Non-invasive detection of acute allograft rejection in children by tissue Doppler imaging: myocardial velocities and myocardial acceleration during isovolumic contraction.

Background: In adults, an acute decrease of regional myocardial velocities is a sensitive marker of rejection. In children, velocities are more variable. A new marker, myocardial acceleration during isovolumic contraction (IVA), appears to be less age-dependent than myocardial velocities.

Double-orifice mitral valve with intact atrioventricular septum: an echocardiographic study with anatomic and functional considerations.

We identified 18 patients with double-orifice mitral valve (DOMV) and intact atrioventricular (AV) septum out of 40,179 echocardiographic studies performed between 1997 and 2002 at Children's Hospital, Denver, CO. In this study we describe (1) the anatomic characteristics of the DOMV in the absence of AV septal defect, (2) the function of the mitral valve by spectral and color Doppler flow mapping, and (3) associated lesions. The topographic location of the orifices in the leaflets suggests possible embryologic mechanisms of DOMV.

Hypertension in mice lacking the proatrial natriuretic peptide convertase corin.

Atrial natriuretic peptide (ANP) is a cardiac hormone that regulates blood pressure. In cardiomyocytes, the hormone is synthesized as a precursor, proatrial natriuretic peptide (pro-ANP), which is proteolytically converted to active ANP. Corin is a cardiac transmembrane serine protease that has been shown to process pro-ANP in vitro, but its physiological importance had not been established.

Mixed total anomalous pulmonary venous connection: Case report with bilateral venous collectors.

We present a case report of a 3-month-old boy with a mixed total anomalous pulmonary venous connection. The patient had situs solitus, small atrial septal defect, and 2 separate venous collectors. The right pulmonary veins drained through a right-sided venous collector into the coronary sinus.

Longitudinal motion of the atrioventricular annuli in children: reference values, growth related changes, and effects of right ventricular volume and pressure overload.

The goals of this study were to characterize normal patterns of longitudinal motion of atrioventricular annuli in the young, establish reference values and assess growth-related changes (n = 40). Sensitivity to changes in right ventricular volume and pressure load was assessed in patients with atrial septal defect (ASD) (n = 25) and with primary pulmonary hypertension (PPH) (n = 20). M-mode of the annuli were obtained from apical views.

A general method for estimating deformation and forces imposed in vivo on bioprosthetic heart valves with flexible annuli: in vitro and animal validation studies.

Background And Aim Of The Study: The use of flexible structures within cardiovascular prostheses such as valves, stents and vascular grafts has been proposed as a means of more closely modeling native mechanics, and thereby reducing the biomechanical problems associated with rigid materials. However, the design of such materials has been hampered by the paucity of quantitative information on the in-vivo behavior of such structures. The aim of this study was to explore the use of 3D ultrasound imaging coupled with finite element analysis (FEA) as a tool to estimate deformation and forces imposed in vivo on a novel bioprosthetic valve design.

Echocardiographic outcome of infants treated as newborns with inhaled nitric oxide for severe hypoxemic respiratory failure.

Objective: To determine the cardiovascular outcome of a group of term newborns treated with inhaled nitric oxide (iNO) for severe hypoxemic respiratory failure with associated persistent pulmonary hypertension.

Study Design: We performed echocardiographic evaluations in 40 survivors treated for severe neonatal hypoxemic respiratory failure. Each of the 40 had at least 2 follow-up echocardiograms at 3 or 6 and 24 months.

Three-dimensional imaging of aortic arch anomalies in infants and children with intravascular ultrasound catheters from a transesophageal approach.

Aortic arch anomalies usually require surgical intervention preceded by precise anatomic definition. We studied 20 patients to evaluate the feasibility and accuracy of using intravascular ultrasound catheters from a transesophageal approach with 3-dimensional image reconstruction for the diagnosis of aortic arch anomalies in infants and children. All patients had transthoracic echocardiograms and/or angiograms or magnetic resonance imaging.

Intravascular ultrasonic characteristics and vasoreactivity of the pulmonary vasculature in children with pulmonary hypertension.

We sought to describe the morphologic characteristics of pulmonary arteries by intravascular ultrasound (IVUS) in children with and without pulmonary hypertension to compare these anatomic findings with those of pulmonary wedge angiography, and to determine the relation between these structural findings and functional reactivity to pulmonary vasodilators. Direct evaluation of pulmonary vascular structure in children with pulmonary hypertension with current imaging techniques has been limited and little is known about the relation between structural and functional characteristics of the pulmonary vasculature. In 23 children undergoing cardiac catheterization (15 with pulmonary hypertension and 8 controls) we performed IVUS and pulmonary wedge angiography of the distal pulmonary arteries in the same lobe.

Color Doppler regurgitant jet area for evaluating eccentric mitral regurgitation: an animal study with quantified mitral regurgitation.

Objectives: The purpose of the present study was to rigorously evaluate the accuracy of the color Doppler jet area planimetry method for quantifying chronic mitral regurgitation.

Background: Although the color Doppler jet area has been widely used clinically for evaluating the severity of mitral regurgitation, there have been no studies comparing the color jet area with a strictly quantifiable reference standard for determining regurgitant volume.

Methods: In six sheep with surgically produced chronic mitral regurgitation, 24 hemodynamically different states were obtained.

Optimization character of inspiratory neural drive.

A previous optimal chemical-mechanical model (C.-S. Poon.

Transvascular intracardiac applications of a miniaturized phased-array ultrasonic endoscope. Initial experience with intracardiac imaging in piglets.

Background: Recent advances in miniaturization of phased-array and mechanical ultrasound devices have resulted in exploration of alternative approaches to cardiac and vascular imaging in the form of transesophageal or intravascular imaging. Preliminary efforts in adapting phased-array endoscopes designed for transesophageal use to a transvascular approach have used full-sized phased-array devices introduced directly into the right atrium in open-chested animals. The purpose of this study was to assess the feasibility of using a custom-made, very small phased-array endoscope for intracardiac imaging introduced intravascularly through a jugular venous approach in young piglets.