Wolfgang Hatzmann
Ruhr University Bochum
Network
Latest external collaboration on country level. Dive into details by clicking on the dots.
Publication
Featured researches published by Wolfgang Hatzmann.
British Journal of Obstetrics and Gynaecology | 2008
S. Schiermeier; S. Pildner Von Steinburg; A. Thieme; J. Reinhard; Martin Daumer; Michael Scholz; Wolfgang Hatzmann; K. T. M. Schneider
Objective To identify sensitivity and specificity of computerised cardiotocography (CTG) analysis for fetal acidosis during delivery.
PeerJ | 2013
Stephanie Pildner von Steinburg; Anne-Laure Boulesteix; Christian Lederer; Stefani Grunow; S. Schiermeier; Wolfgang Hatzmann; Karl-Theodor M. Schneider; Martin Daumer
Aim. There is no consensus about the normal fetal heart rate. Current international guidelines recommend for the normal fetal heart rate (FHR) baseline different ranges of 110 to 150 beats per minute (bpm) or 110 to 160 bpm. We started with a precise definition of “normality” and performed a retrospective computerized analysis of electronically recorded FHR tracings. Methods. We analyzed all recorded cardiotocography tracings of singleton pregnancies in three German medical centers from 2000 to 2007 and identified 78,852 tracings of sufficient quality. For each tracing, the baseline FHR was extracted by eliminating accelerations/decelerations and averaging based on the “delayed moving windows” algorithm. After analyzing 40% of the dataset as “training set” from one hospital generating a hypothetical normal baseline range, evaluation of external validity on the other 60% of the data was performed using data from later years in the same hospital and externally using data from the two other hospitals. Results. Based on the training data set, the “best” FHR range was 115 or 120 to 160 bpm. Validation in all three data sets identified 120 to 160 bpm as the correct symmetric “normal range”. FHR decreases slightly during gestation. Conclusions. Normal ranges for FHR are 120 to 160 bpm. Many international guidelines define ranges of 110 to 160 bpm which seem to be safe in daily practice. However, further studies should confirm that such asymmetric alarm limits are safe, with a particular focus on the lower bound, and should give insights about how to show and further improve the usefulness of the widely used practice of CTG monitoring.
Pediatric Research | 2006
Peter Van Leeuwen; S. Schiermeier; Silke Lange; A. Klein; D. Geue; Wolfgang Hatzmann; Dietrich Grönemeyer
Prenatal growth deficiencies as well as gender have been associated with cardiovascular disease in later life. It is also known that the duration of fetal cardiac time intervals (CTI) are dependent on fetal development. The aim of this work was to examine the relationship between fetal CTI in healthy and intrauterine growth retardation (IUGR) fetuses, taking gender into account. A total of 269 magnetocardiograms (MCG) were obtained in 47 healthy and 27 IUGR pregnancies. In each signal-averaged MCG, durations of CTI were determined. Age- and heart rate–corrected values were compared between normal and IUGR fetuses separately with respect to gender. Overall, there was an association between atrial and ventricular conduction times and estimated fetal body weight. In female fetuses, IUGR was associated with shorter P WAVE, PQ segment, PR interval, and QRS complex and longer STT and QT intervals. For males, this was so only for P wave, QRS complex, and STT interval. The shortening of conduction times in IUGR may be explained by reduced cardiac muscle mass associated with lower body weight. On the other hand, the gender-specific differences, particularly in the IUGR fetuses may be due to hormonal factors.
Physiological Measurement | 2014
Peter Van Leeuwen; Lisa Werner; Ziad Hilal; S. Schiermeier; Wolfgang Hatzmann; Dietrich Grönemeyer
This study examines signal availability in fetal electrocardiogram (FECG) beat-to-beat acquisition and the accuracy of fetal heart rate variability (HRV) analysis in the clinical setting using a commercially available FECG monitor. Signal availability was examined in 130 FECG recordings of 0.3-17.5 h duration collected in 63 fetuses (25th-42nd week of gestation) under uncontrolled conditions. Identification of R-peaks demonstrated a signal loss of 30% ± 24% with 3.6 ± 1.7 signal gaps per minute. Median duration of the gaps within a recording was 1.8 ± 0.2 s. Per hour of recording, 1.8 ± 2.1 episodes of 5 min of uninterrupted data were found. Signal availability improved with gestational age and was poorer in women with high body-mass index. Fetal HRV between weeks 36-42 was examined on the basis of 5 min RR-interval episodes obtained under controlled quiet conditions in 55 FECG compared to 46 high quality fetal magnetocardiograms. There were no differences in RR-interval duration, its standard deviation and low frequency power. However, various measures of short-term HRV were significantly higher in the FECG data: root mean square of successive differences (10.0 ± 1.8 versus 6.6 ± 3.0 ms, p < 0.001, high frequency spectral power (24 ± 12 versus 13 ± 13 ms(2), p < 0.001) and approximate entropy (0.86 ± 0.16 versus 0.73 ± 0.24, p = 0.007). We conclude that, in spite of considerable signal loss, FECG recordings can accurately estimate heart rate and its overall variance. However, measures that quantify short-term beat-to-beat HRV will be compromised due to possible recurring inappropriate detection of single R-peaks.
Urologia Internationalis | 2010
Carolin Banerjee; Wolfgang Hatzmann; S. Schiermeier; Katrin Sachse; Martin Hellmich; Günter Karl Noé
Introduction: No validated questionnaire that evaluates vaginal symptoms is currently available in the German language. Here, we report the translation and validation process of the German ICIQ-VS. Subjects: Pilot study: 10 patients without any specific disease. Main study: 58 patients (cases) suffering from genital descensus higher than grade 1 pelvic organ prolapse quantification (POPQ) and 51 patients (controls) without vaginal affections. Methods: To establish a cultural-adaptive equivalent in German, recommendations from Guillemin et al. [J Clin Epidemiol 1993;46:1417–1432] were carefully followed. Participants of the main study were asked to fill in the questionnaire at three time points [baseline (T1), 7 days later (T2) and 1 year later (T3)]. Reliability, validity and sensitivity to change were evaluated. Results: In our pilot study, all questionnaire items were correctly interpreted and answered. In the main study, no changes from the original format were observed after translation and cultural adaptation. For the cases, internal consistency was acceptable (Cronbach’s alpha 0.72–0.79) and test-retest reliability was moderate to near-perfect for single items (weighted kappa 0.67–0.94). Sensitivity to change and content validity were excellent. Construct validity revealed statistically significant differences between groups. Conclusion: The ICIQ-VS has successfully been translated and validated into the German language.
Physiological Measurement | 2015
Dirk Hoyer; Uwe Schneider; Eva-Maria Kowalski; Alexander Schmidt; Otto W. Witte; Ekkehard Schleußner; Wolfgang Hatzmann; Dietrich Grönemeyer; Peter Van Leeuwen
With the objective of evaluating the functional maturation age and developmental disturbances we have previously introduced the fetal autonomic brain age score (fABAS) using 30 min fetal magnetocardiographic recordings (fMCG, Jena). The score is based on heart rate pattern indices that are related to universal principles of developmental biology. The present work aims at the validation of the fABAS methodology on 5 min recordings from an independent database (fMCG, Bochum).We found high agreement of fABAS obtained from Jena normal fetuses (5 min subsets, n = 364) and Bochum recordings (n = 322, normal fetuses). fABAS of 48 recordings from fetuses with intra-uterine growth restriction (IUGR, Bochum) was reduced in most of the cases, a result consistent with IUGR fetuses from Jena previously reported. fABAS calculated from 5 min snapshots only partly covers the accuracy when compared to fABAS from 30 min recordings. More precise diagnosis requires longer recordings.fABAS obtained from fMCG recordings is a strong candidate for standardized assessment of functional maturation age and developmental disturbances. Even 5 min recordings seem to be valuable for screening for maturation problems.
Minimally Invasive Therapy & Allied Technologies | 2016
Dimitrios Panayotopoulos; Ibrahim Alkatout; Stefan Soltesz; Lieselotte Mettler; S. Schiermeier; Wolfgang Hatzmann; Günter Karl Noé
Abstract Introduction: Unprotected power morcellation can lead to a spread of previously undiagnosed malignancy. We present a new containment bag with two closable trocar insertion sites to reduce this risk. This pilot study was designed to assess the feasibility of this device under everyday conditions. Material and methods: The containment bag was used in ten laparoscopic supracervical hysterectomies. We evaluated time requirement for bag insertion into the abdominal cavity and in-bag morcellation. A 2000 ml polyurethane morcellation bag was used for all interventions. All surgeries were carried out in a three-trocar setting. Results: We carried out ten supracervical hysterectomies. No intraoperative complications and no bag ruptures occurred. The meantime requirement to insert the bag and prepare the specimen for morcellation was 10.5 min (range, 7–19 min). The mean specimen weight was 191.9 g (range, 32–710 g). Mean morcellation time was 10.5 min (range, 3–28 min), mean weight of remaining tissue and fluid in the bag after morcellation was 12.1 g (range, 7–19 g). Conclusions: The presented data demonstrate that the endobag can be successfully applied in the clinical routine. Further studies are required to evaluate additional characteristics, such as individual learning curve and time requirements.
Fetal Diagnosis and Therapy | 2008
S. Schiermeier; Peter Van Leeuwen; J. Reinhard; Dietrich Grönemeyer; Wolfgang Hatzmann
Background: Magnetocardiography and M-mode fetal echocardiography are non-invasive techniques capable of identifying fetal arrhythmias. The STAN®-fetal scalp electrode system can record the fetal echocardiogram in labor. Case: A patient was admitted to hospital with preterm contractions and cervical insufficiency at 28 weeks of gestation. After treatment with a β-sympathomimetic drug (Partusisten®) one fetus developed supraventricular tachycardia. After terminating the Partusisten medication, there was no effect on the fetal arrhythmia and flecainide therapy was initiated. Maintenance dosages controlled the condition thereafter. Cardiac time intervals of a fetus in labor can be presented, which did not change significantly throughout the first stage of labor. Conclusion: Flecainide is an effective therapy for supraventricular tachycardias in a twin pregancy. Analyzing the cardiac time intervals during pregnancy can improve perinatal outcome.
Nature Precedings | 2007
Martin Daumer; Michael Scholz; Anne-Laure Boulesteix; Stephanie Pildner von Steinburg; S. Schiermeier; Wolfgang Hatzmann; K. T. M. Schneider
Recording of fetal heart rate via CTG monitoring has been routinely performed as an important part of antenatal and subpartum care for several decades. The current guidelines of the FIGO (ref 1) recommend a normal range of the fetal heart rate from 110 to 150 bpm. However, there is no agreement in the medical community whether this is the correct range (ref 2). We aim to address this question by computerized analysis (ref 3) of a high quality database (HQDb, ref 4) of about one billion electronically registered fetal heart rate measurements from about 10,000 pregnancies in three medical centres over seven years. In the present paper, we lay out a detailed analysis plan for this evidence-based project in the vein of the validation policy of the Sylvia Lawry Centre for Multiple Sclerosis Research (ref 5) with a split of the database into an exploratory part and a part reserved for validation. We will perform the analysis and the validation after publication of this plan in order to reduce the probability of publishing false positive research findings (ref 6-7). ∗Sylvia Lawry Centre for MS Research, Munich, Germany †Trium Analysis Online GmbH, Munich, Germany ‡Department of Obstetrics and Gynecology, Technical University of Munich, Germany §Department of Obstetrics and Gynecology, University Witten/Herdecke, Germany 1 N at ur e P re ce di ng s : d oi :1 0. 10 38 /n pr e. 20 07 .9 80 .1 : P os te d 12 S ep 2 00 7
Tumor Biology | 2006
Gregor Westhof; Michael Olbrecht; Manfred H. Wolff; S. Schiermeier; Ralf C. Zimmermann; Wolfgang Hatzmann
We hypothesized that inclusion of p21WAF1, an indicator of biological function, into the p53 assay might improve the clinical value of p53 in breast cancer diagnosis.In primary breast carcinomas (n = 146) and healthy/benign controls (n = 40), the p53 protein was quantified by luminescence immunoassay. The p21 protein was simultaneously measured by quantitative ELISA in a representative subgroup of breast cancers (n = 52) and controls (n = 17). In controls, p53 but not p21 was detectable. In almost all cancer tissues, p53 and p21 expression could be quantified. There was no correlation between the concentrations of both proteins. However, if p53 exceeded a threshold of 1.0 ng/mg protein, p21 expression was significantly reduced compared with samples with p53 below threshold. p21 was normally distributed in the low-p53 subpopulation, but not in the high-p53 group. The histologic parameter ‘grade III’ was more often found (p = 0.002) in tumors with p53 >1.0 ng/mg protein than in those with p53 below the threshold. Histological criteria of high tumor malignancy were found more often in cases with high p53 but low p21. Consequently, in clinical routine, a quantitative double assay of p53 and p21WAF1 might help to discriminate breast cancers with preserved or impaired/lost p53 function.