Computational fluid dynamics simulations as a complementary study for transcatheter endovascular stent implantation for re-coarctation of the aorta associated with minimal pressure drop: an aneurysmal ductal ampulla with aortic isthmus narrowing.

Background: Transcatheter stent implantation has been employed to treat re-coarctation of the aorta in adolescents and young adults. The aim of this work is to use computational fluid dynamics to characterise haemodynamics associated with re-coarctation involving an aneurysmal ductal ampulla and aortic isthmus narrowing, which created minimal pressure drop, and to incorporate computational fluid dynamics's findings into decision-making concerning catheter-directed treatment.

Methods: Computational fluid dynamics permits numerically solving the Navier-Stokes equations governing pulsatile flow in the aorta, based on patient-specific data.

Polyvalvular heart disease syndrome.

An adult case of polyvalvular heart disease syndrome diagnosed in an adult is presented. The characteristic facies and echocardiographic features of this rare autosomal dominant connective tissue disorder are presented.

Adult presentation of ALCAPA: Echo and CT diagnosis.

A healthy 20-year-old male presented with aborted sudden death. Both thoracic echocardiography and cardiac computed tomographic angiography demonstrated the characteristic findings of ALCAPA noting a dilated and tortuous right coronary artery, dilated coronary collateral arteries within the interventricular septum or along the surface of the heart, and visualization of the left coronary artery origin from the posterior aspect of the main pulmonary artery. Both imaging modalities demonstrated all three characteristic findings of this rare coronary anomaly and served as complementary imaging studies for surgical correction.

Computational fluid dynamics characterization of pulsatile flow in central and Sano shunts connected to the pulmonary arteries: importance of graft angulation on shear stress-induced, platelet-mediated thrombosis.

Objectives: Central (aorta) and Sano (right ventricle)-to-pulmonary artery (PA) shunts, palliative operations for infants with complex heart defects, can develop life-threatening thrombosis. We employed computational fluid dynamics (CFD) to study pulsatile flow in these shunts, with the goal to identify haemodynamic characteristics conducive to thrombus formation.

Methods: CFD, using the finite volume method with cardiac catheterization data, and computer simulations, based on angiography, were employed to determine flow-velocity field, wall shear stress (WSS) profile and oscillatory shear index (OSI).

Electrocardiac effects associated with lithium toxicity in children: an illustrative case and review of the pathophysiology.

Lithium is a potent psychotherapeutic agent that has gained wide acceptance in paediatrics, especially as adjunct treatment for severe behavioural, anxiety, and attention-deficit hyperactivity disorders, along with bipolar conditions. Its cardiac toxicity has been well-documented in adults; however, information is limited regarding lithium's effects on the heart in children. Therefore, paediatric cardiologists following-up children on lithium therapy should be cognizant of the cardiac side-effects and pathophysiology associated with this drug.

Computational fluid dynamics characterization of blood flow in central aorta to pulmonary artery connections: importance of shunt angulation as a determinant of shear stress-induced thrombosis.

The central aortic shunt, consisting of a Gore-Tex (polytetrafluoroethylene) tube (graft) connecting the ascending aorta to the pulmonary artery, is a palliative operation for neonates with cyanotic congenital heart disease. These tubes often have an extended length, and therefore must be angulated to complete the connection to the posterior pulmonary arteries. Thrombosis of the graft is not uncommon and can be life-threatening.

Pseudotumor cerebri associated with modified Fontan anatomy.

Surgical treatment of functional single-ventricle heart disease with a modified Fontan procedure results in elevated central venous pressure. The case report describes a 19-year-old boy with hypoplastic left heart syndrome and Fontan palliation that resulted in frequent debilitating headaches after transcatheter closure of systemic venous-to-pulmonary venous collaterals. Measured increased intracranial pressure and prompt relief of the headaches with lumbar puncture favored a diagnosis of pseudotumor cerebri.

Surgical improvement of hepatic venous mixing to resolve systemic arterial hypoxemia associated with post-Fontan pulmonary arteriovenous fistulae.

Pulmonary arteriovenous fistulae are known to develop in patients who have functional single-ventricle heart disease and interruption of the inferior vena cava with direct hepatic drainage to the heart, in which a bidirectional Glenn shunt is the only source of pulmonary blood flow. The progressive systemic arterial hypoxemia that is associated with pulmonary arteriovenous fistulae can have important clinical consequences. Baffling the hepatic venous return to the pulmonary circulation can alleviate pulmonary arteriovenous fistulae.

Bidirectional Glenn shunt as an adjunct to surgical repair of congenital heart disease associated with pulmonary outflow obstruction: relevance of the fluid pressure drop-flow relationship.

A bidirectional Glenn shunt (BGS) was successfully incorporated into a two-ventricle repair for 10 patients (age, 3-17 years) who had congenital heart disease associated with severe pulmonary outflow obstruction. The BGS was used to volume-unload the pulmonary ventricle faced with residual outflow obstruction, thereby avoiding the need for insertion of a ventricle-to-pulmonary artery conduit. Transthoracic Doppler flow velocity analysis was used to determine transpulmonary peak systolic pressure drops as a measure of obstruction.

Complete unilateral leg duplication with ipsilateral renal agenesis.

Unlabelled: A case of a 5-month-old infant with complete duplication of the right leg and ipsilateral renal agenesis is presented. There was also a duplicated scrotum, posterior urethral valves with hydronephrosis, abnormal pelvic bones, and a ventricular septal defect. Complete caudal duplication is exceedingly rare.

Recovery of the chronically hypoxic young rabbit heart reperfused following no-flow ischemia.

The objective of this study was to test whether chronically hypoxic immature hearts exhibit greater tolerance to no-flow ischemia than normoxic hearts. Rabbits (N = 36) were raised from birth to 5 weeks of age in either hypoxic (10% O2/90% N2) or normoxic (room air) environment. Isolated, isovolumically beating hearts, with a fluid-filled balloon catheter in the left ventricular chamber, were perfused with a well-oxygenated buffer and studied during baseline [30 minutes; perfusion pressure, 60 mmHg; end diastolic pressure (EDP), 5 mmHg], no-flow ischemia (until onset of contracture or for 30 minutes), and Reperfusion (30 minutes; perfusion pressure, 60 mmHg).

Analysis of pulmonary vascular response to acute alveolar hypoxic challenge in young rabbits subjected to chronic hypoxia from birth.

Chronic alveolar hypoxia induces vascular changes leading to pulmonary hypertension. We investigated the role of nitric oxide synthase (NOS) on basal pulmonary artery pressure (PAP) and on changes in PAP arising from an acute alveolar hypoxic challenge (AAHC) in normoxic and chronically hypoxic young rabbits. The chronically hypoxic rabbits were raised from birth in a chamber containing a (10% O2 + 90% N2) gas mixture, whereas the normoxic rabbits were kept in room air.

Systematic-to-pulmonary collaterals: a source of flow energy loss in Fontan physiology.

Patients with Fontan-modified, single-ventricle heart frequently have systemic collaterals that increase pulmonary blood flow. Competitive flow from these auxiliary vessels can also elevate pulmonary artery pressure, a process leading to erosion of flow's mechanical energy. An analogous analytical description of mixing fluid streams was used to provide insight into flow energetics associated with systemic-to-pulmonary collaterals in Fontan-type circulation.

Performance of the chronically hypoxic young rabbit heart.

Hearts isolated from 30 rabbits, raised from birth to approximately 5 weeks of age under either hypoxic (FIO2, 0.10) or normoxic (FIO2, 0.21) conditions, underwent retrograde aortic perfusion using a non-recirculating, well-oxygenated crystalloid solution.

Medtronic freestyle valves in right ventricular outflow tract reconstruction.

Background: Various pulmonary valve substitutes, with their inherent limitations, have been used in children and young adults. We chose the Medtronic Freestyle (Medtronics, Minneapolis, MN) valve because of its excellent hemodynamics, known durability in adults, and design features that allow modifications during implantation.

Methods: Over a 3 1/2 year period the Freestyle valve was implanted in 47 patients age 2 to 58 years (mean 14.

Performance of the neonatal pig heart subjected to oxygen insufficiency.

Isolated, paced, isovolumically beating, neonatal pig (n = 32) hearts underwent retrograde aortic perfusion with a solution containing insulin (100 microU/ml), glucose (5.5 mM), and palmitate (0.55 mM).

Streamlining fluid pathways lessens flow energy dissipation: relevance to atriocavopulmonary connections.

Flow energy dissipation reduces cardiac efficiency, particularly in the Fontan-modified, single-ventricle heart. To provide insight into flow energetics relevant to Fontan-type anatomy, a simple, analytical description of fluid motion was employed. Mechanical energy balance and the force-momentum relationship were used to describe theoretical pressure changes and flow energy losses.

Pressure loss from flow energy dissipation: relevance to Fontan-type modifications.

Pressure loss from flow energy dissipation may impair cardiac performance when a heart with a single ventricle must support the circulation. Therefore, the goal of this study was to use a simple description of fluid motion to provide insight into flow energetics relevant to Fontan-type procedures. Our findings indicate that when either the cross-sectional area or the axial direction of flow changes "abruptly," disturbances are set up within the fluid that lead to dissipation of available energy.

A direct comparison of right and left ventricular performance in the isolated neonatal pig heart.

A comparison is presented between the performance of the right ventricle (RV) and the left ventricle (LV) in neonatal hearts studied under conditions of volume loading and tachycardia. Isolated, atrially paced (150 or 300 bpm), isovolumically beating pig hearts (1-3 days of age) underwent retrograde aortic perfusion with a nonrecirculating, crystalloid solution. Ventricular pressure was assessed with saline-filled balloon catheters, which allowed separate loading of the RV or LV.

Mechanical function and substrate oxidation in the neonatal pig heart subjected to pacing-induced tachycardia.

Isolated, paced, isovolumically beating, neonatal pig ( approximately 2 days) hearts were perfused with a crystalloid solution during four periods: (1) baseline, HR 150 bpm; (2) HR-response curves, HR 150-360 bpm; (3) tachycardia, HR 300 bpm; and (4) posttachycardia, HR 150 bpm. Group I was studied with glucose (5. 5 mM) as the sole substrate.

Innominate artery steal syndrome after stage I palliation for hypoplastic left heart syndrome.

Four neonates with hypoplastic left heart syndrome (HLHS) were found to have innominate artery steal syndrome (IASS) following stage I palliation with a modified Blalock-Taussig (B-T) shunt. All patients presented in the early postoperative period with a persistent supplemental oxygen requirement. Two-dimensional echocardiography with Doppler flow analysis and cardiac catheterization with angiography demonstrated obstruction at the origin of the innominate artery.

Analysis of cardiovascular responses to PACAP-27, PACAP-38, and vasoactive intestinal polypeptide.

Responses to pituitary adenylate cyclase polypeptide (PACAP)-27, PACAP-38, and vasoactive intestinal peptide (VIP) were compared in the peripheral and pulmonary vascular beds of the cat and in the isolated perfused neonatal pig heart. Intravenous injections of PACAP-27 and PACAP-38 produced biphasic changes in systemic arterial pressure whereas iv injections of VIP caused only decreases in arterial pressure. When blood flow to the hind limb and mesenteric vascular beds was maintained constant, PACAP-27 and PACAP-38 caused dose-related biphasic changes in perfusion pressure, whereas VIP only decreased perfusion pressure.

Substrate metabolism in the developing heart.

The developing heart undergoes a remarkable metabolic transformation as it adjusts to the higher-oxygen, extrauterine environment. During gestation, glycolysis and lactate oxidation constitute the major sources of adenosine triphosphate (ATP) for the fetal heart. After birth, however, there is a rapid shift from carbohydrate to fatty acid utilization.

Contractile and coronary vascular effects of pituitary adenylate cyclase activating polypeptide in neonatal pig hearts.

Objective: The purpose was to investigate the influence of the 38-amino-acid neuropeptide, pituitary adenylate cyclase activating polypeptide (PACAP38), on contractile function and coronary vascular tone in neonatal hearts.

Methods: Isolated, paced (150 bpm), isovolumically-beating, piglet hearts (n = 19) underwent retrograde aortic perfusion at constant coronary flow (approximately 2.5 ml/min/gwet) with an erythrocyte-enriched (Hct 15-20%) solution (37 degrees C).