Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    facet.materialart.
    facet.materialart.
    German Medical Science; Düsseldorf, Köln
    In:  33rd International Congress on Electrocardiology; 20060628-20060701; Cologne; DOC06ice021 /20070208/
    Publication Date: 2007-02-09
    Keywords: ddc: 610
    Language: English
    Type: conferenceObject
    Signatur Availability
    BibTip Others were also interested in ...
  • 2
    facet.materialart.
    facet.materialart.
    German Medical Science; Düsseldorf, Köln
    In:  33rd International Congress on Electrocardiology; 20060628-20060701; Cologne; DOC06ice024 /20070208/
    Publication Date: 2007-02-09
    Keywords: ddc: 610
    Language: English
    Type: conferenceObject
    Signatur Availability
    BibTip Others were also interested in ...
  • 3
  • 4
    Keywords: DOPPLER ; Germany ; IN-VIVO ; MODEL ; MODELS ; CT ; VOLUME ; NEW-YORK ; ACCURACY ; computed tomography ; HEART ; INTEROBSERVER VARIABILITY ; PIGS ; RESOLUTION ; SURGERY ; validation
    Abstract: Background. Cardiac functional assessment represents the basis for diagnostics and cardiac operation planning. Spiral computed tomography (CT) combines the advantages of three-dimensional imaging and high temporal resolution when using gating techniques. However, in vivo validation data of this novel imaging technology are lacking. The purpose of this study was to validate in vivo the new imaging method using retrospective gating and to evaluate the clinical usefulness of the achieved temporal resolution. Methods. In domestic pigs (n = 10, weight 35 to 40 kg) a flowmeter was placed surgically on the ascending aorta. Flow velocity integrated over systole served as the gold standard for left ventricular (LV) stroke volume (LVSV-FM). CT signal, projection data, pacemaker signal, and flow velocity were recorded simultaneously at constant heart rate (pacemaker, 90 beats per minute). End-systolic and end-diastolic frames were calculated by retrospective gating. LV volumes were traced, the difference representing CT stroke volume (LVSV-CT). Image data were three-dimensionally reconstructed using ray- tracing. Results. Temporal resolution was 170 ms. Correlation of stroke volumes was high (r = 0.94, mean difference 1.75 mL). Intraobserver (0.49 mL, for LVEDV, 0.31 for LVESV) and interobserver variability (p = 0.21 and p = 0.06, respectively) were low. Postprocessing resulted in four-dimensional beating- heart models useful for operation planning. Conclusions. Spiral CT using retrospective gating was validated in vivo. Clinically acceptable temporal resolution and accuracy in determining cardiac stroke volumes were found. As a true volumetric imaging modality the method may now play an important role in computer- assisted diagnostics and surgery. (C) 2003 by The Society of Thoracic Surgeons
    Type of Publication: Journal article published
    PubMed ID: 12645712
    Signatur Availability
    BibTip Others were also interested in ...
  • 5
    Keywords: Germany ; HEART ; PATIENT ; FLOW ; RECONSTRUCTION ; COLOR DOPPLER ; VELOCITY ; RE ; SOFTWARE ; STENOSIS ; analysis ; PROFILES ; 3D ; TRANSESOPHAGEAL ECHOCARDIOGRAPHY ; technique
    Abstract: The aim of this study was to analyse flow characteristics of two different prosthetic valves by means of a non-invasive 3D Doppler technique. As previously demonstrated, negative velocity peaks within a 3D-Doppler profile significantly correlate with the severity of aortic stenosis. Transesophageal echocardiography was performed in 42 patients with normal aortic valves and in 35 patients after aortic valve replacement (bileaflet n=23, tilting-disc n=12). Three-dimensional reconstruction of color Doppler data was performed by the EchoAnalyzer software developed at our institution. Cross-section velocity distribution in the ascending aorta was analysed 2 cm distal to the aortic valve in 3 different sectors (non-coronary (NC), left-coronary (LC) or right-coronary (RC)). The percentages of negative velocity values (PNVV) in native aortic valves (6.8+/-6.4%, range: 0-21.8%) were significantly lower (P〈0.0001) than in prosthetic valves (bileaflet: 38.5+/-18.5%, range: 13.2-71%; tilting-disc: 47.2+/-17.6%, range: 21.7-78.1%). Significant differences between normal and prosthetic valves were found in all different sectors. Furthermore, Medtronic Hall showed significantly higher PNVV than St. Jude Medical within the LC sector (P=0.03). This method, which allows non-invasive analysis of 3D flow distributions in patients, revealed significant differences between prosthetic valves and native valves as well as among different prosthetic types.
    Type of Publication: Journal article published
    PubMed ID: 17670437
    Signatur Availability
    BibTip Others were also interested in ...
  • 6
    Keywords: Germany ; CLASSIFICATION ; VOLUME ; DISEASE ; PATIENT ; COMPLEX ; COMPLEXES ; DYNAMICS ; MR ; LESIONS ; REPAIR ; REGIONS ; QUANTITATIVE ASSESSMENT ; SURGICAL-TREATMENT ; cardiac surgery ; function ; CARDIOMYOPATHY ; 3-DIMENSIONAL COLOR DOPPLER ; annuloptasty ; coronary artery disease ; ischemic mitral regurgitation ; OVINE MODEL ; REPLACEMENT ; transesophageal 3D-echocardiography ; VALVE RECONSTRUCTION
    Abstract: Objective: Recent studies in animals showed that regional annulus distortion is a major determinant of ischemic mitral regurgitation (IMR) and accordingly suggested new surgical approaches with asymmetrical annuloplasty rings. As accurate measurement of annulus in patients is still a challenge, we performed this study to analyze the changes in three-dimensional annular geometry in patients with IMR compared to primary valvular lesions. Methods: We studied 110 patients divided into three groups: (1) 30 with coronary artery disease without IMR, (2) 38 with chronic IMR, and (3) 42 with MR due to primary valvular lesions. Longitudinal and septal-lateral annulus diameters; global diastolic and systolic annular area and its percentual shortening, diastolic and systolic areas of six regions corresponding to the segmental Carpentier classification were measured by 3D-echocardiography. The degree of MR was assessed by three-dimensional color Doppler. Global and regional left ventricular geometry were assessed by sphericity index and by measuring anterior and posterior tethering of papillary muscles. Results: Patients with significant IMR (group 2) showed larger longitudinal (52.7 +/- 3.9 mm vs 41.8 +/- 2.9 mm; p 〈 0.01) and antero-lateral (31.8 +/- 3.5 mm vs 26.7 +/- 2.8 mm; p 〈 0.01) annular diameters than the patients with MR due to primary valvular lesions (group 3). Diastolic (997.8 +/- 64.9 mm(2) vs 700.7 +/- 46.8 mm(2); p 〈 0.01) and systolic (894.9 +/- 57.3 mm(2) vs 547.3 +/- 35.0 mm(2); p 〈 0.01) annular areas were larger in group 2 than in group 3. Annular area change was significantly lower in the group with ischemic mitral. regurgitation than in the group with primary valvular lesions (10.3 +/- 1.1% vs 21.9 +/- 1.6%; p 〈 0.01). Regional annular areas of the six sectors were homogeneously larger in group 2 than in group 3. The sector P3 did not show larger area than the other ones. The degree of MR, as assessed by the volumes of regurgitant jets, was higher in the group with primary valvular lesions than in the patients with IMR (32.6 +/- 13.4 cm(3) vs 23.1 +/- 11.1 cm(3); p 〈 0.01). Conclusions: This study showed that annular enlargement in patients with IMR affects the different annular regions to the same extent. An ideal surgical repair of IMR should be individually tailored after quantitative assessment measurement of geometry and function of each single component of the mitral. valve complex. (c) 2005 Elsevier B.V. All. rights reserved
    Type of Publication: Journal article published
    PubMed ID: 16439153
    Signatur Availability
    BibTip Others were also interested in ...
  • 7
    Keywords: Germany ; VOLUME ; PATIENT ; LESIONS ; REPAIR ; COLOR DOPPLER ; cardiac surgery ; CARDIOMYOPATHY ; coronary artery disease ; ischemic mitral regurgitation ; OVINE MODEL ; REPLACEMENT ; VALVE RECONSTRUCTION ; annuloplasty ; GEOMETRY ; ischernic mitral regurgitation ; left ventricular geometry ; three-dimensional echocardiography
    Abstract: Background: The aim of this study was to investigate the relationship between LV geometry, annular shape and the amount of regurgitation in patients with ischernic mitral regurgitation (group 1, n = 30) compared to patients with primary mitral valve lesions (group 2, n = 30). Methods: LV geometry was assessed by the sphericity index, i.e., LV volume divided by the volume of a sphere with a diameter equal to the longest axis. Annular geometry was evaluated by diameters, areas and their percentual shortening. The degree of mitral regurgitation was assessed as jet volumes by 3D-echocardiography. Results: Group I showed significantly larger longitudinal (54.3 +/- 3.1 vs. 40.9 +/- 2.6 mm) and antero-posterior (32.2 +/- 3.3 vs. 27.1 +/- 2.9 mm) annulus diameters and areas (993.3 +/- 66.6 vs. 702.1 +/- 47.9 mm(2)) than group 2. No asymmetric annular enlargement was found in either group. Annular enlargement correlated to the degree of mitral regurgitation in group I but not in group 2. Annular area shortening was significantly impaired in group 2 and the sphericity index was larger in group 1 than in group 2. In group 1, the sphericity index was significantly correlated to the degree of mitral regurgitation (r = 0.87; p 〈 0.001). Conclusions: These findings suggest that ischemic mitral regurgitation was mostly associated with a global left ventricular enlargement, in which annulus dilatation and its reduced contraction play a significant role
    Type of Publication: Journal article published
    PubMed ID: 17089311
    Signatur Availability
    BibTip Others were also interested in ...
  • 8
    Keywords: ADULT, ADULTS, AGE, ASSOCIATION, cardiovascular, CHILDREN, CLASS-I, COMBINATION, COMPLICATIONS, DISE
    Abstract: Background. We asked whether aortic valve replacement using a mechanical prosthesis would allow normalization of left ventricular function and structure in children and young adults. Methods. We performed a clinical follow-up examination in 30 patients with aortic valve replacement at 25 years of age or younger, including conventional and tissue Doppler echocardiography and magnetic resonance imaging. Results. Aortic valve replacement was performed at the median age of 14.3 years (range, 7.6 to 24.3 years) using a mechanical prosthesis (St. Jude Medical; median diameter, 23 mm; range, 17 to 27 mm). Indications were severe aortic stenosis in 6 of 30 patients, aortic regurgitation in 20 of 30 patients, or a combination of aortic stenosis and regurgitation (4 of 30 patients). Aortic valve replacement was a reoperation in 12 of 30 patients who primarily underwent aortic valvotomy at a median of 7.1 years (range, 1.0 to 11.3 years). In-hospital mortality was 0%. Follow-up was a median of 6 years (range, 1.2 to 14.5 years). Twenty-nine of 30 patients were in New York Heart Association functional class I without thromboembolic complications, cerebrovascular accidents, or major bleeding on oral anticoagulation. Left ventricular dilatation before aortic valve replacement was present in 20 of 30 patients but normalized in all but 4 patients on follow-up. Most patients showed a normal end-diastolic volume on magnetic resonance imaging, and 23 of 26 patients showed a normal left ventricular ejection fraction (median, 0.53; range, 0.33 to 0.75). Peak systolic strain of the left ventricular myocardium was a median of -13.3% (range, -0.5% to -31%), and was normal in 28 of 30 patients. Conclusions. Aortic valve replacement in children and young adults offers a good treatment option and may lead to normalization of left ventricular size and function in most patients
    Type of Publication: Journal article published
    PubMed ID: 18222274
    Signatur Availability
    BibTip Others were also interested in ...
  • 9
    Keywords: BLOOD ; Germany ; FOLLOW-UP ; imaging ; QUANTIFICATION ; screening ; TOOL ; PATIENT ; BLOOD-FLOW ; CONTRAST ; INTERVENTION ; blood flow ; FLOW ; MR ; MRI ; MAGNETIC-RESONANCE ; PATTERNS ; AGE ; REPAIR ; sensitivity ; specificity ; MR-ANGIOGRAPHY ; CT ANGIOGRAPHY ; ANGIOGRAPHY ; MR angiography ; FEASIBILITY ; MR imaging ; ultrasound ; THORACIC AORTA ; ENHANCED MR-ANGIOGRAPHY ; STENOSIS ; PROFILES ; CRITERIA ; correlation ; CATHETER ; aortic coarctation ; Bernoulli ; COLLATERAL FLOW ; DISCREPANCIES ; flow profiles ; pediatric ; phase-contrast MRI ; pressure gradient ; PRESSURE-GRADIENTS
    Abstract: Background: Previous studies have suggested the feasibility of a non-invasive quantification of vascular trans-stenotic pressure gradients (AP) by phase-contrast MR imaging (PC-MRI). Our purpose was to assess the value of MRI estimated pressure gradients as a screening tool for assessing hemodynamically significant (re-)coarctation of the aorta (CoA) in pediatric patients. Methods: Forty-three patients (median age (range), 16 (5-25) years) with CoA (38 postoperative and 5 native) and clinically suspected hemodynamically significant stenosis underwent quantitative and semi-quantitative PC-MRI blood flow measurements and 3D MR-angiography, Doppler ultrasound (US) and conventional catheter angiography (CCA, n =20). Estimated Delta P for each modality was correlated with percent stenosis. Results: The percent stenosis correlated only moderately with Delta P-MRI (r=0.55, p 〈 0.001) and Delta P-CCA (r=0.48, p 〈 0.001). Only moderate correlations were observed between Delta P-MRI vs. Delta P-CCA (r=0.54, p=0.02) and vs. Delta P-US (r=0.40, p=0.01). In contrast, semi-quantitative analysis of PC-MRI flow profiles predicted with good sensitivity (88%) and specificity (88%) who would be operated on. Thirteen patients met hemodynamic and percent stenosis criteria by CCA for surgical intervention. Conclusion: Measured pressure gradients using PC-MRI should be used cautiously when assessing patients for recoarctation of the aorta. The analysis of blood flow profiles by PC-MRI might be a promising alternative in assessing the hemodynamic significance of CoA. (c) 2005 Elsevier Ireland Ltd. All rights reserved
    Type of Publication: Journal article published
    PubMed ID: 16377005
    Signatur Availability
    BibTip Others were also interested in ...
  • 10
    Keywords: Germany ; GENERATION ; SYSTEM ; TOOL ; VOLUME ; DISEASE ; SURGERY ; PATIENT ; PARAMETERS ; Jun ; MANAGEMENT ; monitoring ; cardiac surgery ; ejection fraction ; pulmonary artery catheter ; right ventricle ; thermodilution ; transesophageal 3D echocardiography ; TRANSESOPHAGEAL ECHOCARDIOGRAPHY
    Abstract: Objective: Right ventricular function is an important aspect of global cardiac performance which affects patients' outcome after cardiac surgery. Due to its geometrical complexity, the assessment of right ventricular function is still a very difficult task. Aim of this study was to investigate the value of a new technique for intraoperative assessment of right ventricle based on transesophageal 3D-echocardiography, and to compare it to volumetric thermodilution by using a new generation of fast response thermistor pulmonary artery catheters. Methods: Twenty-five patients with coronary artery disease underwent 68 intraoperative measurements by 3D-echocardiography and thermodilution simultaneously. Following parameters were analysed: right ventricular end-diastolic volume (RVEDV), end-systolic volume (RVESV) and ejection fraction (RVEF). Pulmonary, systemic and central venous pressures were simultaneously recorded. Segmentation of right ventricular volumes were obtained by the 'Coons-Patches' technique, which was implemented into the EchoAnalyzer (R), a multitask system developed at our institution for three-dimensional functional and structural measurements. Results: Right ventricular volumes obtained by 3D-echocardiography did not show significant correlations to those obtained by thermodilution. Volumetric thermodilution systematically overestimates right ventricular volumes. Significant correlations were found between RVEF measured by 3D-echocardiography and those obtained by thermodilution (r=0.93; y=0.2+0.80x; SEE=0.03; P 〈 0.01). Bland-Altmann analysis showed that thermodilution systematically underestimates RVEF. The bias for measuring RVEF was +15.6% with a precision of +/- 4.3%. The patients were divided into two groups according to left ventricular function. The group of patients with impaired function showed significantly tower right ventricular ejection fraction (44.1 +/- 4.6 vs. 55.1 +/- 3.9%; P 〈 0.01). Conclusions: Three-dimensional echocardiography provides a useful non-invasive tool for intraoperative and serial assessment of right ventricular function. This new technique, which overcomes the limitations of previous methods, may offer key insights into management and outcome of patients with severe impairment of cardiac function. (c) 2005 Elsevier B.V. All rights reserved
    Type of Publication: Journal article published
    PubMed ID: 15896606
    Signatur Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...