Upcoming Events in Pediatric Cardiology

Chemotherapy-Induced Cardiotoxicity in Adolescent After Heart Transplant: Do Not Forget the Right Ventricle Abstract The evaluation of oncologic patients at risk of chemotherapy-induced cardiotoxicity usually focuses on left ventricular function. However, recent studies have demonstrated that right ventricle impairment often coexists (and in some cases precedes) left-side affectation. We present the case of a 19-year-old heart transplant recipient who developed severe right ventricular dysfunction secondary to treatment of an abdominal lymphoma.

Double Orifice Mitral Valve in Tricuspid Atresia: A Rare Association Abstract We here report a neonate with prenatal echocardiographic diagnosis of tricuspid atresia, with normally related great vessels, and large ventricular septal defect. This diagnosis could be confirmed with echocardiography at birth. An additional double mitral orifice was also seen. This is a very rare association.

Herniated Liver Mimicking Right Atrial Mass Abstract In a newborn that underwent surgery due to omphalocele, postoperative echocardiography revealed an accidental finding of a right atrial (RA) mass. Echocardiography prior to surgery was inconspicuous. Applying color Doppler, a pulsatile flow exiting the mass could be depicted and a tubular structure lancing through the mass. Thrombus formation was suspected. However, sonographic tissue texture of this formation equaled liver tissue. Abdominal ultrasound revealed protrusion of hepatic tissue through a diaphragmatic hernia indenting the RA mimicking a thrombus.

Heart Transplantation from Biventricular Support in Infant with Novel SMYD1 Mutation Abstract SET and MYND domain-containing protein 1 (SMYD1) has been shown to be responsible for the development of fast twitch and cardiac muscle. Mutations in SMYD1 have been shown to be uniformly fatal in laboratory studies, and not previously described in living humans. We describe here the care of an infant suffering from cardiac failure due to an SMYD1 mutation requiring biventricular assist devices as a bridge to successful heart transplantation. The patient is now doing well 2 years post-transplant and represents a known survivor of a suspected uniformly fatal genetic mutation.

Two Cases of a Prenatally Diagnosed Double Aortic Arch with Postnatal Obliteration of the Distal Left Aortic Arch Abstract We report two cases of prenatally diagnosed double aortic arch with dominant right arch and a left-sided ductus arteriosus, consistent with a complete vascular ring. Postnatal transthoracic echocardiogram and cardiac magnetic resonance imaging demonstrated a spontaneous closure of the ductus arteriosus and obliteration of the left aortic arch distal to the origin of the left subclavian artery in both cases. Spontaneous closure of the ductus arteriosus involving extended ductal tissue in the left aortic arch likely led to obliteration of the distal left arch after birth. One patient presented with recurrent symptoms suggestive of dysphagia and underwent a successful surgical repair of the vascular ring with resolution of symptoms. The other patient has been asymptomatic and is 4 years old at the time of this report.

Covered Stent as a Bridge to Surgery for Obstructive Melody Pulmonary Valve Endocarditis Abstract Endocarditis is life threatening after percutaneous pulmonary valve implantation. We report a patient with acute heart failure caused by obstructive pulmonary vegetation in a Melody valve. Because of severe right ventricular dysfunction, immediate cardiac surgery was contraindicated. The patient underwent trans-catheter implantation of a covered stent to relieve obstruction. Following an initially good outcome, surgery was performed 2 weeks later. This was complicated by left main coronary artery tear and fatal bleeding. Despite covered stent was an effective bridge, surgery remains extremely challenging in such cases with important surrounding inflammation and fibrosis as well as potential proximity of coronary arteries.

Reclassification of Variants of Uncertain Significance in Children with Inherited Arrhythmia Syndromes is Predicted by Clinical Factors Abstract Genetic testing is important to augment clinical diagnosis and inform management of inherited arrhythmias syndromes (IAS), but variants of uncertain significance (VUS) are common and remain a challenge in clinical practice. In 2015, American College of Medical Genetics (ACMG) published updated guidelines for interpretation of genetic results. Despite increasing understanding of human genomic variation, there are no guidelines for reinterpretation of prior genetic test results. Patients at a single tertiary children’s hospital with genetic testing for an IAS that demonstrated a VUS were re-evaluated using 2015 ACMG guidelines, clinical information, and publically available databases. Search of the electronic medical record identified 116 patients with genetic testing results available, and 24/116 (21%) harbored a VUS for an IAS. 23 unique VUS were evaluated from 12 genes. Over half of the VUS (12/23 (52%)) were reclassified using 2015 criteria, and 8 (35%) changed to pathogenic and 4 (17%) to benign. Relative risk of reclassification of VUS to a pathogenic variant in a patient with confirmed clinical diagnosis was 4.1 (95% CI 1.23–15.4). Reclassification was not associated with initial testing year. These data demonstrate 52% of VUS in children with IAS are reclassified with application of 2015 ACMG guidelines. Strength of phenotyping is associated with eventual pathogenic classification of genetic variants and periodic re-evaluation of VUS identified on genetic testing for IAS is warranted.

Left Ventricular Diastolic Dysfunction and Diastolic Heart Failure in Preterm Infants Abstract Diastolic dysfunction is primarily an echocardiographic diagnosis. Its clinical counterpart is diastolic heart failure, where the heart has difficulty to fill at normal pressure and the patient develops signs of pulmonary edema. Although diastolic dysfunction is common in adults, limited information is available in preterm infants. The aim of this study is to explore left ventricular diastolic dysfunction and diastolic heart failure in preterm infants and describe clinical manifestations in this population. This is a retrospective observational study in preterm infants < 30 weeks’ gestation who received an echocardiography in the first 4 weeks after birth. Diastolic dysfunction was graded using a population-specific adapted version of the adult recommendations for the evaluation of left ventricular diastolic function by echocardiography. Left ventricular diastolic dysfunction was absent, indeterminate, and definite in 82%, 14%, and 4% of the 168 echocardiograms analyzed, and is associated with increased respiratory signs and respiratory deterioration at 48 h before echocardiogram. In seven infants, diastolic heart failure was diagnosed with both ultrasound and clinical signs. The cumulative risk of diastolic dysfunction increased with the increasing postnatal age and a patent ductus arteriosus. Evidence of left ventricular diastolic dysfunction on echocardiography is relatively common in preterm infants, while the left ventricular diastolic heart failure is less frequent. Prolonged exposure to volume load was the most common cause.

The Limited Benefit of Follow-Up Echocardiograms After Repair of Tetralogy of Fallot Abstract Tetralogy of Fallot (ToF) is the most common cyanotic congenital heart disease, making up 10% of all congenital heart defects. Annual follow-up echocardiograms are recommended in patients with repaired ToF, but evidence-based guidelines do not exist. We hypothesized that most echocardiograms performed in asymptomatic patients with repaired ToF and no physical exam change do not result in an actionable change (AC) in management. We retrospectively reviewed records of all patients with ToF and prior complete repair at our institution between January 2000 and September 2015. Changes in echocardiograms resulting in hospital admission, medication addition/change, cardiac catheterization, or surgical procedure were identified via chart review. These changes were referred to as an AC. A total of 1135 echocardiograms were reviewed from 233 patients (160 with initial complete repair, 70 with prior shunt, and 3 with other initial surgery). The median number of echocardiograms per patient was 5. Of the 1135 echocardiograms, 15 (1.3%) were associated with AC. Of the 15 patients with AC echocardiograms, 9 underwent a shunt prior to complete repair (9/70, 12.9%) and 6 had undergone an initial complete repair (6/160, 3.8%). The median age at AC was 6.3 years (IQR 4.4, 6.8) in the shunt group and 0.90 years (IQR 0.87, 1.1) in the initial complete repair group. In asymptomatic patients with repaired ToF and no physical exam change, echocardiograms rarely lead to a change in clinical management. In conclusion, the likelihood and timing of AC echocardiograms and reinterventions vary based on the type of initial surgery.