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Biomedical subjects

H Baumgartner

Publications and source records attributed to H Baumgartner.

At least 19 recordsLinked to original sources
PubMed2006

Structural properties of screened Coulomb balls.

Small three-dimensional strongly coupled charged particles in a spherical confinement potential arrange themselves in a nested shell structure. By means of experiments, computer simulations, and theoretical analysis, the sensitivity of their structural properties to the type of interparticle forces is explored. While the normalized shell radii are found to be independent of shielding, the shell occupation numbers are sensitive to screening and are quantitatively explained by an isotropic Yukawa model.

Journal Article↗
PubMed2006

[Aortic stenosis].

Explore the source record for details and available documents.

Aortic Valve Stenosis↗
PubMed2004

Cerebral microembolism during transcatheter closure of patent foramen ovale.

BACKGROUND: Although transcatheter closure of patent foramen ovale (PFO) and atrial septal defect (ASD) has become a commonly performed intervention, the incidence of cerebral embolism with or without neurological deficits during such procedures has not been studied. METHODS: We monitored the middle cerebral artery in two different depths (48 mm and 53 mm) by continuous transcranial Doppler ultrasound during transcatheter PFO closure in 35 consecutive patients (F/M 20/15, mean age 47 +/- 11 years) and during ASD closure in 8 patients (F/M 7/1, mean age 45 +/- 5 years). All automatically detected high intensity transient signals (HITS) were manually reviewed to eliminate artifacts. RESULTS: HITS were detected in 33 of 35 patients (96%) with a median rate of 8 (interquartile range 4-19, range 2-29) HITS. The highest rates were observed when the septum was crossed with the guide wire (median 2; IQR 0-12; range 0-25) and when the left atrial disc was deployed (median 2; IQR 1-4; range 0-13). Despite this high rate of cerebral microembolism no clinically apparent neurological or neuropsychological deficit was observed. CONCLUSIONS: Silent cerebral embolism frequently occurs during transcatheter PFO and ASD closure. The peak of HITS at the time of crossing the septum with the guide wire may support the hypothesis that cerebral emboli in patients with PFO may originate from the septum itself. This may represent an alternative mechanism to the generally assumed paradoxical embolism.

Adult↗
PubMed2001

[Ductus arteriosus apertus as the cause of recurrent nerve paralysis. A case report].

There are various reasons for paralysis of the vocal folds, which consequently imposes great demands on differential diagnostics. Angiocardiopathies are regarded as very rare cases of etiopathogenesis. In the present case, a persistent arterial duct could be identified as the reason for the paralysis of the left recurrent nerve of a 59-year-old female patient. The necessity of interdisciplinary diagnostics going beyond the field of otorhinolaryngology is emphasized, especially in cases of a paralysis of the recurrent nerve.

Diagnosis, Differential↗
PubMed2001

Reproductive issues in adults with congenital heart disease: arrhythmias during pregnancy: importance, diagnosis and therapy.

Even in healthy women, increased ectopic activity is commonly seen during pregnancy. Congenital heart defects--whether nonoperated or operated--are, in general, associated with an increased risk of arrhythmias to a greater or lesser extent. During pregnancy, congenital heart disease patients are at increased risk of presenting first time with a symptomatic arrhythmia or, if previously diagnosed, the risk of recurrence of their arrhythmia is increased. Antiarrhythmic therapy should in general be restricted to the presence of intolerable symptoms, hemodynamic compromise or threat to the fetus and to patients in whom the arrhythmia may be life-threatening. The risk/benefit ratio must be considered for both the mother and the fetus. Considerations include the stage of pregnancy as well as possible effects of therapy on labor, delivery, and lactation. Nearly all of the presently available antiarrhythmic drugs are classified as Category C drugs in pregnancy. Thus, we rely on observational reports. Safety data are discussed for various drugs, and recommendations for the treatment of various arrhythmias are presented in this review.

Anti-Arrhythmia Agents↗
PubMed2001

Long-term treatment of pulmonary hypertension with aerosolized iloprost.

Pulmonary arterial hypertension (PAH), defined as elevated pulmonary arterial pressure and pulmonary vascular resistance, is an end-point of a variety of conditions. The only therapy that has been shown to improve both quality of life and survival is intravenous prostacyclin (prostaglandin I2 (PGI2), epoprostenol). The effect of long-term aerosolized iloprost (Ilomedin, Schering, Berlin, Germany and Vienna, Austria), a stable prostacyclin analogue and potent vasodilator, on haemodynamics and functional status was investigated in 12 patients with severe pulmonary hypertension. Haemodynamic measurements and vasodilator testing by right heart catheterization were performed prior to and after long-term iloprost inhalation therapy. Haemodynamic improvement or increased exercise tolerance was not observed in any of the patients. After a mean+/-SD treatment period of 10+/-5 months, mean+/-SD pulmonary vascular resistance had increased from 11+/-3 Wood Units (mmHg.L(-1).min) to 13+/-4 Wood Units, with unchanged arterial oxygen saturation (92+/-4%, versus 91+/-4%). Within the study period, three patients went into right heart failure and had to be placed on intravenous epoprostenol. The authors conclude that inhaled iloprost in addition to conventional therapy in the presently recommended dose of 100 microg.day(-1) delivered in 8-10 2 h portions, is not an efficient vasodilator therapy in severe pulmonary hypertension. It remains to be shown whether dose increases and/or combination protocols will be effective, or whether inhalation of iloprost may be safe for selected cases of pulmonary hypertension.

Administration, Inhalation↗
PubMed2000

Predictors of outcome in severe, asymptomatic aortic stenosis.

BACKGROUND: Whether to perform valve replacement in patients with asymptomatic but severe aortic stenosis is controversial. Therefore, we studied the natural history of this condition to identify predictors of outcome. METHODS: During 1994, we identified 128 consecutive patients with asymptomatic, severe aortic stenosis (59 women and 69 men; mean [+/-SD] age, 60+/-18 years; aortic-jet velocity, 5.0+/-0.6 m per second). The patients were prospectively followed until 1998. RESULTS: Follow-up information was available for 126 patients (98 percent) for a mean of 22+/-18 months. Event-free survival, with the end point defined as death (8 patients) or valve replacement necessitated by the development of symptoms (59 patients), was 67+/-5 percent at one year, 56+/-5 percent at two years, and 33+/-5 percent at four years. Five of the six deaths from cardiac disease were preceded by symptoms. According to multivariate analysis, only the extent of aortic-valve calcification was an independent predictor of outcome, whereas age, sex, and the presence or absence of coronary artery disease, hypertension, diabetes, and hypercholesterolemia were not. Event-free survival for patients with no or mild valvular calcification was 92+/-5 percent at one year, 84+/-8 percent at two years, and 75+/-9 percent at four years, as compared with 60+/-6 percent, 47+/-6 percent, and 20+/-5 percent, respectively, for those with moderate or severe calcification. The rate of progression of stenosis, as reflected by the aortic-jet velocity, was significantly higher in patients who had cardiac events (0.45+/-0.38 m per second per year) than those who did not have cardiac events (0.14+/-0.18 m per second per year, P<0.001), and the rate of progression of stenosis provided useful prognostic information. Of the patients with moderately or severely calcified aortic valves whose aortic-jet velocity increased by 0.3 m per second or more within one year, 79 percent underwent surgery or died within two years of the observed increase. CONCLUSIONS: In asymptomatic patients with aortic stenosis, it appears to be relatively safe to delay surgery until symptoms develop. However, outcomes vary widely. The presence of moderate or severe valvular calcification, together with a rapid increase in aortic-jet velocity, identifies patients with a very poor prognosis. These patients should be considered for early valve replacement rather than have surgery delayed until symptoms develop.

Adult↗
PubMed2000

Right ventricle lipoma with pseudoaneurysmatic appearance.

The case of a 78-year-old female patient, with a large lipoma (13 x 17 x 10 cm) of the right ventricle, appearing pseudoaneurysmatic, is presented. Radical resection left a considerable right ventricle wall and interventricular septum defect which was reconstructed with a bovine pericardium patch.

Aged↗
PubMed2000

Long-term outcome in congenitally corrected transposition of the great arteries: a multi-institutional study.

OBJECTIVES: The purpose of this study was to determine long-term outcome in adults with congenitally corrected transposition of the great arteries (CCTGA), with particular emphasis on systemic ventricular dysfunction and congestive heart failure (CHF). BACKGROUND: Patients with CCTGA have the anatomical right ventricle as their systemic pumping chamber, with ventricular dysfunction and CHF being relatively common in older adults. METHODS: Retrospective analysis of records of 182 patients from 19 institutions were reviewed to determine current status and possible risk factors for systemic ventricular dysfunction and CHF. Factors considered included age, gender, associated cardiac defects, operative history, heart block, arrhythmias and tricuspid (i.e., systemic atrioventricular) regurgitation (TR). RESULTS: Both CHF and systemic ventricular dysfunction were common in groups with or without associated cardiac lesions. By age 45, 67% of patients with associated lesions had CHF, and 25% of patients without associated lesions had this complication. The rates of systemic ventricular dysfunction and CHF were higher with increasing age, the presence of significant associated cardiac lesions, history of arrhythmia, pacemaker implantation, prior surgery of any type, and particularly with tricuspid valvuloplasty or replacement. Aortic regurgitation (a previously unreported problem) was also relatively common in this patient population. CONCLUSIONS: Patients with CCTGA are increasingly subject to CHF with advancing age; this complication is extremely common by the fourth and fifth decades. Tricuspid (systemic atrioventricular) valvular regurgitation is strongly associated with RV (anatomical right ventricle connected to aorta in CCTGA patients; systemic ventricle in CCTGA) dysfunction and CHF; whether it is causative or a secondary complication remains speculative.

Adult↗
PubMed2000

Improved assessment of mitral valve stenosis by volumetric real-time three-dimensional echocardiography.

OBJECTIVES: This study was performed to determine the feasibility, accuracy and reproducibility of real-time volumetric three-dimensional echocardiography (3-D echo) for the estimation of mitral valve area in patients with mitral valve stenosis. BACKGROUND: Planimetry of the mitral valve area (MVA) by two-dimensional echocardiography (2-D echo) requires a favorable parasternal acoustic window and depends on operator skill. Transthoracic volumetric 3-D echo allows reconstruction of multiple 2-D planes in any desired orientation and is not limited to parasternal acquisition, and could thus enhance the accuracy and feasibility of calculating MVA. METHODS: In 48 patients with mitral stenosis (40 women; mean age 61 +/- 13 years) MVA was determined by planimetry using volumetric 3-D echo and compared with measurements obtained by 2-D echo and Doppler pressure half-time (PHT). All measurements were performed by two independent observers. Volumetric data were acquired from an apical view. RESULTS: Although 2-D echo allowed planimetry of the mitral valve in 43 of 48 patients (89%), calculation of the MVA was possible in all patients when 3-D echo was used. Mitral valve area by 3-D echo correlated well with MVA by 2-D echo (r = 0.93, mean difference, 0.09 +/- 0.14 cm2) and by PHT (r = 0.87, mean difference, 0.16 +/- 0.19 cm2). Interobserver variability was significantly less for 3-D echo than for 2-D echo (SD 0.08cm2 versus SD 0.23cm2, p < 0.001). Furthermore, it was much easier and faster to define the image plane with the smallest orifice area when 3-D echo was used. CONCLUSIONS: Transthoracic real-time volumetric 3-D echo provides accurate and highly reproducible measurements of mitral valve area and can easily be performed from an apical approach.

Cardiac Volume↗
PubMed2000

Stereolithographic biomodeling to create tangible hard copies of cardiac structures from echocardiographic data: in vitro and in vivo validation.

OBJECTIVES: This study investigated the feasibility, accuracy and clinical potential of creating polymer hard copies of echocardiographic data using stereolithography. BACKGROUND: Three-dimensional (3D) echocardiography has so far been limited by the need to display reconstructed 3D objects on a two-dimensional screen. Thus, tangible stereolithographic polymer models created from echocardiographic data could enhance our spatial perception of cardiac anatomy and pathology. METHODS: Hard-copy replicas of water-filled latex balloon phantoms (n = 7) and porcine liver specimens (n = 12) were generated from echocardiographic images using stereolithography (computerized laser polymerization). In addition, we created 24 models of the mitral valve from 12 transesophageal studies (normal = 6, mitral stenosis n = 4, prolapse/flail leaflet n = 8, annular dilation n = 2, leaflet restriction n = 2 and following mitral valve repair n = 2). RESULTS: Excellent agreement was found for comparison of volumes (r = 0.98, SEE = 3.46 mm3, mean difference = 0.25 +/- 3.33 mm3) and maximal dimensions (r = 0.99, SEE = 0.16 cm, mean difference = 0.03 +/- 0.16 cm) between phantoms and their corresponding replicas. Visual and tactile examination of mitral valve models by two blinded observers allowed correct depiction of mitral valve anatomy and pathology in all cases. CONCLUSIONS: Stereolithographic modeling of echocardiographic images is feasible and provides tangible polyacrylic models that are true to scale, shape and volume. Such models offer accurate depiction of mitral valve anatomy and pathology in patients studied with transesophageal echocardiography. This technique could have substantial impact on diagnosis, management and preoperative planning in complex cardiovascular disorders.

Computer Systems↗
PubMed2000

Congenital malformations of the right atrium and the coronary sinus: an analysis based on 103 cases reported in the literature and two additional cases.

STUDY OBJECTIVES: Congenital malformations of the right atrium (RA) and the coronary sinus (CS) are rare, and only sporadic cases have been reported. Little is known about the clinical relevance of this disorder. We report on two patients, one with a giant RA diverticulum, the other with a diverticulum of the CS, and review 103 cases of such malformations that have been reported previously. DESIGN: A MEDLINE search was performed to collect all cases of congenital malformations of the RA and the CS reported in the literature between 1955 and 1998. Cases were classified into the following categories: (1) congenital enlargement of the RA; (2) single diverticulum of the RA; (3) multiple diverticula of the RA; and (4) diverticulum of the CS. Clinical presentation and outcome of the different types of malformations were analyzed. RESULTS: The patients most frequently presenting with symptoms were those with diverticula of the CS (n = 28) followed by those with single diverticula of the RA (n = 13), multiple diverticula (n = 4), and congenital enlargements of the RA (n = 60). The percentages of symptomatic patients were 93, 84, 75, and 53%, respectively. Symptoms were frequently caused by arrhythmias. Supraventricular tachycardia (SVT) was found in 42 of the patients (40%) and was most common in patients with diverticula of the CS (24 of 28 patients) and multiple atrial diverticula (3 of 4 patients). Sudden cardiac death was reported more frequently in patients with diverticula of the CS (18%) compared to those with congenital enlargement of the RA (5%) or single or multiple diverticula of the RA (6%). All seven patients with diverticula of the CS who were not treated with catheter or surgical ablation eventually died. CONCLUSION: Congenital malformations of the RA and the CS frequently are associated with arrhythmias. SVT and sudden cardiac death have been reported in a significant percentage of patients with diverticula of the CS.

Adult↗
PubMed1999

Mechanisms underlying aortic dilatation in congenital aortic valve malformation.

BACKGROUND: The high incidence of aortic disease in subjects with congenital aortic valve malformations suggests a causative relationship between these 2 conditions. The histological observation in aortic dilatation/aneurysm/dissection is Erdheim cystic medial necrosis (CMN), a noninflammatory loss of smooth muscle cells (SMCs), fragmentation of elastic fibers, and mucoid degeneration. METHODS AND RESULTS: To examine whether apoptosis is 1 of the mechanisms underlying CMN and aortic medial layer SMC loss, ascending aortic wall specimens from 32 patients were collected at cardiothoracic surgery and examined by histochemical staining and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling. From echocardiography results, 4 groups of patients were identified: bicuspid valve carriers with (bi/dil) or without (bi/0) aortic dilatation and tricuspid valve carriers with (tri/dil) or without (tri/0) aortic dilatation. Massive focal apoptosis was observed in the medial layers of bi/dil (mean apoptotic index [mAI], 8.1+/-6.0) and tri/dil (mAI, 8.1+/-8.3) compared with tri/0 (mAI, 0.9+/-1.2; P=0.0079 and P=0.037). In bi/0 (mAI, 9.1+/-5.7) compared with tri/0 (mAI, 0.9+/-1.2), rates of medial SMC apoptosis were increased (P=0.0025). Bi/dil (mean age, 40. 6+/-15.7 years) were significantly younger than tri/dil (mean age, 56.4+/-12.8 years) undergoing the same operation (P=0.0123). CONCLUSIONS: Premature medial layer SMC apoptosis could be part of a genetic program underlying aortic disease in patients with aortic valve malformations.

Adolescent↗