Biomedical subjects

Gregory J Wilson

Publications and source records attributed to Gregory J Wilson.

At least 19 recordsLinked to original sources

PubMed2006

Cardiac perforation 6 weeks after percutaneous atrial septal defect repair using an Amplatzer septal occluder.

A 14-year-old boy presented to the emergency department unaccompanied by his parents with a decreased level of consciousness, bradycardia, and hypotension after a syncopal episode. The patient's electronic chart revealed a percutaneous closure of a secundum atrial septal defect using an Amplatzer septal occluder (AGA Medical, Golden Valley, MN) 6 weeks before this presentation. An urgent echocardiogram revealed a moderate pericardial effusion, and 320 mL of fresh blood was evacuated by subxiphoid pericardiocentesis. The child underwent surgical exploration and was found to have a perforation in the superior-posterior aspect of the right atrium, which was corrected. The septal occluder was extracted, and the atrial septal defect was closed with a pericardial patch. This case illustrates a rare but life-threatening complication of percutaneous closure of atrial septal defect using an Amplatzer septal occluder and the importance of timely access to patient records when available history and physical examination are limited.

Adolescent↗

PubMed2006

Chemical discrimination by a kinetic model of organic photooxidation in a heterosupramolecular assembly.

The photooxidation of range of common organic pollutants in a dye-sensitised photoelectrochemical cell (DS-PEC) is reported. A photoanode was prepared by the chemisorption of a photosensitiser, cis-bis-(2,2)-bipyridine)-(4,4'-bis-(methyl)phosphonato-2,2'-bipyridine)ruthenium(II) dichloride ([Ru(bpy)2(dmpbpy]2+), to a nanoporous nanocrystalline TiO2 thin film on a conducting glass substrate. The photoanode was coupled to a platinum electroplated fluorine doped tin oxide glass substrate in a two electrode assembly and the cell cavity was filled with an aqueous solution of organic pollutants and irradiated with lambda>420 nm to give a measurable photocurrent. In addition to the ability of this cell to photooxidise a range of chemically diverse organic pollutants, the application of a kinetic model to observed photocurrent transients allowed the study of interfacial electron transfer processes. Through the mathematical fit of a five-parameter double exponential decay function, evidence to support numerous interfacial reactions for the oxidation process were identified. Rapid oxidation of species in close proximity to the photooxidation centre was proposed as the kinetically fast interfacial process with a first-order rate constant of the order 0.4 s(-1). The slower process was attributed to the diffusion of oxidisable species from the solution bulk to the surface prior to oxidation with a first-order rate constant of the order 0.01 s(-1). Theoretical profiling of the kinetic events supported the biphasic assignment of interfacial processes and indicated that non-exhaustive oxidation occurs for the solution concentrations examined.

Journal Article↗

PubMed2006

Significant differences in the electrochemical behavior of the alpha-, beta-, gamma-, and delta-tocopherols (vitamin E).

Alpha-, beta-, gamma-, and delta-tocopherols can be oxidized in dry CH2Cl2 or CH3CN by one electron to form cation radicals that deprotonate to form the neutral phenoxyl radicals, which are then immediately further oxidized by one electron to the phenoxonium cations (an ECE electrochemical mechanism, where E signifies an electron transfer and C represents a chemical step, with the electrochemical mechanism having been determined by in situ spectroscopic analysis). The principal difference in the electrochemical behavior of the tocopherols relates to the stability of their associated phenoxonium cations. The phenoxonium cation of alpha-tocopherol is stable in solution for at least several hours, the phenoxonium cation of beta-tocopherol is stable for several minutes, and the phenoxonium cations of gamma- and delta-tocopherol are stable for <1 s. In dry CH2Cl2 containing >0.75 M acid (CF3COOH), the deprotonation reaction of the cation radicals can be completely inhibited resulting in the cyclic voltammetric behavior of the tocopherols appearing as chemically reversible one-electron oxidation processes (an E mechanism). In dry acid conditions, the cation radicals can be further oxidized by one electron to form the dications, which are unstable and immediately deprotonate. The high stability of the phenoxonium cation of alpha-tocopherol compared to the other tocopherols (and most other phenols) is a chemically important feature that may shed new light on understanding alpha-tocopherol's unique biological properties.

Electrochemistry↗

PubMed2006

Modification of TiO2 for enhanced surface properties: finite Ostwald ripening by a microwave hydrothermal process.

The effect of microwave modification of colloidal TiO2 suspensions under extended periods of treatment is presented. The nanoparticulate TiO2 is compared and contrasted to similar convection hydrothermally treated TiO2 and a commercial titania product, namely Degussa P25. Microwave-treated samples were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy to determine their physicochemical characteristics. Comparative surface area analyses were performed by N2 adsorption and calculated from a Brunauer-Emmett-Teller (BET) isotherm. The complementary techniques of XRD and TEM showed good correlation between observed and calculated particle sizes (by application of the Scherrer equation), with the material being highly crystalline anatase TiO2, as identified by XRD and Raman. This investigation identified that extended periods of microwave hydrothermal treatment do not greatly enhance the crystallinity and primary grain size. Treatment of >180 min has a negative effect on crystallite growth; however, treatment up to this time had a significant effect on the material's surface area. The limiting regime of Ostwald ripening for hydrothermal treatment is discussed in relation to the mechanism of microwave treatment, that is, rapid heating to temperature and extremely rapid rates of crystallization. The effect of these property modifications are further discussed in relation to photocatalytic and photoelectrochemical applications of TiO2 nanoparticles.

Journal Article↗

PubMed2006

Studying ischemic preconditioning in isolated cardiomyocyte models.

Isolated cardiomyocytes, obtained by enzymatic digestion of whole hearts, have multiple advantages, most related to their accessibility to microscopic visualization, beyond the obvious elimination of other cell types that exist in the heart. Conversely, they cannot reproduce the mechanical disruption of reperfusion hypercontracture or the vascular phenomena of leukocyte plugging and compression from interstitial edema and contracture that can lead to the no-reflow phenomenon. Nevertheless, ischemic preconditioning has been consistently demonstrated to be a potent protective mechanism in freshly isolated and cultured cardiomyocytes across multiple species, indicating that much of the innate protection of ischemic preconditioning resides in cardiomyocytes. Centrifuging freshly isolated cardiomyocytes into a pellet with only a thin layer of supernatant covered by oil has proven to be an excellent model of simulated ischemia. In culture, cardiomyocytes may be exposed to severe hypoxia only or to various protocols for simulated ischemia in which an acid/lactate-rich, hyperkalemic extracellular environment with substrate deprivation (lacking glucose) is typically added. Reperfusion is simulated by well-oxygenated media of normal ionic composition. Cardiomyocyte injury has been usually evaluated by cell membrane permeability to dyes, often under hypo-osmotic conditions (osmotic fragility) or enzyme release. A survey of the use of cardiomyocyte models to study preconditioning is presented with the emphasis on examples of the innovative measurements, increasingly involving molecular techniques, that point to an increasing future role for these models in preconditioning research and, more generally, in the mechanistic study of myocardial ischemia/reperfusion.

Adult↗

PubMed2006

Utilizing SENSE to reduce scan duration in high-resolution contrast-enhanced renal MR angiography.

PURPOSE: To evaluate the use of sensitivity encoding (SENSE) to reduce scan time and decrease detrimental artifacts arising from motion and bolus profile effects during contrast-enhanced MR angiography (CE-MRA) of the renal arteries (RAs). MATERIALS AND METHODS: A direct comparison of conventional and SENSE (acceleration factor 2) CE-MRA protocols was performed on 20 patients. Each patient underwent both scans. Both protocols achieved the same resolution, but the SENSE protocol was 50% faster and utilized a faster injection than the conventional scan. Three radiologists graded the images for image quality, artifact levels, and reader confidence. RESULTS: While the signal-to-noise ratio (SNR) decreased (26+/-5 vs. 30+/-10; P=0.04) with the SENSE protocol, the image-quality scores for four identified segments of the RAs increased or were unchanged. The largest improvements in image quality occurred in the more distal segments of the RAs. Parenchymal ringing (P=0.005) and RA blurring (P=0.006) were significantly reduced, and there was a trend toward improvement of RA ringing despite the increased injection rate. CONCLUSION: The faster SENSE scan maintained nearly the same SNR (due to faster injection of Gd-chelate), reduced artifact levels, and improved image quality ratings for the distal renal vessels.

Aged↗

PubMed2006

Intravascular hematocrit layering in equilibrium phase contrast-enhanced MR angiography of the peripheral vasculature.

PURPOSE: To evaluate intravenous hematocrit (HCT) layering detected in patent calf veins that potentially simulate filling defects seen in deep venous thrombosis (DVT). MATERIALS AND METHODS: Flow characteristics, vessel size, and enhancement patterns of veins with HCT layering were examined and compared with those of normal veins in vivo. Ex vivo studies were conducted with conventional and blood pool contrast agents to study the effects of MRI parameters and intrinsic variables on detecting HCT layering. RESULTS: HCT layering was detected in high resolution equilibrium phase images in one of six healthy subjects, and five of five patients with peripheral vascular occlusive disease (PVOD). Layering occurred only in deep veins that had significantly slower flow and larger diameter (P < 0.001) compared to normal veins. Enhancement patterns observed in vivo were similar to those found in the ex vivo study. CONCLUSION: The HCT layering effect in MR venography has not been previously reported, likely because delayed equilibrium phase venous imaging is not frequently performed. The use of blood pool contrast agents and high resolution equilibrium phase imaging allows intravascular HCT layering to be observed within a 30-60-minute time frame. Several imaging characteristics that distinguish HCT layering from DVT are discussed.

Adult↗

PubMed2006

Sudden unexpected death in infancy and childhood due to undiagnosed neoplasia: an autopsy study.

Sudden unexpected death due to clinically undiagnosed neoplasia in infancy and childhood (SUDNIC) is a rare phenomenon, with only small numbers of cases reported in the literature. In the majority of instances, the tumors involve critical structures within the heart or central nervous system and include gliomas, medulloblastomas, rhabdomyomas, and neoplasms of stromal elements. A 20-year retrospective review of autopsy records from the Hospital for Sick Children, Toronto, was performed (1984-2003, n = 4926), and 7 cases of SUDNIC were identified (0.14%). In addition, 1 case was obtained from the files of the Children's and Women's Health Centre of British Columbia, Vancouver. Diagnoses included 2 cases of acute leukemia (1 myelogenous, 1 lymphoblastic), 2 cases of mediastinal lymphoblastic lymphoma (pre-T cell type), 1 papillary fibroelastoma of the mitral valve prolapsing into and totally occluding the left anterior descending coronary artery, 1 medulloblastoma, 1 Wilms tumor associated with fatal intraperitoneal hemorrhage, and 1 widely disseminated gastric carcinoma. These cases demonstrate that infants and children may have minimal or no symptoms in the presence of significant disease and highlight the need for a thorough autopsy examination in cases of sudden unexpected death in infancy and childhood.

Adolescent↗

PubMed2006

Reovirus variants selected for resistance to ammonium chloride have mutations in viral outer-capsid protein sigma3.

Mammalian reoviruses are internalized into cells by receptor-mediated endocytosis. Within the endocytic compartment, the viral outer capsid undergoes acid-dependent proteolysis resulting in removal of the sigma3 protein and proteolytic cleavage of the mu1/mu1C protein. Ammonium chloride (AC) is a weak base that blocks disassembly of reovirus virions by inhibiting acidification of intracellular vacuoles. To identify domains in reovirus proteins that influence pH-sensitive steps in viral disassembly, we adapted strain type 3 Dearing (T3D) to growth in murine L929 cells treated with AC. In comparison to wild-type (wt) T3D, AC-adapted (ACA-D) variant viruses exhibited increased yields in AC-treated cells. AC resistance of reassortant viruses generated from a cross of wt type 1 Lang and ACA-D variant ACA-D1 segregated with the sigma3-encoding S4 gene. The deduced sigma3 amino acid sequences of six independently derived ACA-D variants contain one or two mutations each, affecting a total of six residues. Four of these mutations, I180T, A246G, I347S, and Y354H, cluster in the virion-distal lobe of sigma3. Linkage of these mutations to AC resistance was confirmed in experiments using reovirus disassembly intermediates recoated with wt or mutant sigma3 proteins. In comparison to wt virions, ACA-D viruses displayed enhanced susceptibility to proteolysis by endocytic protease cathepsin L. Image reconstructions of cryoelectron micrographs of three ACA-D viruses that each contain a single mutation in the virion-distal lobe of sigma3 demonstrated native capsid protein organization and minimal alterations in sigma3 structure. These results suggest that mutations in sigma3 that confer resistance to inhibitors of vacuolar acidification identify a specific domain that regulates proteolytic disassembly.

Adaptation, Physiological↗

PubMed2006

Epinephrine increases mortality after brief asphyxial cardiac arrest in an in vivo rat model.

Epinephrine may be detrimental in cardiac arrest. In this laboratory study we sought to characterize the effect of epinephrine and concomitant calcium channel blockade on postresuscitation myocardial performance after brief asphyxial cardiac arrest. Anesthesized rats were disconnected from mechanical ventilation, resulting in cardiac arrest. Resuscitation was attempted after 1 min with mechanical ventilation, oxygen, chest compressions, and IV medication. In experimental series 1 and 2, animals were allocated to 10 or 30 microg/kg epinephrine or 0.9% saline. In series 3, animals received 30 microg/kg of epinephrine and were randomized to 0.1 mg/kg of verapamil or to 0.9% saline. In series 1 and 3, left ventricular function was assessed using transthoracic echocardiography. In series 2, left atrial pressure was measured. Epinephrine was associated with increased mortality (0/8 [0%] in controls, 4/12 [33.3%] in 10 microg/kg animals, and 16/22 [72.8%] in 30 microg/kg animals; P < 0.05), hypertension (P < 0.001), tachycardia (P = 0.004), early transient left atrial hypertension, and dose-related reduction in left ventricular end diastolic diameter (P < 0.05). Verapamil prevented mortality associated with large-dose epinephrine (0% versus 100%) and attenuated early diastolic dysfunction and postresuscitation hypertension (P = 0.001) without systolic dysfunction. Epinephrine appears to be harmful in the setting of brief cardiac arrest after asphyxia.

Animals↗

PubMed2005

Time-dependent density functional molecular orbital and excited state calculations on bis(porphyrinyl)butadiynes in the monocationic, neutral, monoanionic, and dianionic oxidation states.

We report a theoretical study of the multiple oxidation states (1+, 0, 1-, and 2-) of a meso,meso-linked diporphyrin, namely bis[10,15,20-triphenylporphyrinatozinc(II)-5-yl]butadiyne (4), using Time-Dependent Density Functional Theory (TDDFT). The origin of electronic transitions of singlet excited states is discussed in comparison to experimental spectra for the corresponding oxidation states of the close analogue bis[10,15,20-tris[3',5'-di-tert-butylphenyl]porphyrinatozinc(II)-5-yl]butadiyne (3). The latter were measured in previous work under in situ spectroelectrochemical conditions. Excitation energies and orbital compositions of the excited states were obtained for these large delocalized aromatic radicals, which are unique examples of organic mixed-valence systems. The radical cations and anions of butadiyne-bridged diporphyrins such as 3 display characteristic electronic absorption bands in the near-IR region, which have been successfully predicted with use of these computational methods. The radicals are clearly of the "fully delocalized" or Class III type. The key spectral features of the neutral and dianionic states were also reproduced, although due to the large size of these molecules, quantitative agreement of energies with observations is not as good in the blue end of the visible region. The TDDFT calculations are largely in accord with a previous empirical model for the spectra, which was based simplistically on one-electron transitions among the eight key frontier orbitals of the C4 (1,4-butadiyne) linked diporphyrins.

Journal Article↗

PubMed2005

Photoelectrochemical measurements of a heterosupramolecular system under visible light irradiation.

A photochemical system utilising a modular approach characterised through interpretation of photoelectrochemical measurements is discussed. A photoanode was prepared by the chemisorption of a photosensitiser, cis-bis-(2,2'-bipyridine)-(4,4'-bis-(methyl)phosphonato-2,2'-bipyridine)ruthenium(II) dichloride (RuL2L'2+), to a mixed nanoporous nanocrystalline RuO2:TiO2 thin film, calcined on a fluorine doped SnO2 conducting glass substrate. Similarly, an electron relay molecule, 1-ethyl-1'-(2-phosphonoethyl)-4,4'-bipyridinium dichloride (EVP), was covalently bound to a platinum electroplated nanoporous nanocrystalline TiO2 thin film, and the electrodes connected in a photoelectrocatalytic cell (PCC). Irradiation with lamda > 420 nm gave a measurable photocurrent. Interpretation of the photocurrents obtained from this assembly provides a means for understanding photochemical reactions under low light intensities. Optimised conditions of the electrolyte solution were determined to be pH = 5 and illumination yielded eta = 0.0036% with an apparent quantum yield (AQY)= 1.6%.

Journal Article↗

PubMed2005

Radiofrequency perforation and conventional needle percutaneous transseptal left heart access: pathological features.

Perforating radiofrequency (PRF) energy has been used to obtain percutaneous transseptal left heart access. Contrary to ablative radiofrequency (RF), myocardial tissue responses to PRF thermal injury are incompletely defined. In this study, a newly developed RF catheter system for transseptal left atrial entry was compared with conventional needle puncture. Of 15 piglets having transfemoral cardiac catheterization, 12 had transseptal procedures. Needle punctures (NP) and PRF were followed by acute (1 hr; 3 NP, 3 PRF) and chronic necropsy (1 month; 3 NP, 3 PRF). The remaining three piglets had intentional RF aortic perforation through the atrial roof with necropsy at 1 month. Gross and histopathological effects were examined. Acutely, the gross RF lesion was similar to needle puncture. Histologically, the RF lesions had minimal mural thrombus, an inner zone of thermal injury characterized by grayish cytoplasmic staining (elastic trichrome), and a bubbly transformation of the cytoplasm in innermost cardiomyocytes, partial persistence of cross-striations, and an acute inflammatory reaction. The outer extent of the lesion (< 1 mm) was defined by a halo of contraction band necrosis similar to needle puncture. Acute NP injury showed comparable depth and extent of myocyte necrosis (principally contraction bands) with adjacent tissue hemorrhage and edema. At 1 month, a well-developed densely collagenous scar was present in both aortic and transseptal PRF lesions. The extent of acute RF injury is similar to that seen in conventional NP, but the characteristics of tissue insult are different. Both show well-developed healing at 1 month.

Animals↗

PubMed2005

Medical and economic impact of a respiratory syncytial virus outbreak in a neonatal intensive care unit.

BACKGROUND: Respiratory syncytial virus (RSV) causes frequent nosocomial outbreaks in general pediatric wards but is less commonly reported in neonatal intensive care units (NICUs). We investigated an outbreak of RSV infection in a NICU and its impact on health care delivery, outcomes and costs. METHODS: Retrospective chart review was performed after an RSV outbreak occurred in the NICU. A case was defined as an infant with a nasopharyngeal aspirate positive for RSV by viral culture. Nucleotide sequencing of the isolates was done to determine relatedness. Hospital bills for all RSV culture-positive infants were reviewed. RESULTS: Nine infants (mean age, 34 days; mean birth weight, 1757 g; and mean estimated gestational age 31 weeks and 5 days) were infected with RSV subgroup B during this outbreak. By nucleotide sequencing, the isolates were identical. Clinical manifestations included cough, congestion, increased oxygen requirement, apnea and respiratory failure. The 5 infants requiring intubation had a significantly lower mean birth weight (1301 g versus 2328 g, P = 0.027), mean estimated gestational age (28 weeks and 5 days versus 35 weeks and 2 days, P = 0.014) and mean weight at onset of symptoms (2093 g versus 2989 g, P = 0.049) than the 4 nonintubated infants. More than 1.15 million dollars in hospital charges were attributable to the outbreak. All infants survived. CONCLUSION: Infants in a NICU who develop cough, congestion or apnea should be tested for RSV and other common respiratory viruses during the winter respiratory season. Even in a closed NICU, nosocomial outbreaks of these viruses can occur and have a major effect on healthcare delivery, costs and outcomes.

Cross Infection↗

PubMed2005

Association of drowning and myocarditis in a pediatric population: an autopsy-based study.

CONTEXT: Drowning is a frequent cause of accidental death in childhood, but the association of myocarditis and drowning has only rarely been reported. OBJECTIVE: To report 5 cases of drowning in children with coexistent myocarditis. DESIGN: A retrospective review of autopsy records of patients 0 years to 18 years of age was performed during a 6-year period (1998-2003, total cases reviewed = 1431). RESULTS: Twenty-two drownings were identified, in 14 male and 8 female children. Five patients (23%), 3 female and 2 male children, had coexistent myocarditis. The 5 patients ranged in age from 23 months to 13 years (mean, 7 years 2 months). None of the patients had antecedent symptomatology suggestive of myocarditis. In all patients, the myocarditis was focal mild or moderate, and the inflammatory infiltrate comprised lymphocytes with smaller numbers of neutrophils. All 5 patients had foci of myocyte necrosis. One patient had histologic evidence of myocardial hypertrophy but no evidence of a cardiomyopathy. Microbiologic studies, including culture, immunohistochemistry, polymerase chain reaction, and reverse transcriptase polymerase chain reaction, revealed Mycoplasma pneumoniae DNA in 1 case. CONCLUSIONS: The finding of myocarditis in a significant proportion of drowning victims in this series highlights the importance of a thorough autopsy examination in apparently straightforward cases and has clinicopathologic significance.

Adolescent↗

PubMed2004

Direct electrochemistry of porcine purple acid phosphatase (uteroferrin).

Cyclic voltammetry of the non-heme diiron enzyme porcine purple acid phosphatase (uteroferrin, Uf) has been reported for the first time. Totally reversible one-electron oxidation responses (FeIII-FeII --> FeII-FeIII) are seen both in the absence and in the presence of weak competitive inhibitors phosphate and arsenate, and dissociation constants of these oxoanion complexes formed with uteroferrin in its oxidized state (Uf(o)) have been determined. The effect of pH on the redox potentials has been investigated in the range 3 < pH < 6.5, enabling acid dissociation constants for Uf(o) and its phosphate and arsenate complexes to be calculated.

Acid Phosphatase↗

PubMed2004

Selective inhibition of inward rectifier K+ channels (Kir2.1 or Kir2.2) abolishes protection by ischemic preconditioning in rabbit ventricular cardiomyocytes.

Volume regulatory Cl- channels are key regulators of ischemic preconditioning (IPC). Because Cl- efflux must be balanced by an efflux of cations to maintain cell membrane electroneutrality during volume regulation, we hypothesize that I(K1) channels may play a role in IPC. We subjected cultured cardiomyocytes to 60-minute simulated ischemia (SI) followed by 60-minute of simulated reperfusion (SR) and assessed percent cell death using trypan blue staining. Ischemic preconditioning (10-minute SI/10-minute SR) significantly (P<0.0001) reduced the percent cell death in nontransfected cardiomyocytes [IPC(CM) 18.0+/-2.1% versus control (C(CM)) 48.3+/-1.0%]. IPC protection was not altered by overexpression of the reporter gene (enhanced green fluorescent protein, EGFP). However, overexpression of dominant-negative Kir2.1 or Kir2.2 genes using adenoviruses (AdEGFPKir2.1DN or AdEGFPKir2.2DN) encoding the reporter gene EGFP prevented IPC protection [both IPC(CM)+AdEGFPKir2.1DN 45.8+/-2.3% (mean+/-SEM) and IPC(CM)+AdEGFPKir2.2DN 47.9+/-1.4% versus IPC(CM); P<0.0001] in cultured cardiomyocytes (n=8 hearts). Transfection of cardiomyocytes with AdEGFPKir2.1DN or AdEGFPKir2.2DN did not affect cell death in control (nonpreconditioned) cardiomyocytes (both C(CM)+ AdEGFPKir2.1DN 45.8+/-0.7% and C(CM)+AdEGFPKir2.2DN 46.2+/-1.3% versus C(CM); not statistically significant). Similar effects were observed in both cultured (n=5 hearts) and freshly isolated (n=4 hearts) ventricular cardiomyocytes after I(K1) blockade with 20 micromol/L BaCl2 plus 1 micromol/L nifedipine (to prevent Ba2+ uptake). Nifedipine alone neither protected against ischemic injury nor blocked IPC protection. Our findings establish that I(K1) channels play an important role in IPC protection.

Adenoviridae↗

PubMed2004

Intrauterine pulmonary venous flow and restrictive foramen ovale in fetal hypoplastic left heart syndrome.

OBJECTIVES: We sought to determine whether direct foramen ovale (FO) assessment or pulmonary venous (PV) flow patterns in fetal hypoplastic left heart syndrome (HLHS) correlate with clinical markers of postnatal left atrial (LA) hypertension severity associated with restrictive FO. BACKGROUND: Restrictive FO places a newborn with HLHS at high risk of mortality and morbidity. METHODS: We reviewed the prenatal and postnatal echocardiograms and outcomes of 45 fetuses with variants of HLHS diagnosed since May 1999 to determine whether direct FO assessment or PV flow patterns correlate with clinical LA hypertension after birth. RESULTS: Direct FO assessment in utero showed a poor correlation with postnatal FO size, Pao(2), base excess, and the need for atrial septoplasty (p > 0.05). In 40 fetuses with available PV spectra, three PV flow patterns were observed: 1). continuous forward flow with a small a-wave reversal (velocity time integral [VTI] for reverse/forward flow [VTIR/VTIF ratio <0.18]); 2). continuous forward flow with increased a-wave reversal (VTIR/VTIF ratio >or=0.18); and 3). brief to-and-fro flow. Among 19 live-borns, the postnatal FO diameter was smaller in patients with type B than in those with type A flow (1.6 +/- 1.6 mm and 4.5 +/- 2.1 mm, respectively; p = 0.0015), and all patients with type C flow had an intact atrial septum. All three patients with type C flow were critically ill at birth, requiring emergent atrial septoplasty, and two died after heart transplantation, whereas patients with type A or B flow were clinically stable, with only one postoperative death. CONCLUSIONS: Prenatal PV flow patterns in HLHS identify the fetus at risk of severe LA hypertension at birth.

Atrial Function, Left↗