A Novel Right Ventricular Volume and Pressure Loaded Piglet Heart Model for the Study of Tricuspid Valve Function.

Heart conditions in which the tricuspid valve (TV) faces either increased volume or pressure stressors are associated with premature valve failure. Mechanistic studies to improve our understanding of the underlying pathophysiology responsible for the development of premature TV failure are lacking. Due to the inability to conduct these studies in humans, an animal model is required.

Effects of Early Myocardial Postnatal Maturation on Tolerance to Atrial Tachycardia With Altered Loading Conditions: An Swine Model.

Post-natal maturation of the myocardium starts shortly after birth and could affect how clinicians should provide hemodynamic support during this transition. Our aim was to assess the impact of post-natal maturation on tolerance to tachycardia with altered loading condition in a piglet model. We report three series of experimentations.

Implantation of the Melody transcatheter pulmonary valve PB1016 in patients with dysfunctional right ventricular outflow tract conduits.

Objectives: This study describes procedural and 1-year outcomes of the 16 mm Melody PB1016 valve in patients with dysfunctional RVOT conduits.

Background: The Melody PB1016 is a standard Melody valve produced from a 16 mm bovine jugular vein and is intended for deployment up to 20 mm.

Methods: This is a prospective, non-randomized, multicenter study of the procedural and short-term outcomes of Melody PB1016 TPV replacement within dysfunctional RVOT conduits.

Strain Rate in Children and Young Piglets Mirrors Changes in Contractility and Demonstrates a Force-Frequency Relationship.

Background: In adult humans and pig models, strain rate (SR) correlates strongly with invasive measures of contractility but does not demonstrate a force-frequency relationship, which is a fundamental behavior of myocardial contraction. Given the considerable maturational changes of the myocardium from fetal stages to adulthood, extrapolation of adult findings to the young heart may not be appropriate. We sought to evaluate the SR response of the immature heart to increased heart rate (HR) and inotropic stimulation.

Acoustic diagnosis of pulmonary hypertension: automated speech- recognition-inspired classification algorithm outperforms physicians.

We hypothesized that an automated speech- recognition-inspired classification algorithm could differentiate between the heart sounds in subjects with and without pulmonary hypertension (PH) and outperform physicians. Heart sounds, electrocardiograms, and mean pulmonary artery pressures (mPAp) were recorded simultaneously. Heart sound recordings were digitized to train and test speech-recognition-inspired classification algorithms.

Postnatal neonatal myocardial adaptation is associated with loss of tolerance to tachycardia: a simultaneous invasive and noninvasive assessment.

Doppler studies at rest suggest left ventricular (LV) diastolic function rapidly improves from the neonate to infant. Whether this translates to its response to hemodynamic challenges is uncertain. We sought to explore the impact of early LV maturation on its ability to tolerate atrial tachycardia.

Detection of Heart Sounds in Children with and without Pulmonary Arterial Hypertension--Daubechies Wavelets Approach.

Background: Automatic detection of the 1st (S1) and 2nd (S2) heart sounds is difficult, and existing algorithms are imprecise. We sought to develop a wavelet-based algorithm for the detection of S1 and S2 in children with and without pulmonary arterial hypertension (PAH).

Method: Heart sounds were recorded at the second left intercostal space and the cardiac apex with a digital stethoscope simultaneously with pulmonary arterial pressure (PAP).

Time-domain analysis of heart sound intensity in children with and without pulmonary artery hypertension: a pilot study using a digital stethoscope.

We studied digital stethoscope recordings in children undergoing simultaneous catheterization of the pulmonary artery (PA) to determine whether time-domain analysis of heart sound intensity would aid in the diagnosis of PA hypertension (PAH). Heart sounds were recorded and stored in .wav mono audio format.

Percutaneous transhepatic stenting of a restrictive atrial septal communication in hypoplastic left heart syndrome.

The postnatal survival of patients with congenital cardiac defects such as hypoplastic left heart syndrome (HLHS) is dependent on the patency of the ductus arteriosus and the presence of an unrestrictive atrial septal defect (ASD). We report a six week old infant with HLHS and tricuspid valve regurgitation with restrictive ASD. Transfemoral balloon atrial septostomy provided temporary relief but further attempts were not possible.

Which cardiovascular magnetic resonance planes and sequences provide accurate measurements of branch pulmonary artery size in children with right ventricular outflow tract obstruction?

Children with right ventricular outflow tract obstructive (RVOTO) lesions require precise quantification of pulmonary artery (PA) size for proper management of branch PA stenosis. We aimed to determine which cardiovascular magnetic resonance (CMR) sequences and planes correlated best with cardiac catheterization and surgical measurements of branch PA size. Fifty-five children with RVOTO lesions and biventricular circulation underwent CMR prior to; either cardiac catheterization (n = 30) or surgery (n = 25) within a 6 month time frame.

Decellularization reduces immunogenicity of sheep pulmonary artery vascular patches.

Objectives: Allograft vascular tissue is important in the repair of complex structural lesions of the heart and great vessels, but induces a deleterious immune response that might shorten the effective lifespan of the tissue and sensitize the recipient. We hypothesized that decellularizing allograft vascular tissue reduces the host allogeneic immune response.

Methods: Allograft ovine pulmonary artery patches were decellularized, cryopreserved, and implanted into the descending thoracic aorta.

The effect of short-term prophylactic acetylsalicylic acid on the incidence of postpericardiotomy syndrome after surgical closure of atrial septal defects.

Postpericardiotomy syndrome (PPS), a potential complication of open heart surgery, has a variable clinical course and severity. This study evaluated the effectiveness of acetylsalicylic acid (ASA) prophylaxis in preventing PPS after surgical closure of atrial septal defects (ASDs) in pediatric patients. A retrospective review was performed for 177 patients who underwent uncomplicated ASD closure from 1986 to 2006.

NMR assessment of Me(2)SO in decellularized cryopreserved aortic valve conduits.

Introduction: Decellularized cryopreserved allograft vascular tissue may provide a nonimmunogenic scaffold that is suitable for repopulation by cells from a variety of sources, conferring the potential for growth and repair. Although dimethyl sulfoxide (Me(2)SO) is generally regarded as a safe cryoprotectant, even low levels may alter function of repopulating cells. We investigated the residual concentration of Me(2)SO in the aqueous compartment of cryopreserved ovine aortic valve conduits following decellularization.

An intra-aortic shunt prevents paralysis during aortic surgery in sheep.

Introduction: Sheep are recommended by the United States Food and Drug Administration as a model for testing cardiovascular tissue, but are particularly prone to spinal cord ischemia and subsequent paralysis during aortic cross-clamping.

Methods: A shunt consisting of a 9 cm long phosphorylcholine coated 1/4 in. (i.

Inbred or outbred? An evaluation of the functional allogenicity of farm sheep used in cardiac valve studies.

Objective: Cryopreserved allograft cardiovascular tissue elicits a strong cellular and humoral response in recipients; this may accelerate the deterioration of the allograft and complicate future heart transplantation. Juvenile sheep are the standard model for in vivo valve research and have been used to investigate the allogeneic immune response to cardiac valve and vascular tissue transplantation. Studies to date have not considered the extent of allogenicity of sheep used in transplantation studies.

Gene transfer of prostaglandin synthase maintains patency of the newborn lamb arterial duct.

In congenital heart disease with left- or right-sided obstruction, prostaglandin E (PGE)1 or PGE2 is infused to maintain ductus arteriosus (DA) patency. We hypothesized that transfection of the DA with PGE synthase would lead to a greater production of PGE2 in situ and, hence, patency of the DA. The cDNA for human prostaglandin synthase was sequenced and ligated into a eukaryotic expression vector.

Corrosive behaviour of Amplatzer devices in experimental and biological environments.

Purpose: Nitinol, a nickel-titanium alloy, is a valuable material in the construction of interventional endoluminal devices because of its biocompatibility, super elasticity, high resiliency and shape memory. The possibility of nickel toxicity has been raised with devices constructed of Nitinol. Our investigation examines the long-term corrosive behavior of this alloy in experimental and biological environments.