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PubMed2001

Dynamic changes of atrial septal defect area: new insights by three-dimensional volume-rendered echocardiography with high temporal resolution.

AIMS: The purpose of this study was: (i) to record dynamic changes in the area of atrial septal defects (ASD) during a cardiac cycle, and (ii) to investigate factors which influence ASD dynamics. Implementation of new software modifications allowed the frame rate to be doubled, as compared to usual techniques. METHODS AND RESULTS: Twenty patients were examined using transoesophageal three-dimensional (3D) echocardiography. In 10 patients the 3D dataset was recorded with a frame rate of 25Hz, in another 10 patients with a frame rate of 50Hz. The ASD area was planimetried for each picture and the changes analysed over time. The ASD area showed dynamic changes during the cardiac cycle with an end-systolic maximum and end-diastolic minimum. The influence of the various phases of the cardiac cycle on area changes could be differentiated especially at higher temporal resolution. The relative change in ASD area showed no significant relationship to Q(p)/Q(s)ratio, mean ASD size or heart rate. By contrast, there was a slight inverse correlation to age (r=-0.t45,P <0.05). CONCLUSION: Transoesophageal 3D volume-rendered echocardiography permits quantitative recording of ASD dynamics. The ASD area changes are influenced especially by the various phases of the cardiac cycle.

Adolescent↗
PubMed2001

[Transcatheter closure of atrial septal defects in adults. Practicality and safety of four different closure systems used in 102 patients].

BACKGROUND AND OBJECTIVE: Surgical closure of secundum atrial septal defect (ASD) or patent foramen ovale (PFO) is a procedure with few complications. But this surgical intervention can nowadays be avoided by transcatheter insertion of occluding devices. Such interventional methods must be judged against the results of surgical procedures. This report from one center presents the practicability and safety of different transcatheter occluder systems. PATIENTS AND METHODS: Transcatheter occlusion was undertaken in 102 patients (40 females, 62 males, aged between 17 and 76 years [median age 45]) with either an ASD (41pts.) or a PFO (60 pts.) or with both, in one patient. Four different systems were used: ASDOS (for ASD and PFO), PFO-STAR (for PFO), Amplatzer Septal Occluder (for ASD) or Amplatzer PFO Occluder (for PFO). Follow-up, including transoesophageal echocardiography took place 48 hours, 4 weeks, 6 months and 1 year after the interventional occluder placement. RESULTS: An occluder was successfully placed in the ASD or PFO in 99 of the 102 patients. In three patients the occluder ( ASDOS ASD) could not be correctly ancchored in the defect. In two other patients the same device was subsequently removed surgically because of mispositioning or a large resiudal shunt. Occluder-associated problems were: mild (41%) or extensive (11%) thrombus formation on the occluder without early embolization, residual shunt at one year (ASD 16%, PFO 29%); minor displacement (10%) or broken umbrella strut (6%) of no clinical relevance. One patient required emergency surgical intervention on the day of the transcatheter placement (PFO-STAR) because of pricardial tamponade. Primary complete occlusion was achieved in 71%. There was no case of cerebral emboli. CONCLUSION: Transcatheter occlusion of ASD and/or PFO is a reliable and safe procedure. Regarding peri- and/or postinterventional complications, primary results and practicability, the Amplatzer septal occluder and Amplatzer PFO occluder are particularly advantageous.

Adolescent↗
PubMed2000

Increased discrimination of "false memories" in autism spectrum disorder.

Individuals with autism spectrum disorder (ASD) have impaired ability to use context, which may manifest as alterations of relatedness within the semantic network. However, impairment in context use may be more difficult to detect in high-functioning adults with ASD. To test context use in this population, we examined the influence of context on memory by using the "false memory" test. In the false memory task, lists of words were presented to high-functioning subjects with ASD and matched controls. Each list consists of words highly related to an index word not on the list. Subjects are then given a recognition test. Positive responses to the index words represent false memories. We found that individuals with ASD are able to discriminate false memory items from true items significantly better than are control subjects. Memory in patients with ASD may be more accurate than in normal individuals under certain conditions. These results also suggest that semantic representations comprise a less distributed network in high-functioning adults with ASD. Furthermore, these results may be related to the unusually high memory capacities found in some individuals with ASD. Research directed at defining the range of tasks performed superiorly by high-functioning individuals with ASD will be important for optimal vocational rehabilitation.

Adult↗
PubMed2005

Autism spectrum traits in children with mood and anxiety disorders.

The autism spectrum disorders (ASDs) can present with symptoms commonly found in mood and anxiety disorders. The Social Communication Questionnaire (SCQ), Children's Communication Checklist (CCC-2), and the Social Reciprocity Scale (SRS) were used to screen children in a mood disorders research clinic setting for symptoms of ASD. Ninety-three patients (mean age, 12.7 +/- 2.8 years; percent male, 63%) completed at least one scale, and 50 children completed all three. The prevalence of those screening positive for a possible ASD on one instrument was 62% and on all three measures was 8%. Fifty-seven percent (n = 21/37; odds ratio, 4.59 [95% confidence interval (CI) = 1.40-15.11]) of those scoring in the "ASD-likely" range on the SRS scored in that range on the CCC-2. Only 16% (n = 6/37; odds ratio, not significant (NS)) of those scoring in the ASD-likely range on the SRS, and 14% (n = 5/37; odds ratio, NS) of those scoring in the ASD-likely range on the CCC-2, scored similarly on the SCQ. These results demonstrate a need to develop valid and reliable instruments to screen for ASDs in children presenting outside of ASD clinics.

Adolescent↗
PubMed1994

Surveillance of AIDS-defining conditions in the United States. Adult/Adolescent Spectrum of HIV Disease Project Group.

OBJECTIVE: To examine the reporting of AIDS-defining illnesses using two national surveillance systems. METHODS: Comparison of AIDS indicator diseases reported to the national AIDS reporting system (ARS) for AIDS cases diagnosed from January 1990-December 1992 among individuals aged > 13 years in 10 metropolitan areas, with that observed in the Adult/Adolescent Spectrum of HIV Disease (ASD) project, a surveillance project that monitors the clinical diagnoses of HIV-infected individuals receiving medical care. RESULTS: In the 10 metropolitan areas, 39,265 individuals with AIDS were reported to ARS, and 5969 with AIDS had medical record reviews as part of ASD. At initial AIDS diagnosis, the number of indicator diseases reported to ARS was almost identical to the number observed in ASD (mean number of diagnoses, ARS 1.3; ASD 1.2). However, ASD recorded a greater number of diagnoses over time than ARS (mean number of indicator diagnoses > 12 months after initial diagnosis, ASD 2.3; ARS 1.4). Conditions that typically occur late in the course of AIDS such as Mycobacterium avium infection and cytomegalovirus disease, were more frequently recorded by ASD than by ARS. CONCLUSION: ARS provides complete, population-based information on the frequency of AIDS-defining conditions at initial diagnosis. However, specialized surveillance projects such as ASD are needed to accurately describe subsequent AIDS-defining conditions.

AIDS-Related Opportunistic Infections↗
PubMed2006

Frequency of gastrointestinal symptoms in children with autistic spectrum disorders and association with family history of autoimmune disease.

This is a cross-sectional study that compares lifetime prevalence of gastrointestinal (GI) symptoms in children with autistic spectrum disorders (ASDs) and children with typical development and with other developmental disabilities (DDs) and examines the association of GI symptoms with a family history of autoimmune disease. A structured interview was performed in 50 children with ASD and 2 control groups matched for age, sex, and ethnicity-50 with typical development and 50 with other DDs. Seventy-four percent were boys with a mean age of 7.6 years (SD, +/-3.6). A history of GI symptoms was elicited in 70% of children with ASD compared with 28% of children with typical development (p <.001) and 42% of children with DD (p =.03). Abnormal stool pattern was more common in children with ASD (18%) than controls (typical development: 4%, p =.039; DD: 2%, p =.021). Food selectivity was also higher in children with ASD (60%) compared with those with typical development (22%, p =.001) and DD (36%, p =.023). Family history of autoimmune disease was reported in 38% of the ASD group and 34% of controls and was not associated with a differential rate of GI symptoms. In the multivariate analysis, autism (adjusted odds ratio (OR), 3.8; 95% confidence interval (CI), 1.7-11.2) and food selectivity (adjusted OR, 4.1; 95% CI, 1.8-9.1) were associated with GI symptoms. Children with ASD have a higher rate of GI symptoms than children with either typical development or other DDs. In this study, there was no association between a family history of autoimmune disease and GI symptoms in children with ASD.

Adolescent↗
PubMed2004

Usefulness of live three-dimensional transthoracic echocardiography in the characterization of atrial septal defects in adults.

In this report we present 12 adult patients in whom surgical or percutaneous intervention was considered for repair of atrial septal defect (ASD). Location, size, and surrounding atrial anatomy of the ASD were assessed prior to intervention in all patients with standard and live three-dimensional transthoracic echocardiography (3D TTE). In the four patients in whom intraoperative three-dimensional transesophageal echocardiographic reconstruction (3D TEE) was done, 3D TTE measurements of maximum dimension, maximum circumference, and maximum area of ASD agreed well with 3D TEE. In the seven patients who underwent transcatheter closure device insertion, live 3D TTE measurements of maximum dimension, maximum circumference, and maximum area of ASD agreed well with the sizing balloon. Additionally, since the sizing balloon measures a stretched diameter and area, a live 3D TTE stretched ASD diameter and area (derived from the actual live 3D TTE maximum circumference) were calculated and demonstrated improved agreement with the sizing balloon measurements. In all patients, > or =5 mm of atrial tissue was visualized surrounding the ASD. Further, with the addition of contrast enhancement, characterization of a small patent foramen ovale (<5 mm) was possible in one patient. Live 3D TTE accurately defined ASD location, size, and surrounding atrial anatomy in all patients studied by us. ASD characterization by live 3D TTE agreed well with 3D TEE and sizing balloon measurements.

Adolescent↗
PubMed2005

The role of the medial temporal lobe in autistic spectrum disorders.

The neural basis of autistic spectrum disorders (ASDs) is poorly understood. Studies of mnemonic function in ASD suggest a profile of impaired episodic memory with relative preservation of semantic memory (at least in high-functioning individuals). Such a pattern is consistent with developmental hippocampal abnormality. However, imaging evidence for abnormality of the hippocampal formation in ASD is inconsistent. These inconsistencies led us to examine the memory profile of children with ASD and the relationship to structural abnormalities. A cohort of high-functioning individuals with ASD and matched controls completed a comprehensive neuropsychological memory battery and underwent magnetic resonance imaging for the purpose of voxel-based morphometric analyses. Correlations between cognitive/behavioural test scores and quantified results of brain scans were also carried out to further examine the role of the medial temporal lobe in ASD. A selective deficit in episodic memory with relative preservation of semantic memory was found. Voxel-based morphometry revealed bilateral abnormalities in several areas implicated in ASD including the hippocampal formation. A significant correlation was found between parental ratings reflecting autistic symptomatology and the measure of grey matter density in the junction area involving the amygdala, hippocampus and entorhinal cortex. The data reveal a pattern of impaired and relatively preserved mnemonic function that is consistent with a hippocampal abnormality of developmental origin. The structural imaging data highlight abnormalities in several brain regions previously implicated in ASD, including the medial temporal lobes.

Adolescent↗
PubMed2005

The prevalence of autistic spectrum disorder in children surveyed in a tertiary care epilepsy clinic.

UNLABELLED: It is well documented that children with autistic spectrum disorder (ASD) have an increased prevalence of seizures; however, studies have not been done to evaluate the prevalence of ASD in children with epilepsy. This comorbidity is important to define as early diagnosis and intervention in some children with ASD has been shown to improve outcome. METHOD: Children with epilepsy seen in a tertiary care epilepsy clinic were evaluated using validated autism screening questionnaires (ASQ). In addition, questions about sleep-related disorders, behavior, seizure characteristics, antiepileptic agents, and body mass index (BMI) were requested. An attempt was then made to determine if there was a correlation between the factors identified and ASD. RESULTS: Of the 107 questionnaires returned, 97 ASQ's were properly completed and used in this study. Approximately 32% of children fit the ASQ criteria for having ASD. Most children had not been previously diagnosed. Worst behavior and daytime sleepiness was seen in those at greater risk (p < 0.01). Seizures also occurred earlier (approximately 2 years) in children at risk of having ASD. CONCLUSION: Though confirmatory diagnostic evaluations are needed, this questionnaire-based study suggests that children with epilepsy are at greater risk of having ASD, and illustrates the need for more clinical vigilance. Behavioral difficulties and daytime sleepiness identified in these children could potentially affect their ability to learn. It is of interest that the age of seizure onset identified in those at greater risk corresponds with the approximate age of regression identified in some children with ASD.

Adolescent↗
PubMed2001

Analysis of P wave and P dispersion in children with secundum atrial septal defect.

BACKGROUND: P maximum and P dispersion are evaluated as predictors of paroxysmal atrial fibrillation in adults. In this study, these variables are being investigated in children with secundum ASD in comparison with that of normal controls and in relation to size of ASD and the presence or absence of atrial dilation. METHODS: Ninety-four children with isolated secundum ASD (33 boys, 60 girls; mean +/- SD age at diagnosis 2.9 +/- 4.1 years) and 65 age-matched controls (mean +/- SD age 4.2 +/- 4.2 years) were evaluated. Resting 12-lead ECG was used to measure P waves from which P maximum and P dispersion (difference between maximum and minimum P-wave duration) were derived. ASD children were arbitrarily subgrouped according to ASD sizes (small: 1-3 mm, moderate: 4-7 mm, large: > or = 8 mm). The presence of right atrial dilation was noted from echocardiography. RESULTS: Children with ASD had significantly longer mean P dispersion compared to controls (P dispersion: 30.2 +/- 11.1 vs 26.4 +/- 6.6 ms, P = 0.008). Mean P maximum and P dispersion were significantly prolonged with increasing ASD size (P < 0.001). Children with right atrial dilation had significantly longer P maximum (102.3 +/- 15.2 vs 82.8 +/- 13.4 ms, P < 0.001) and larger P dispersion (36.1 +/- 12.5 vs 27.6 +/- 9.4 ms, P = 0.003) compared to those without right atrial dilation. CONCLUSION: Prolonged atrial conduction time and inhomogeneity of atrial conduction may possibly be present in children with moderate to large sized ASD and in those with atrial dilation.

Analysis of Variance↗
PubMed2004

Maximum p wave duration and p wave dispersion in adult patients with secundum atrial septal defect: the impact of surgical repair.

BACKGROUND: Patients with atrial septal defect (ASD) have an increased risk for atrial fibrillation (AF). Previously it was shown that maximum P wave duration and P wave dispersion in 12-lead surface electrocardiograms are significantly increased in individuals with a history of paroxysmal AF. We studied P maximum and P dispersion in adult patients with ASD during normal sinus rhythm. In addition, the impact of surgical closure of ASD on these variables within 1 year after surgery was evaluated. METHODS: Thirty-four patients (21 women, 13 men; mean age: 35 +/- 11 years) operated on for ostium secundum type ASD and 24 age-matched healthy subjects (13 women, 11 men; mean age: 37 +/- 10 years) were investigated. P maximum, P minimum, and P dispersion (maximum - minimum P wave duration) were measured from the 12-lead surface electrocardiography. RESULTS: P maximum was found to be significantly longer in patients with ASD as compared to controls (115.2 +/- 9 vs 99.3 +/- 14 ms; P < 0.0001). In addition, P dispersion of the patients was significantly higher than controls (37 +/- 9 vs 29.8 +/- 10 ms; P = 0.003). P minimum was not different between the two groups (P = 0.074). After surgical repair of ASD, 10 patients (29%) experienced one or more episodes of paroxysmal AF. Patients with postoperative AF were older (45 +/- 6 vs 30 +/- 10 years; P = 0.001), and had a higher preoperative pulmonary artery peak systolic pressure as compared to those without postoperative AF (51 +/- 11 vs 31 +/- 9 mmHg; P < 0.0001). No significant difference in the pulmonary-to-systemic flow ratio was observed preoperatively between the two groups (P = 0.56). P maximum and P dispersion were significantly higher in patients with postoperative paroxysmal AF at baseline and at postoperative first month, sixth month, and first year as compared to those without it (for P maximum P = 0.027, P = 0.014, P = 0.001, P < 0.0001, respectively; for P dispersion P = 0.037, P = 0.026, P = 0.001, P < 0.0001, respectively). In addition, in patients with postoperative AF, no significant changes were detected in both of these P wave indices during postoperative follow-up. However, in the other group, P maximum and P dispersion were found to be significantly decreased at postoperative 6 months and 1 year as compared to baseline. P minimum was similar throughout the postoperative follow-up as compared to baseline in both groups. CONCLUSIONS: Mechanical and electrical changes in atrial myocardium may cause greater P maximum and P dispersion in patients with ASD. Surgical closure of the ASD can regress these pathological changes of atrial myocardium with a result in decreased P maximum and P dispersion. However, higher P maximum and P dispersion at baseline, which have not decreased after surgery, may be associated with postoperative paroxysmal AF, especially for older patients.

Adrenergic beta-Antagonists↗
PubMed2005

Cardiac troponin I release after transcatheter atrial septal defect closure depends on occluder size but not on patient's age.

OBJECTIVE: To examine whether transcatheter closure of secundum atrial septal defect (ASD) with the Amplatzer septal occluder leads to more myocardial injury in children than in adults. DESIGN: In a prospective study with children and adults cardiac troponin I (cTnI) serum concentrations were determined by immunoassay (AxSYM, Abbott Laboratories) before, during, and up to 20 months after surgical or transcatheter ASD closure. PATIENTS: Four groups of patients were studied: transcatheter ASD closure (group 1: 22 children, age range 3.26-14.7 years; group 2: 22 adults, 18.0-67.3 years), surgical ASD closure (group 3: 18 children, 3.12-13.5 years), and diagnostic catheterisation (group 4: 12 children, 2.68-15.0 years). RESULTS: cTnI concentrations were significantly increased after occluder implantation with higher serum concentrations in children than in adults (immediately after implantation: group 1, 3.2 (4.4) microg/l; group 2, 1.1 (4.2) microg/l; four hours after implantation: group 1, 4.8 (5.0) microg/l; group 2, 1.7 (2.3) microg/l; both p < 0.01, group 1 v group 2; one day after implantation: group 1, 3.0 (5.7) microg/l; group 2, 2.2 (5.2) microg/l) but were less than 20% of those after surgical ASD closure (group 3; p < 0.001) where the highest cTnI concentration was found (37.1 (26.3) microg/l). Diagnostic catheterisation (group 4) was not associated with detectable cTnI increase. From the cTnI concentrations the total amount of cTnI released after ASD closure was estimated for each patient. This was dependent on the size of the occluder (p < 0.05) but not on the patient's age or procedural duration. CONCLUSION: In regard to interventional ASD closure our data do not provide evidence that the child's myocardium is more vulnerable. Transcatheter ASD closure induces minor myocardial lesion, the extent of which depends on the size of the Amplatzer septal occluder but is irrespective of the patient's age.

Adolescent↗
PubMed2002

Innate immunity associated with inflammatory responses and cytokine production against common dietary proteins in patients with autism spectrum disorder.

OBJECTIVES: Children with autism spectrum disorder (ASD) frequently reveal various gastrointestinal (GI) symptoms that may resolve with an elimination diet along with apparent improvement of some of the behavioral symptoms. Evidence suggests that ASD may be accompanied by aberrant (inflammatory) innate immune responses. This may predispose ASD children to sensitization to common dietary proteins (DP), leading to GI inflammation and aggravation of some behavioral symptoms. METHODS: We measured IFN-gamma, IL-5, and TNF-alpha production against representative DPs [gliadin, cow's milk protein (CMP), and soy] by peripheral blood mononuclear cells (PBMCs) from ASD and control children [those with DP intolerance (DPI), ASD siblings, and healthy unrelated children]. We evaluated the results in association with proinflammatory and counter-regulatory cytokine production with endotoxin (LPS), a microbial product of intestinal flora and a surrogate stimulant for innate immune responses. RESULTS: ASD PBMCs produced elevated IFN-gamma and TNF-alpha, but not IL-5 with common DPs at high frequency as observed in DPI PBMCs. ASD PBMCs revealed increased proinflammatory cytokine responses with LPS at high frequency with positive correlation between proinflammatory cytokine production with LPS and IFN-gamma and TNF-alpha production against DPs. Such correlation was less evident in DPI PBMCs. CONCLUSION: Immune reactivity to DPs may be associated with apparent DPI and GI inflammation in ASD children that may be partly associated with aberrant innate immune response against endotoxin, a product of the gut bacteria.

Adolescent↗
PubMed2003

Magnetic resonance image-guided transcatheter closure of atrial septal defects.

BACKGROUND: Recent developments in cardiac MRI have extended the potential spectrum of diagnostic and interventional applications. The purpose of this study was to test the ability of MRI to perform transcatheter closures of secundum type atrial septal defects (ASD) and to assess ASD size and changes in right cardiac chamber volumes in the same investigation. METHODS AND RESULTS: In 7 domestic swine (body weight, 38+/-13 kg), an ASD (Q(p):Q(s)=1.7+/-0.2) was created percutaneously by balloon dilation of the fossa ovalis. The ASD was imaged and sized by both conventional radiography and MRI. High-resolution MRI of the ASD diameters correlated well with postmortem examination (r=0.97). Under real-time MR fluoroscopy, the introducer sheath was tracked toward the left atrium with the use of novel miniature MR guide wires. The defect was then closed with an Amplatzer Septal Occluder. In all animals, it was possible to track and interactively control the position of the guide wire within the vessels and the heart, including the successful deployment of the Amplatzer Septal Occluder. Right atrial and ventricular volumes were calculated before and after the intervention by using cine-MRI. Both volumes were found to be significantly reduced after ASD closure (P<0.005). CONCLUSIONS: These in vivo studies demonstrate that catheter tracking and ASD device closure can be performed under real-time MRI guidance with the use of intravascular antenna guide wires. High-resolution imaging allows accurate determination of ASD size before the intervention, and immediate treatment effects such as changes in right cardiac volumes can also be measured.

Animals↗
PubMed2005

Androgen conversion in osteoarthritis and rheumatoid arthritis synoviocytes--androstenedione and testosterone inhibit estrogen formation and favor production of more potent 5alpha-reduced androgens.

In synovial cells of patients with osteoarthritis (OA) and rheumatoid arthritis (RA), conversion products of major anti-inflammatory androgens are as yet unknown but may be proinflammatory. Therefore, therapy with androgens in RA could be a problem. This study was carried out in order to compare conversion products of androgens in RA and OA synoviocytes. In 26 OA and 24 RA patients, androgen conversion in synovial cells was investigated using radiolabeled substrates and analysis by thin-layer chromatography and HPLC. Aromatase expression was studied by immunohistochemistry. Dehydroepiandrosterone (DHEA) was converted into androstenediol, androstenedione (ASD), 16alphaOH-DHEA, 7alphaOH-DHEA, testosterone, estrone (E1), estradiol (E2), estriol (E3), and 16alphaOH-testosterone (similar in OA and RA). Surprisingly, levels of E2, E3, and 16alpha-hydroxylated steroids were as high as levels of testosterone. In RA and OA, 5alpha-dihydrotestosterone increased conversion of DHEA into testosterone but not into estrogens. The second androgen, ASD, was converted into 5alpha-dihydro-ASD, testosterone, and negligible amounts of E1, E2, E3, or 16alphaOH-testosterone. 5alpha-dihydro-ASD levels were higher in RA than OA. The third androgen, testosterone, was converted into ASD, 5alpha-dihydro-ASD, 5alpha-dihydrotestosterone, and negligible quantities of E1 and E2. 5alpha-dihydrotestosterone was higher in RA than OA. ASD and testosterone nearly completely blocked aromatization of androgens. In addition, density of aromatase-positive cells and concentration of released E2, E3, and free testosterone from superfused synovial tissue was similar in RA and OA but estrogens were markedly higher than free testosterone. In conclusion, ASD and testosterone might be favorable anti-inflammatory compounds because they decrease aromatization and increase anti-inflammatory 5alpha-reduced androgens. In contrast, DHEA did not block aromatization but yielded high levels of estrogens and proproliferative 16alpha-hydroxylated steroids. Androgens were differentially converted to pro- and anti-inflammatory steroid hormones via diverse pathways.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗
PubMed1993

Functional obstruction of an antisiphon device by raised tissue capsule pressure.

The proper function of an antisiphon device (ASD) requires that it be exposed externally to atmospheric pressure and that its mobile membrane be free to move. A 4-year-old boy who had an ASD placed for postshunt subdural hematomas presented with functional obstruction of the ASD-symptomatic ventriculomegaly despite evidence of patency of the shunt system by radionuclide flow study. At surgery, the distal shunt system including the ASD was infused with normal saline before and after surgical exposure of the device. The pressures required to maintain a flow rate of 5 ml/h and 50 ml/h were 27 mm Hg and 30 mm Hg, respectively. After surgical exposure, these pressures fell to 0 mm Hg and 5 mm Hg, respectively, for the same infusion rates. Surgical exposure removes the effects of the tissue capsule, including the overlying skin and a collagenous sheath, restoring the external pressure to atmospheric pressure. Functional obstruction of ASDs occurs because of raised ambient pressure from the tissue capsule acting to depress the mobile membrane of the ASD, increasing its resistance to flow. This case confirms previously reported effects of subcutaneous implantation of ASDs in experimental animals and is the probable explanation for reported functional obstruction of ASDs in other patients.

Astrocytoma↗
PubMed1998

Evaluation of right ventricular systolic pressure during incremental exercise by Doppler echocardiography in adults with atrial septal defect.

STUDY OBJECTIVES: Pulmonary hypertension is the most important complication in patients with atrial septal defect (ASD), but its role in limiting exercise has not been examined. This study sought to evaluate exercise performance in adults with ASD and determine the contribution of elevated pulmonary artery pressure in limiting exercise capacity. DESIGN: We used Doppler echocardiography during exercise in 10 adults (aged 34 to 70 years) with isolated ASD (New York Heart Association class I, II) and an equal number of matched control subjects. Incremental exercise was performed on an electrically braked upright cycle ergometer. Expired gases and VE were measured breath-by-breath. Two-dimensional and Doppler echocardiographic images were obtained at rest prior to exercise to determine ASD size, stroke volume (SV), shunt ratio (Qp:Qs), right ventricular outflow tract (RVOT) size, and right ventricular systolic pressure at rest (RVSPr). Doppler echocardiography was repeated at peak exercise to measure right ventricular systolic pressure during exercise (RVSPex). RESULTS: Resting echocardiography revealed that RVOT was larger (21+/-4 vs 35+/-8 mm, mean+/-SD; p=0.0009) and RVSPr tended to be higher (17+/-8 vs 31+/-8 mm Hg; p=0.08) in ASD; however, left ventricular SV was not different (64+/-23 vs 58+/-23 mL; p>0.05), compared with control subjects. Despite normal resting left ventricular function, ASD patients had a significant reduction in maximum oxygen uptake (VO2max) (22.9+/-5.4 vs 17.3+/-4.2 mL/kg/min; p=0.005). RVSPex was higher (19+/-8 vs 51+/-10 mm Hg; p=0.001) and the mean RVSP-VO2 slope (1+/-2 vs 18+/-3 mm Hg/L/min; p=0.003) and intercept (17+/-4 vs 27+/-4 mm Hg; p=0.05) were higher in the ASD group. VO2max correlated inversely with both RVSPr (r=-0.69; p=0.007) and RVSPex (r=-0.67; p=0.01). CONCLUSION: These findings suggest that adults with ASD have reduced exercise performance, which may be associated with an abnormal increase in pulmonary artery pressure during exercise.

Adult↗
PubMed1995

The first heart sound in atrial septal defect with reference to atrioventricular valve motion and hemodynamics.

To clarify the characteristics of the first heart sound in atrial septal defect (ASD) and its pathophysiological basis, 17 patients with ASD associated with incomplete right bundle branch block (IRBBB) and 7 with isolated IRBBB were studied using phonoechocardiography and Doppler echocardiography. Fifteen of the 17 ASD patients also were studied following surgical closure of the defect. Indices were compared among the preoperative ASD, postoperative ASD, and IRBBB groups including: P-Q intervals, loudness of the mitral and tricuspid component of the first heart sound (IM, IT), end-diastolic closing excursions of the mitral and tricuspid valves (Mx, Tx), and mitral and tricuspid inflow velocities during early diastole and atrial contraction. There were no significant differences in the P-Q intervals among these 3 groups. IM was attenuated, and IT was accentuated in ASD compared with IRBBB. Postoperatively, IM was augmented in all but 1 patient and IT was attenuated in all patients. Mx was significantly smaller, and Tx was significantly larger in ASD than in IRBBB. Postoperatively, Mx was significantly increased and Tx was significantly reduced; the maximal mitral inflow velocity during atrial contraction was increased while the maximal tricuspid inflow velocity was significantly reduced. Thus, the first heart sound in ASD is characterized by an attenuated mitral component and an accentuated tricuspid component. Hemodynamic alterations and consequent changes in closing energies of the atrioventricular valves probably account for these features.

Adolescent↗