Steroid-associated bradycardia in a newly diagnosed B precursor acute lymphoblastic leukemia patient with Holt-Oram syndrome.

Holt-Oram syndrome (HOS) (OMIM#142900) is a rare condition with upper extremity malformations as well as structural and conduction cardiac anomalies. There are sparse reports in the literature documenting malignancy in association with HOS. We report a pediatric patient clinically diagnosed with HOS (missing thumbs bilaterally, atrial septal defect, ventricular septal defect, and first-degree heart block), who also developed B precursor acute lymphoblastic leukemia.

Complicated ventricular arrhythmia and hematologic myeloproliferative disorder in RIT1-associated Noonan syndrome: Expanding the phenotype and review of the literature.

Background: Noonan syndrome is an autosomal dominant disorder secondary to RASopathies, which are caused by germ-line mutations in genes encoding components of the RAS mitogen-activated protein kinase pathway. RIT1 (OMIM *609591) was recently reported as a disease gene for Noonan syndrome.

Methods And Results: We present a patient with RIT1-associated Noonan syndrome, who in addition to the congenital heart defect, had monocytosis, myeloproliferative disorder, and accelerated idioventricular rhythm that was associated with severe hemodynamic instability.

Determination of the Frequency of Right and Left Internal Mammary Artery Embolization in Single Ventricle Patients: A Two-Center Study.

Embolization of systemic to pulmonary artery collaterals to regulate pulmonary arterial flow or pressure of the cavopulmonary circulation in patients with single ventricle is a common practice. The relative incidence and impact of this practice on future interventions like coronary artery bypass grafting is poorly understood. This study aims to evaluate the frequency and implications of internal mammary artery (IMA) embolization in the single ventricle (SV) population.

Acute Pediatric Colchicine Toxicity is Associated with Marked Bradydysrhythmias.

Background: Colchicine ingestion is rare but highly lethal. Patients usually die of multiorgan failure and cardiogenic shock. Colchicine is not only associated with depressed myocardial function but also with fatal heart rhythm disturbances, such as complete heart block, ventricular tachycardia, and asystole.