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W Voelker

Publications and source records attributed to W Voelker.

At least 19 recordsLinked to original sources
PubMed2005

[Quality assurance in echocardiography. Three-level system in formation and qualifying and concept of an external quality review].

Measures of quality assurance in echocardiography can be categorized according to standard principles into measures of reviewing structure, processing, and results. This document contains 1) the description of a three level system for education and qualifying in echocardiographic examinations (quality of structure) and 2) the draft of an external quality assurance process for reviewing the results of one echocardiographic investigator or of one laboratory of echocardiography (quality of results). The document also contains a draft description of a nationwide independent institution for certification, which is needed for both projects.A level 1 investigator should be able to perform and interpret a basic investigation. A basic investigation allows to exclude most of all cardiac diseases that can be diagnosed by echocardiography, and pathological findings should be filtered out. A level 2 investigator is able to perform an extended examination, and a comprehensive echocardiographic diagnosis can be established after her or his examination. Additional specific training and experience is necessary to be certified for TEE and stress echo examinations. A level 3 echocardiographer has done research work in echocardiography and should have performed certified teaching courses in echocardiography. The external quality assurance process should provide the possibility to certify the results and reports of a single investigator or of an echo laboratory, according to standard principles of reviewing the records. The process of certification is exclusively performed on a voluntary basis. The nationwide institution of certification should be part of the academy of education in cardiology of the German Society of Cardiology.

Cardiology↗
PubMed2004

[A structured report data set for documentation of echocardiographic studies--Update 2004].

A standardized documentation of echocardiographic studies is necessary to provide comparability of data and to realize software-based documentation and electronic communication, both essential for quality management in echocardiography.Therefore, the subgroup on "Standardization and LV function" of the working group on cardiovascular ultrasound of the German Cardiac Society developed a consensus report for documentation of echocardiographic studies, which was first published in 2000. This report represents the current update of the standardized documentation for echocardiography; its impact for quality management in conjunction with the "guidelines echocardiography" is discussed.

Data Collection↗
PubMed2003

[Documentation in the cardiac catheterization laboratory using electronic databases--experiences in 176 German cath labs].

Due to the introduction of a variety of new features to the German health system, such as a new reimbursement system for inpatient work based on diagnosis-related groups, an obligation to detailed documentation for total quality management, as well as due to the continuing increase in the amount of imaging and other data within invasive cardiology, the use of electronic databases for documentation in the cardiac cath lab is of significant importance. The user friendliness and robustness of the software system for daily clinical practice is crucial for the acceptance of electronic documentation systems by physicians, nurses and technicians. This survey was aimed to explore the current practice and experiences of German cardiac catheterization labs with electronic databases particularly designed for documentation in invasive cardiology, including report generation of cath studies, risk and complication management and logistics for medical material ordering for the cath lab. Of the 176 hospitals and practices having agreed in taking part in this surveillance 165, are currently using an electronic database for administration of medical data and study reports. In 64% of the cath labs, a sub-specialized software system for detailed documentation of the course and the results of an invasive procedure, the human and material resources used, generation of the cath report, and documentation of procedural and post-procedural complications for total quality management is used. The acceptance and satisfaction with the software solutions currently available reveals to be rather inhomogeneous. While user-friendliness and flexibility of a number of software products were positively mentioned, main issues, such as missing hardware of software interfaces with the hospital information system for patient administration, missing stability of several systems, image management too complex and report configuration too inconvenient for daily clinical practice, were criticized. In general, in the light of continuing increase of the amount of clinical and imaging data as well as due to the legal obligation of detailed procedural documentation in all areas of invasive cardiology, a documentation system based on electronic databases bears the potential of an enormous economization of the daily workload of a cardiac cath lab. Prerequisites for the acceptance of such a system in clinical practice is not only the stability and reliability of the system but also the ability to link such a sub-system to existing databases via suitable interfaces and the flexibility of the system for modification of its features to meet the individual requirements of each user.

Adult↗
PubMed2002

[Percutaneous revascularization of multivessel coronary disease using stents - a multicenter, prospective study].

BACKGROUND AND OBJECTIVE: Symptomatic patients with multivessel coronary disease (MVD) benefit from both coronary artery bypass grafting (CABG) and percutaneous coronary angioplasty (PTCA). The >>German Angioplasty Bypass Investigation<< (GABI-I) trial randomized patients to one of these treatment strategies between 1986 and 1991. In order to evaluate the impact of current technology, in particular coronary stents, the GABI-II trial was initiated, which in 1996 and 1997 prospectively enrolled patients according to the initial GABI-I criteria. PATIENTS AND METHODS: Into the study 136 consecutive patients (108 men, 28 women; 63 +/- 12 years) were included. Patients from GABI-I served as controls. RESULTS: A mean of 2.1 +/- 0.5 vessels were treated per patient (vs. 1.9 +/- 0.5 vessels in the PTCA arm of GABI-I) and 63 % of the lesions were covered with stents. With respect to the primary endpoint less patients remained with a CCS class III or IV in GABI-II after 12 months (1,5 % vs. 8 % in the PTCA arm of GABI-I, p<0,01). No patient required emergency or urgent bypass operation in GABI-II (vs. 9 % in GABI-I, p < 0.01). After 12 months, 8 % of the patients were sent for bypass surgery (CABG) vs. 21 % in GABI-I (p < 0.001), and 20 % (vs. 23 % in GABI-I) of the patients underwent Re-PTCA. The percentage of patients without reinterventions was 72 % vs. 56 % in GABI-I (p < 0.01), but remained lower compared to patients randomized to CABG in GABI-I (94 %, p < 0.001). CONCLUSION: PTCA in patients with MVD is still associated with a higher reintervention rate as compared with CABG. However, in contrast to angioplasty a decade ago, PTCA in conjunction with stents significantly lowered the need for subsequent revascularization, which was mainly driven by the reduced necessity for bypass surgery.

Aged↗
PubMed2002

[Cathi-training on virtual patients for catheter interventions].

In this paper we present a trainings system for catheter interventions, especially PCTAs also called ballon dilatation. Despite the large number of such interventions the education of the cardiologist is still based on learning on the patient. This means risk to the patient and additional cost. To overcome these problems we developed the CathI system (Catheter Instruction System), a realistic computerbased training system. It provides the physician with the same equipment found in a catheter laboratory, e.g. original control instruments for the flouroscopy system, syringes, catheters, and guide wires. CathI only replaces patient and C-arm by a virtual patient and a virtual x-ray system.

Angioplasty, Balloon, Coronary↗
PubMed2001

Use of intravascular ultrasound to compare effects of different strategies of lipid-lowering therapy on plaque volume and composition in patients with coronary artery disease.

BACKGROUND: We studied whether lipid-lowering therapy with atorvastatin (target LDL cholesterol [LDL-C] <100 mg/dL) compared with a moderate treatment regimen that used other lipid-lowering drugs led to a lesser progression of atherosclerosis and to different changes in plaque echogenicity in patients with coronary artery disease. METHODS AND RESULTS: This study was a 12-month, open-label, randomized, multicenter trial, which used serial 3D intracoronary ultrasound to calculate plaque volume and plaque echogenicity. After transcatheter therapy, 131 patients were randomized (atorvastatin n=65, usual care n=66). The target plaque had to be a minor lesion (ie, a diameter stenosis of <50% on angiography). After 12 months, mean LDL-C was reduced from 155 to 86 mg/dL in the atorvastatin group and from 166 to 140 mg/dL in the usual care group. Mean absolute plaque volume showed a larger increase in the usual care group compared with the atorvastatin group (usual care 9.6+/-28.1 mm(3), atorvastatin 1.2+/-30.4 mm(3); P=0.191). The hyperechogenicity index of the plaque increased to a larger extent for the atorvastatin group than for the usual care group, with a significant treatment effect for the percent change (atorvastatin 42.2%, usual care 10.1%; P=0.021). CONCLUSIONS: One year of lipid-lowering therapy to <100 mg/dL LDL-C most likely led to a slowdown of plaque growth of minor lesions. The significantly larger increase in plaque hyperechogenicity is most likely due to a change in plaque composition.

Anticholesteremic Agents↗
PubMed2001

Postpericardiotomy syndrome and cardiac tamponade as a late complication after pacemaker implantation.

In a 78-year old woman, pacemaker implantation was complicated by a transient perforation of the endocardial lead. The patient was in stable condition for up to 7 weeks after implantation, after which pericardial effusion and subacute cardiac tamponade developed and pericardiocentesis became necessary. This case illustrates that even after initially uneventful pacemaker lead perforation, careful, long-term follow-up is necessary to recognize the potential development of late postpericardiotomy syndrome.

Aged↗
PubMed2001

Haemodynamic quantification of different provocation manoeuvres by simultaneous measurement of right and left atrial pressure: implications for the echocardiographic detection of persistent foramen ovale.

AIMS: Persistent foramen ovale (PFO) is found in 9.2--32% of echocardiographic examinations. The gold standard for the detection of a PFO is transoesophageal echocardiography (TEE) and the mostly used provocation test is the Valsalva manoeuvre. The aim of our study was to evaluate the effectiveness of the Valsalva manoeuvre compared to other provocation tests by simultaneous haemodynamic measurements of the right and left atrial pressure. METHODS: Fifty patients underwent Swan-Ganz catheterization. Right atrial pressure and pulmonary capillary wedge pressure, which corresponds to the left atrial pressure, were measured simultaneously. The following manoeuvres were compared: the Valsalva manoeuvre, coughing, deep inspiration and expiration pressures of 20 mmHg, 40 mmHg and 60 mmHg. The main objective of our study was to compare the occurrence of pressure gradients (right atrial pressure> left atrial pressure). For further quantification mean gradients, time duration of pressure overlap, as well as products of mean gradients and overlap time were analysed. RESULTS: During the Valsalva manoeuvre a significant pressure gradient could be observed in 84% of the patients, followed by an expiration pressure of 60 mmHg (82%), inspiration (78%), expiration pressure of 40 mmHg (76%), coughing (75%) and an expiration pressure of 20 mmHg (62%). Comparing the mean gradients and the products of mean gradients and overlap time duration during the different manoeuvres, we could detect the significantly best results with the Valsalva manoeuvre. CONCLUSIONS: The Valsalva manoeuvre might be the most effective test to provoke a right-to-left atrial shunt for the detection of a PFO during echocardiographic examinations.

Adult↗
PubMed2001

A novel perfusion catheter for hybrid procedures in minimally invasive bypass surgery.

BACKGROUND: Combined off-pump bypass grafting and percutaneous coronary intervention (hybrid procedures) is supposed to be beneficial for high-risk patients. We developed a novel perfusion catheter to facilitate these hybrid interventions. METHODS: First, we tested coagulatory activation in vitro. Afterwards, 6 landrace pigs underwent active coronary perfusion of the LAD. In a second study, 15 pigs underwent off-pump bypass surgery (LIMA to LAD grafting) and the catheter was used to provide myocardial perfusion and prevent bleeding at the site of the coronary anastomosis. RESULTS: In the in vitro perfusion studies, no activation of coagulation or clotting occurred. Active coronary perfusion was feasible without signs of regional myocardial ischemia or coagulation over a 50-minute period. During off-pump bypass surgery, the catheter prevented bleeding in the operation field and facilitated the surgical procedure. CONCLUSION: The new perfusion catheter can optimize the conditions of off-pump bypass surgery by preventing bleeding in the operation field, maintaining myocardial perfusion and allowing direct angiographic control of the anastomosis. Therefore, this new technique could be an important tool to facilitate hybrid interventions.

Anastomosis, Surgical↗
PubMed2001

Persistence of the eustachian valve in secundum atrial septal defects: possible implications for cerebral embolism and transcatheter closure procedures.

Transcatheter closure of large secundum atrial septal defects is now accepted clinical practice. With the introduction of easily applicable closure devices the indications for this procedure have been expanded to include the closure of patent foramen ovale after cerebral stroke of unknown origin. In some of these patients a persistent eustachian valve is present. The clinical relevance of this finding is still unclear. A 36 year old patient with a brainstem stroke of unknown origin and a secundum atrial septal defect in combination with a persisting prominent eustachian valve is reported. The potential role of the eustachian valve in the genesis of the stroke and the difficulties during transcatheter closure of the defect because of the persisting valve are discussed.

Adult↗
PubMed2001

Assessment of myocardial infarction in humans with (23)Na MR imaging: comparison with cine MR imaging and delayed contrast enhancement.

PURPOSE: To demonstrate the feasibility of sodium 23 ((23)Na) magnetic resonance (MR) imaging for assessment of subacute and chronic myocardial infarction and compare with cine, late enhancement, and T2-weighted imaging. MATERIALS AND METHODS: Thirty patients underwent MR imaging 8 days +/- 4 (subacute, n = 15) or more than 6 months (chronic, n = 15) after myocardial infarction by using a (23)Na surface coil with a double angulated electrocardiogram-triggered three-dimensional gradient-echo sequence at 1.5 T. In addition, cine, inversion-recovery gradient-echo, and, in the subacute group, T2-weighted images (n = 9) were obtained. Myocardial infarction mass was depicted as elevated signal intensity or wall motion abnormalities and expressed as a percentage of total left ventricular mass for all modalities. Correlations were tested with correlation coefficients. RESULTS: All patients after subacute infarction and 12 of 15 patients with chronic infarction had an area of elevated (23)Na signal intensity that significantly correlated with wall motion abnormalities (subacute; r = 0.96, P <.001, and chronic; r = 0.9, P <.001); three patients had no wall motion abnormalities or elevated (23)Na signal intensity. Only 10 patients in the subacute and nine in the chronic group revealed late enhancement; significant correlation with (23)Na MR imaging occurred only in subacute group (r = 0.68, P <.05). Myocardial edema in subacute infarction correlated (r = 0.71, P <.05) with areas of elevated (23)Na signal intensity but was extensively larger. CONCLUSION: (23)Na MR imaging demonstrates dysfunctional myocardium caused by subacute and chronic myocardial infarction.

Adult↗
PubMed2000

[A standardized documentation structure for data documentation in echocardiography. Work Team on Standards and LV Function of the Work Group on Cardiovascular Ultrasound of the German Society of Cardiology, Heart and Circulation Research].

Presently, there are no well-defined standards for documentation of echocardiographic studies. Nevertheless, standards are essential to provide comparability of data and to realize electronic communication, both essential for quality management in echocardiography. Therefore, the working group "Standards and LV function" of the German Society of Cardiology developed a consensus for documentation of echocardiographic studies. In the present paper this consensus is presented and illustrated by typical clinical examples. Additionally, a prototype of a user-oriented software based on this data set is presented. The complete data set for transesophageal and transthoracic echocardiography and the software prototype can be downloaded at http:@echo.ma.uni-heidelberg.de.

Aortic Valve Stenosis↗
PubMed2000

[Noise field findings in 24 patients with coronary heart disease].

PURPOSE: In earlier studies it was shown that patients with vascular disturbances (e.g. sudden hearing loss) had white-noise field campimetry abnormalities despite normal visual fields. The aim of this study was to clarify whether patients with coronary heart disease (CHD) have such disturbances in the white-noise field campimetry, too. PATIENTS AND METHODS: Twenty-four patients (m:f = 23:1; mean age 58 +/- 9 years) with an angiographically documented CHD and 30 healthy controls (m:f = 29:1; mean age 54 +/- 7 years) were examined. In order to evaluate the morphological and functional ocular status, we examined the following parameters: morphological status, visual acuity, intraocular pressure, perimetry (Tübinger Automatic Perimeter 2000 ct, Oculus) and white-noise field campimetry (Tübinger Electronic Campimeter, Oculus). RESULTS: Fifteen patients had had a cardiac infarction. Twenty-one patients, but only 6 controls had alterations in perilimbal vessels of the conjunctiva and sixteen patients had a tortuousity of retinal vessels. The visual acuity, the intraocular pressure, the cup/disc ratio and the visual fields were within normal ranges. However, twenty patients and 5 controls were abnormal in the white-noise field campimetry. DISCUSSION: Although patients with CHD appeared unaffected in the standard eye examinations, the disturbances in the white-noise field campimetry indicated a functional visual impairment. Together with the changes in the perilimbal vessels of the conjunctiva and the retinal vessels, a disturbed ocular microcirculation as the underlaying cause could be discussed.

Adult↗
PubMed1999

Evaluation of systolic performance by automated impedance cardiography.

Impedance cardiography (ICG) is a noninvasive method for evaluating cardiac function. Left ventricular stroke volume (SV) is the basic hemodynamic parameter derived from thoracic bioimpedance curves. Issues of our study were to investigate the diagnostic value of other indices of left ventricular systolic performance, such as ejection fraction (EF), index of contractility (IC), peak flow index (PFI), and acceleration index (ACI), which can also be calculated by ICG. Forty patients (PTS) with suspected coronary artery disease (CAD) were monitored by automated ICG during pharmacologic stress testing with dobutamine. All PTS underwent subsequent cardiac catheterization. In PTS with single vessel disease, the dobutamine-induced changes of SV, EF, IC, PFI, and ACI were comparable to those of PTS without CAD. In PTS with multivessel disease, the impaired systolic performance during dobutamine stimulation could be clearly demonstrated. We conclude that automated ICG is a useful method for monitoring SV and other indices of left ventricular systolic performance for detecting PTS with ischemic left ventricular dysfunction during cardiovascular stress.

Aged↗
PubMed1999

Occurrence of a saccular pseudoaneurysm formation two weeks after perforation of the left anterior descending coronary artery during balloon angioplasty in acute myocardial infarction.

We describe the occurrence of a localized saccular pseudoaneurysm in a 69-year-old patient 2 weeks after perforation of the left anterior descending coronary artery during balloon angioplasty in acute myocardial infarction. The therapy of perforations requires prolonged balloon inflations, perfusion balloons, covered stents, or surgery. Coronary peudoaneurysm formations are rare; their therapy requires covered stents or surgery. Cathet. Cardiovasc. Intervent. 47:341-346, 1999.

Aged↗
PubMed1999

[Risk of invasive diagnosis with retrograde catheterization of the left ventricle in patients with acquired aortic valve stenosis].

In patients with aortic valve stenosis, the determination of the transstenotic pressure gradient is usually performed by cardiac catheterization with retrograde passage of the aortic valve. The aim of this study was to determine retrospectively the risk of the invasive examination with retrograde catheterization of the left ventricle and predictors for an increased risk. From 1984 to 1995, 457 patients (63 +/- 11 years) with aortic stenosis were investigated in the Medizinische Klinik Tübingen. In 435 patients (95.2%), the retrograde catheterization of the left ventricle was successful; in 19 cases a transseptal left heart catheterization was performed, and in 3 patients an invasive determination of the pressure gradient was not assessed. Complications occurred in 39 patients (8.5%). 5 patients died due to the catherization procedure (mortality rate 1.1%), 2 of them as a consequence of perforation of the left ventricle, one patient of heart failure, one of myocardial infarction, and another of fulminant pulmonary embolism. Four procedures (0.9%) were complicated by cerebral embolism, in 3 patients a pericard tamponade occurred, and in one case caused by transseptal punction of the interatrial septum. The most complications were peripheral vascular problems in 19 patients (4.2%). Predictors for increased risk dur to retrograde catheterization were age > 70 years (p = 0.008) and aortic valve area < or = 0.7 cm2 (p = 0.02). patients with a doppler echocardiographic instantaneous pressure gradient > or = 70 mm Hg were more likely to sustain a complication (p = 0.04). The retrograde catheterization of a stenotic aortic valve was successful in most cases. In approximately 2% of patients, complications occurred which can be attributed directly to retrograde catheterization and with significant higher frequency in patients over 70 years and with severe stenosis. Especially in these cases, invasive determination of the gradient should not be performed if reliable doppler echocardiographic information is available.

Adult↗
PubMed1999

Extent, determinants and clinical importance of pressure recovery in patients with aortic valve stenosis.

AIMS: In experimental studies the recovery of pressure distal to stenotic valve orifices has been well described. We evaluated the extent, determinants, and clinical importance of pressure recovery in patients with aortic valve stenosis. METHODS AND RESULTS: The study was performed in 37 patients with aortic valve stenosis, in whom cardiac catheterization was performed and left ventricular and aortic pressures were determined using a high-fidelity multi-tip micromanometer catheter. To register the pressure waveforms accurately the catheter was positioned so that the proximal micromanometer was in the left ventricle, the second at the site of minimal pressure in the vena contracta, and the third (the most distal) in the ascending aorta 16 cm further downstream. The amount of pressure recovery within the ascending aorta was up to 44% of the maximal pressure drop. The index pressure recovery was directly correlated to the Gorlin-derived aortic valve area (r=0.80) and indirectly correlated to the ratio of aortic valve area and the cross-sectional area of the ascending aorta. CONCLUSIONS: This clinical study confirmed experimental data, that index pressure recovery is dependent on the ratio of the effective valve area and the cross-sectional area of the ascending aorta. Pressure recovery may need to be considered in patients with mild to moderate aortic stenosis and with a small cross-sectional area of the ascending aorta.

Adult↗