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

Early and long-term outcomes following cardiac surgery for patients with heterotaxy syndrome

Objective

Heterotaxy syndrome is a complex multisystem abnormality historically associated with high morbidity and mortality. We sought to evaluate the early and long-term outcomes after cardiac surgery in heterotaxy syndrome.

Methods

This is a single-center retrospective review of patients with heterotaxy syndrome undergoing single-ventricle palliation or primary or staged biventricular repair from 1998 to 2018. Patients were stratified by single ventricle versus biventricular physiology, and the severity of atrioventricular valve regurgitation. Demographics, anatomic characteristics, and early and late outcomes, including the length of stay, mortality, and surgical or catheter reinterventions, were analyzed.

Results

Among 250 patients, 150 (60%) underwent biventricular repair. In-hospital mortality was 7.6% (n = 19). Median follow-up was 5.2 (range, 0-16) years. Among survivors to discharge, mortality was 19% (n = 44) and reintervention was 52% (n = 120). Patients with moderate/severe atrioventricular valve regurgitation were older (32 vs 16 months, P = .02), were more likely to experience adverse events during their index surgical admission (72% vs 46%, P < .001), and had longer in-hospital length of stay (20 vs 12 days, P = .009). Among patients with moderate to severe atrioventricular valve regurgitation, single-ventricle palliation is associated with a greater risk of unplanned reintervention compared with patients undergoing biventricular repair (hazard ratio, 2.13; CI, 1.10-4.12; P = .025).

Conclusions

There was no significant difference in early or late outcomes in single-ventricle versus biventricular repair strategies in heterotaxy. In the subgroup of patients with moderate/severe atrioventricular valve regurgitation, patients who underwent single-ventricle palliation were 2.5 times more likely to need a late reintervention compared with those undergoing biventricular repair.

Atrial fibrillation in adult congenital heart disease and the general population

BACKGROUND

Atrial fibrillation (AF) in adult patients with congenital heart disease (ACHD) may appear early, depending on individual characteristics.

OBJECTIVES

The goals of this study were to investigate the epidemiological spectrum of AF in the entire cohort of ACHD and compare it with that in the general population.

METHODS

A retrospective study was performed in the nationwide cohort 2000-2014 with AF onset during 2003-2014.

RESULTS

In the cohort of ACHD, 2350 patients had AF; the incidence increased with age, plateauing around age 70. In patients aged 25-29, 45-49, 65-69, 75-79, and ≥80 years, the annual incidence was 1.3, 7.9, 20.6, 23.7, and 21.4/1000 per year, respectively. In the general population without CHD, 347,979 patients had AF; the annual incidence was <1/1000 per year in those aged <55 years but increased steadily with age (3.6, 8.6, and 14.2/1000 per year in aged 65-69, 75-79, and ≥80 years, respectively). Compared with individuals without ACHD, ACHD patients aged <50 years and those aged both 50-54 and 55-59 years exhibited a 20-fold and 10-fold higher incidence of AF, respectively. Patients with complex congenital heart disease and Ebstein's anomaly had the highest risk of AF (cumulative risk >10% by age 50 and >20% by age 60), followed by those with tetralogy of Fallot, tricuspid atresia, endocardial cushion defect, and secundum atrial septal defect (cumulative risk >5% by age 50 and >10% by age 60).

CONCLUSION

Compared with individuals without ACHD, AF in patients with ACHD likely appeared 30 years earlier, with a 10- to 20-fold higher incidence plateauing around age 70. Yet, incidence in individuals without ACHD continued to increase. AF burden in patients with ACHD is not expected to increase in a never-ending way.

Splenic Torsion in Heterotaxy Syndrome with Left Isomerism: A Case Report and Literature Review

Splenic torsion is an unusual condition that results in congenital abnormality, especially in the visceral abnormal arrangement. We report the case of an 8.5-year-old boy with features in the right upper quadrant. Radiological investigations revealed heterotaxy syndrome with polysplenia and a hypodense tumor in the right upper quadrant adjacent to several spleens. We initially treated it as an intra-abdominal tumor. Laparoscopy was performed to check the tumor condition and revealed a congestive tumor located in the abdomen of the right upper quadrant below the central liver, which was suspected to be a torsion spleen without attaching ligaments. Laparoscopic splenectomy was successfully carried out without complications. The pathological report shows splenic tissue with hemorrhagic infarction. Physicians should be vigilant of the differential diagnosis of the acute abdomen in adolescents.

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.

Catheter Ablation of Atrioventricular Nodal Reentrant Tachycardia in Patients With Congenital Heart Disease

Atrioventricular (AV) nodal reentrant tachycardia represents the most common regular supraventricular arrhythmia in humans, and catheter ablation of the so called slow AV nodal pathway has been effectively performed for decades. In patients with congenital heart disease, a combination of different factors makes catheter ablation of AV nodal reentrant tachycardia substrate particularly challenging, including abnormal venous access to intracardiac structures, abnormal intracardiac anatomy, potentially deviant and often unpredictable sites of the specific conduction system, loss of traditional anatomic landmarks, and congenital cardiac surgery that may complicate the access to the AV nodal area. Published experiences have confirmed the efficacy and the relative safety of such procedures when performed by experts, but the risk of complications, in particular AV block, remains non-negligible. A thorough knowledge and understanding of anatomic and electrical specificities according to underlying phenotype are essential in addressing these complex cases. Considering the major consequences associated with AV block in patients with complex congenital heart disease, particularly those without low risk access for transvenous ventricular pacing (eg, single ventricle physiology or Eisenmenger syndrome), the individual risk-benefit ratio should be carefully evaluated. The decision to defer ablation may be the wisest approach in selected patients with either infrequent or hemodynamically tolerated arrhythmias, or when the location of the AV conduction pathways remains uncertain. This narrative review aims to synthetize existing literature on catheter ablation of AV nodal reentrant tachycardia in congenital heart disease, to present main features of common associated pathologies, and to discuss approaches to mapping and safely ablating the slow AV nodal pathway in challenging cases.

Multicenter Outcomes of Catheter Ablation for Atrioventricular Reciprocating Tachycardia Mediated by Twin Atrioventricular Nodes

OBJECTIVES

This study sought to describe the electrophysiologic properties and catheter ablation outcomes for T-AVRT.

BACKGROUND

Although catheter ablation for atrioventricular (AV) reciprocating tachycardia via twin AV nodes (T-AVRT) is an established entity, there are few data on the electrophysiological properties and outcomes of this procedure.

METHODS

An international, multicenter study was conducted to collect retrospective procedural and outcomes data for catheter ablation of T-AVRT.

RESULTS

Fifty-nine patients with T-AVRT were identified (median age at procedure, 8 years [interquartile range, 4.4-17.0 years]; 49% male). Of these, 55 (93%) were diagnosed with heterotaxy syndrome (right atrial isomerism in 39, left atrial isomerism in 8, and indeterminate in 8). Twenty-three (39%) had undergone Fontan operation (12 extracardiac, 11 lateral tunnel). After the Fontan operation, atrial access was conduit or baffle puncture in 15 (65%), fenestration in 5 (22%), and retrograde in 3 (13%). Acute success was achieved in 43 (91%) of 47 attempts (targeting an anterior node in 23 and posterior node in 24). There was no high-grade AV block or change in QRS duration. Over a median of 3.8 years, there were 3 recurrences. Of 7 patients with failed index procedure or recurrent T-AVRT, 6 (86%) were associated with anatomical hurdles such as prior Fontan or catheter course through an interrupted inferior vena cava-to-azygous vein continuation (P = 0.11).

CONCLUSIONS

T-AVRT can be targeted successfully with low risk for recurrence. Complications were rare in this population. Anatomical challenges were common among patients with reduced short and long-term efficacy, representing opportunities for improvement in procedural timing and planning.

QTc Prolongation in COVID-19 Patients Using Chloroquine

Chloroquine is used in the treatment of patients with COVID-19 infection, although there is no substantial evidence for a beneficial effect. Chloroquine is known to prolong the QRS and QTc interval on the ECG. To assess the effect of chloroquine on QRS and QTc intervals in COVID-19 patients, we included all inpatients treated with chloroquine for COVID-19 in the Spaarne Gasthuis (Haarlem/Hoofddorp, the Netherlands) and had an ECG performed both in the 72 h before and during or at least 48 h after treatment. We analyzed the (change in) QRS and QTc interval using the one-sample t-test. Of the 106 patients treated with chloroquine, 70 met the inclusion criteria. The average change in QRS interval was 6.0 ms (95% CI 3.3–8.7) and the average change in QTc interval was 32.6 ms (95% CI 24.9–40.2) corrected with the Bazett’s formula and 38.1 ms (95% CI 30.4–45.9) corrected with the Fridericia’s formula. In 19 of the 70 patients (27%), the QTc interval was above 500 ms after start of chloroquine treatment or the change in QTc interval was more than 60 ms. A heart rate above 90 bpm, renal dysfunction, and a QTc interval below 450 ms were risk factors for QTc interval prolongation. Chloroquine prolongs the QTc interval in a substantial number of patients, potentially causing rhythm disturbances. Since there is no substantial evidence for a beneficial effect of chloroquine, these results discourage its use in COVID-19 patients.

Role of a Pediatric Cardiologist in the COVID-19 Pandemic

Coronavirus disease 2019 (COVID-19) has affected patients across all age groups, with a wide range of illness severity from asymptomatic carriers to severe multi-organ dysfunction and death. Although early reports have shown that younger age groups experience less severe disease than older adults, our understanding of this phenomenon is in continuous evolution. Recently, a severe multisystem inflammatory syndrome in children (MIS-C), with active or recent COVID-19 infection, has been increasingly reported. Children with MIS-C may demonstrate signs and symptoms of Kawasaki disease, but also have some distinct differences. These children have more frequent and severe gastrointestinal symptoms and are more likely to present with a shock-like presentation. Moreover, they often present with cardiovascular involvement including myocardial dysfunction, valvulitis, and coronary artery dilation or aneurysms. Here, we present a review of the literature and summary of our current understanding of cardiovascular involvement in children with COVID-19 or MIS-C and identifying the role of a pediatric cardiologist in caring for these patients.