Assessment of Infants with Heterotaxy

Heterotaxy is a generalized term for patients who have an abnormality of laterality that cannot be described as situs inversus. Infants with heterotaxy can have significant anatomic and medical complexity and require personalized, specialized care, including comprehensive anatomic assessment. Common and rare anatomic findings are reviewed by system to help guide a thorough phenotypic evaluation. General care guidelines and considerations unique to this patient population are included. Future directions for this unique patient population, particularly in light of improved neonatal survival, are discussed.

Junctional ectopic tachycardia in infants and children

Tachyarrhythmias originating in the atrioventricular (AV) node and AV junction including the bundle of His complex (BH) are called junctional tachycardia (JT) or junctional ectopic tachycardia (JET). Congenital JET (CJET) is a rare arrhythmia that occurs in patients without a preceding cardiac surgery and can be refractory to medical therapy and associated with high morbidity and mortality. CJET has a high rate of morbidity and mortality with death occurring in 35% of cases. JET occurring within 72 hours after cardiac surgery is referred to as postoperative JET (POJET) and caused by direct trauma, ischemic, or stretch injury to the AV conduction tissues during surgical repair of congenital heart defects. Focal junctional tachycardia (FJT) is also known as automatic junctional tachycardia and includes paroxysmal or non-paroxysmal forms. We discuss a staged approach to therapy with improved pharmacological therapies and the use of catheter-based therapies.

Left atrial isomerism associated with aneurysmal enlargement of right atrial appendage: A case report with literature review

We present a prenatally diagnosed case of heterotaxy syndrome (HS) in which left atrial isomerism (LAI) was associated with an aneurysmal enlargement of the right atrial appendage (RAA). Although LAI is usually associated with complex cardiac and extracardiac anomalies, the association of LAI and right atrial appendage aneurysm (RAAA) is exceptional. Congenital RAAA itself is an idiopathic, very rare cardiac anomaly characterized by the enlargement of the appendage in the absence of any other cardiac or extra-cardiac defect. The prognosis of the heterotaxy is poor with associated major cardiac malformations and even cases with minor cardiac anomalies are at risk postnatally for complications like biliary atresia, intestinal rotational abnormalities, and immune disorders. In this case, the prenatal diagnosis of the isomerism was mainly based on the abnormalities of caval veins. Although no typical complex cardiac anomaly was present, the HS was associated with biliary atresia, polysplenia, and malrotation of the gut. Associated RAAA further imposed an additional risk of complications such as tachyarrhythmias, thromboembolic events, and aneurysmal rupture.