Effects of a Mindfulness Intervention Comprising an App, Web-Based Workshops, and a Workbook on Perceived Stress Among Nurses and Nursing Trainees: Protocol for a Randomized Controlled Trial.

BACKGROUND: Previous research has found digitally supported mindfulness interventions to be effective when used for stress management among workers in high-stress occupations. Findings on digitally supported mindfulness interventions among nurses working in acute inpatient care settings are heterogeneous, lack long-term follow-up, and do not assess adherence and acceptability. OBJECTIVE: This study aimed to investigate the effectiveness and efficacy of a digitally supported mindfulness intervention designed to improve health- and work-related outcomes among nurses and nursing trainees working in acute inpatient care settings. METHODS: We will conduct a multicenter randomized controlled trial using a wait-list control group design. Randomization will be stratified by hospital and job status (nurse or nursing trainee). Recruitment will take place on the web and offline during the working hours of nurses and nursing trainees. The intervention group will receive a digitally supported mindfulness intervention, which will comprise an app, 2 web-based workshops, and a workbook, whereas the wait-list control group will be scheduled to receive the same intervention 14 weeks later. The 2 web-based workshops will be led by a certified mindfulness-based stress reduction trainer. Nurses will use the app and the workbook independently. Self-report web-based surveys will be conducted on the web at baseline, at 10 weeks after allocation, at 24 weeks after allocation, and at 38 weeks after allocation. Outcomes of interest will include perceived stress (primary outcome), health- and work-related variables, and variables related to adherence and acceptability of the digitally supported mindfulness intervention. We will perform intention-to-treat and per-protocol analyses. RESULTS: Data collection will be completed by the beginning of August 2022. Data analyses will be completed by December 2022. CONCLUSIONS: Our study design, including long-term follow-up and the investigation of variables related to adherence and acceptability, will ensure rigorous evaluation of effectiveness and efficacy. Relative to costly in-person intervention efforts, this program may present a cost-effective and potentially highly scalable alternative. Findings regarding effectiveness, efficacy, adherence, and acceptability will inform stakeholders' decisions regarding the implementation of similar interventions to promote the well-being of nurses and nursing trainees, which may, in turn, alleviate detrimental stress-related outcomes (eg, burnout) because of work-related demands. TRIAL REGISTRATION: German Clinical Trials Register DRKS00025997; https://tinyurl.com/433cas7u. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/37195.

Early Start of Infliximab in Crohn's Disease Increases Rates of Endoscopic Remission and Decreases Stenosis Formation: Experiences From a Single Center Cohort.

Background: Over 10 years ago, the step-up/top-down trial demonstrated favorable outcomes of Crohn's disease (CD) after early initiation of infliximab (IFX) in patients with CD. However, data on long-term effects of this treatment strategy in daily clinical practice are scarce. Methods: This retrospective study investigated effects of early (<24 months after diagnosis) versus late intervention (>24 months) of IFX in CD on endoscopic remission (ER) rates, surgery rates, and course of CD, long term. Results: Overall, 242 CD patients (94 early, 148 late intervention) were started on IFX and followed for 24 months. Sixty-one patients with early and 86 with late intervention underwent endoscopy after start of IFX. After IFX induction, 90.3% of patients with early versus 87.8% with late intervention were in clinical remission (P = .676), compared to 89.1% versus 85.8% after 24 months (P = .554). Almost half of patients with early IFX (45.9%, n = 28/61) achieved ER within 24 months compared to only one forth with late IFX intervention (25.6%, n = 22/86, P = .013). In addition, significantly less patients with early IFX intervention (9.8%, n = 6/61) developed intestinal stenosis during 24 months follow-up compared to late IFX start (29.1%, n = 25/86, P = .007). Logistic regression revealed early IFX intervention as only relevant factor achieving ER with an odds ratio of 2.386 (95% confidence interval [1.1180; 4.825], P = .016). Conclusions: Our data on early IFX therapy in CD support early IFX intervention with more patients achieving ER, and less patients developing stricturing disease behavior. Early IFX intervention could therefore change the course of CD.

Effects of an Integrative Mind-Body-Medicine Group Program on Breast Cancer Patients During Chemotherapy: An Observational Study.

BACKGROUND: Breast cancer is one of the leading cancers in women in the Western world. Cancer treatment, especially chemotherapy, is often associated with physical and psychosocial side effects. OBJECTIVE: To improve the quality of life and manage side effects, a new integrative mind-body-medicine group concept for breast cancer patients receiving chemotherapy was developed and pilot tested. METHODS: Breast cancer patients participated in a 66 hours mind-body-medicine group program tailored to the needs of cancer patients during chemotherapy. The program was integrated into standard care encompassing mindfulness training, yoga, moderate exercise, nutrition, complementary self-help strategies, cognitive restructuring, and acupuncture. Quality of life (EORTC QLQ-C30), depression and anxiety (HADS), stress (PSS-10), and fatigue (BFI) were assessed before and after the program, as well as satisfaction and safety. Analyses were carried out on exploratory basis with paired samples t-tests. RESULTS: Fifty-seven female patients, aged 51.3±10.5 years, with breast cancer diagnoses were enrolled. After completing the program, global EORTC quality of life was improved (D=9.5; 95%-CI=[2.9|16.1]; p=.005), although the EORTC-symptom scales assessing fatigue (D=9.9; 95%-CI=[1|18.8]; p=.030), nausea (D=7.1; 95%- CI=[0.6|13.6]; p=.031), and dyspnea (D=12.5; 95%-CI=[2.9|22.1]; p=.011) were found to be increased. Stress (D=-3.5; 95%-CI=[-5|-2.1]; p=.000), anxiety (D=-3.8; 95%-CI=[-4.9|-2.7]; p=.000) and depression (D=-3.9; 95%-CI=[-4.9|-2.8]; p=.000) were also found to be significantly reduced. Regarding the severity of (D=0.2; 95%- CI=[-0.8|0.5]; p=.644) and the impairment due to fatigue (D=0.1; 95%-CI=[-0.8|0.6]; p=.696), no significant worsening was observed. Patients were satisfied with the program. No serious adverse events were reported. CONCLUSION: Breast cancer patients benefit from an integrative mind-body-medicine group program during chemotherapy regarding the quality of life and psychological symptoms. Randomized controlled trials are warranted.

Yoga for improving health-related quality of life, mental health and cancer-related symptoms in women diagnosed with breast cancer.

BACKGROUND: Breast cancer is the cancer most frequently diagnosed in women worldwide. Even though survival rates are continually increasing, breast cancer is often associated with long-term psychological distress, chronic pain, fatigue and impaired quality of life. Yoga comprises advice for an ethical lifestyle, spiritual practice, physical activity, breathing exercises and meditation. It is a complementary therapy that is commonly recommended for breast cancer-related impairments and has been shown to improve physical and mental health in people with different cancer types. OBJECTIVES: To assess effects of yoga on health-related quality of life, mental health and cancer-related symptoms among women with a diagnosis of breast cancer who are receiving active treatment or have completed treatment. SEARCH METHODS: We searched the Cochrane Breast Cancer Specialised Register, MEDLINE (via PubMed), Embase, the Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 1), Indexing of Indian Medical Journals (IndMED), the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) search portal and Clinicaltrials.gov on 29 January 2016. We also searched reference lists of identified relevant trials or reviews, as well as conference proceedings of the International Congress on Complementary Medicine Research (ICCMR), the European Congress for Integrative Medicine (ECIM) and the American Society of Clinical Oncology (ASCO). We applied no language restrictions. SELECTION CRITERIA: Randomised controlled trials were eligible when they (1) compared yoga interventions versus no therapy or versus any other active therapy in women with a diagnosis of non-metastatic or metastatic breast cancer, and (2) assessed at least one of the primary outcomes on patient-reported instruments, including health-related quality of life, depression, anxiety, fatigue or sleep disturbances. DATA COLLECTION AND ANALYSIS: Two review authors independently collected data on methods and results. We expressed outcomes as standardised mean differences (SMDs) with 95% confidence intervals (CIs) and conducted random-effects model meta-analyses. We assessed potential risk of publication bias through visual analysis of funnel plot symmetry and heterogeneity between studies by using the Chi2 test and the I2 statistic. We conducted subgroup analyses for current treatment status, time since diagnosis, stage of cancer and type of yoga intervention. MAIN RESULTS: We included 24 studies with a total of 2166 participants, 23 of which provided data for meta-analysis. Thirteen studies had low risk of selection bias, five studies reported adequate blinding of outcome assessment and 15 studies had low risk of attrition bias.Seventeen studies that compared yoga versus no therapy provided moderate-quality evidence showing that yoga improved health-related quality of life (pooled SMD 0.22, 95% CI 0.04 to 0.40; 10 studies, 675 participants), reduced fatigue (pooled SMD -0.48, 95% CI -0.75 to -0.20; 11 studies, 883 participants) and reduced sleep disturbances in the short term (pooled SMD -0.25, 95% CI -0.40 to -0.09; six studies, 657 participants). The funnel plot for health-related quality of life was asymmetrical, favouring no therapy, and the funnel plot for fatigue was roughly symmetrical. This hints at overall low risk of publication bias. Yoga did not appear to reduce depression (pooled SMD -0.13, 95% CI -0.31 to 0.05; seven studies, 496 participants; low-quality evidence) or anxiety (pooled SMD -0.53, 95% CI -1.10 to 0.04; six studies, 346 participants; very low-quality evidence) in the short term and had no medium-term effects on health-related quality of life (pooled SMD 0.10, 95% CI -0.23 to 0.42; two studies, 146 participants; low-quality evidence) or fatigue (pooled SMD -0.04, 95% CI -0.36 to 0.29; two studies, 146 participants; low-quality evidence). Investigators reported no serious adverse events.Four studies that compared yoga versus psychosocial/educational interventions provided moderate-quality evidence indicating that yoga can reduce depression (pooled SMD -2.29, 95% CI -3.97 to -0.61; four studies, 226 participants), anxiety (pooled SMD -2.21, 95% CI -3.90 to -0.52; three studies, 195 participants) and fatigue (pooled SMD -0.90, 95% CI -1.31 to -0.50; two studies, 106 participants) in the short term. Very low-quality evidence showed no short-term effects on health-related quality of life (pooled SMD 0.81, 95% CI -0.50 to 2.12; two studies, 153 participants) or sleep disturbances (pooled SMD -0.21, 95% CI -0.76 to 0.34; two studies, 119 participants). No trial adequately reported safety-related data.Three studies that compared yoga versus exercise presented very low-quality evidence showing no short-term effects on health-related quality of life (pooled SMD -0.04, 95% CI -0.30 to 0.23; three studies, 233 participants) or fatigue (pooled SMD -0.21, 95% CI -0.66 to 0.25; three studies, 233 participants); no trial provided safety-related data. AUTHORS' CONCLUSIONS: Moderate-quality evidence supports the recommendation of yoga as a supportive intervention for improving health-related quality of life and reducing fatigue and sleep disturbances when compared with no therapy, as well as for reducing depression, anxiety and fatigue, when compared with psychosocial/educational interventions. Very low-quality evidence suggests that yoga might be as effective as other exercise interventions and might be used as an alternative to other exercise programmes.

Yoga for breast cancer patients and survivors: a systematic review and meta-analysis.

BACKGROUND: Many breast cancer patients and survivors use yoga to cope with their disease. The aim of this review was to systematically assess and meta-analyze the evidence for effects of yoga on health-related quality of life and psychological health in breast cancer patients and survivors. METHODS: MEDLINE, PsycInfo, EMBASE, CAMBASE, and the Cochrane Library were screened through February 2012. Randomized controlled trials (RCTs) comparing yoga to controls were analyzed when they assessed health-related quality of life or psychological health in breast cancer patients or survivors. Risk of bias was assessed using the Cochrane risk of bias tool. Standardized mean differences (SMD) and 95% confidence intervals (CI) were calculated. RESULTS: Twelve RCTs with a total of 742 participants were included. Seven RCTs compared yoga to no treatment; 3 RCTs compared yoga to supportive therapy; 1 RCT compared yoga to health education; and 1 RCT compared a combination of physiotherapy and yoga to physiotherapy alone. Evidence was found for short-term effects on global health-related quality of life (SMD = 0.62 [95% CI: 0.04 to 1.21]; P = 0.04), functional (SMD = 0.30 [95% CI: 0.03 to 0.57), social (SMD = 0.29 [95% CI: 0.08 to 0.50]; P < 0.01), and spiritual well-being (SMD = 0.41 [95% CI: 0.08; 0.74]; P = 0.01). These effects were, however, only present in studies with unclear or high risk of selection bias. Short-term effects on psychological health also were found: anxiety (SMD = -1.51 [95% CI: -2.47; -0.55]; P < 0.01), depression (SMD = -1.59 [95% CI: -2.68 to -0.51]; P < 0.01), perceived stress (SMD = -1.14 [95% CI:-2.16; -0.12]; P = 0.03), and psychological distress (SMD = -0.86 [95% CI:-1.50; -0.22]; P < 0.01). Subgroup analyses revealed evidence of efficacy only for yoga during active cancer treatment but not after completion of active treatment. CONCLUSIONS: This systematic review found evidence for short-term effects of yoga in improving psychological health in breast cancer patients. The short-term effects on health-related quality of life could not be clearly distinguished from bias. Yoga can be recommended as an intervention to improve psychological health during breast cancer treatment.

Modeling fetal--maternal heart-rate interaction.

The influence of maternal respiration on the occurrence of short-term fetal--maternal heart-rate coordination was examined using a model, which considers both heart-rate characteristics and effects of maternal respiratory sinus arrhythmia. Epochs of fetal--maternal heart-rate coordination were identified in model data produced at varying respiratory rates and compared with epochs found in real data acquired in mother-fetus pairs. The model results suggest that the low incidence of epochs found in the real data at low-breathing rates may be explained by heart-rate characteristics, but that the higher incidence at fast rates must be due to other factors.

Influence of gestational age on the effectiveness of spatial and temporal methods for the reconstruction of the fetal magnetocardiogram.

Fetal magnetocardiography (fMCG) has been shown to augment fetal ultrasound evaluation for high-risk conditions, but the clinical utility of fMCG depends on the reliability of the cardiac traces reconstructed. We performed a methodological study to examine the influence of gestational age on the properties of the fetal magnetocardiograms extracted with two methods of signal reconstruction: the template matching technique (TMT), which extracts the maternal components from the signal using only temporal information, and independent component analysis (ICA), which separates the fetal signals by using information on the spatial distribution of the mixed source signals in addition to higher order temporal statistics. Efficiency and accuracy were evaluated in terms of fetal beat detection, signal characteristics, and duration of cardiac time intervals (CTIs) on the averaged traces. ICA outperformed TMT with regard to beat detection and signal-to-noise ratio. The timing of the heartbeats and the duration of the CTIs were essentially the same, whereas some alterations in signal morphology were observed in the ICA traces. We conclude that ICA may be useful in early gestation when the signals are noisy, while TMT may be preferred when accurate beat morphology is required for diagnostic purposes.

Heart rate features in fetal behavioural states.

BACKGROUND AND AIM: Fetal behavioural states have been defined on the basis of eye movements, body movements and heart rate patterns as presented by cardiotocography (CTG). The aim of this work was to determine whether behavioural states can be distinguished on the basis of heart rate features alone using high resolution beat-to-beat fetal magnetocardiography. STUDY DESIGN: Five minute magnetocardiograms were recorded at a sampling rate of 1 kHz in 40 healthy fetuses (36th-41st week of gestation). In the reconstructed RR interval time series, 256-beat epochs corresponding to the behavioural states 1F, 2F and 4F were visually identified according to heart rate patterns as defined for CTG. These epochs were then quantified using mean RR interval, its standard deviation (SDNN), its root mean square of successive difference (RMSSD) and on the basis of symbolic dynamics of short 8 beat trains. RESULTS: Pairwise comparison between the behavioural states showed that the values of each of these measures differed significantly between the states. Quadratic discriminant analysis further revealed that mean RR interval and SDNN sufficed to classify state with a correct classification of 92%. CONCLUSIONS: The results suggest that measures that quantify overall aspects of heart rate can distinguish RR interval time series which were classified into different fetal behavioural states. The differences in short-term variability as quantified by RMSSD and symbolic dynamics may help reveal new aspects of these states.

Effect of prenatal antiarrhythmic treatment on cardiac function in a twin pregnancy.

We present a case of supraventricular tachycardia affecting one fetus in a twin pregnancy. Before and after treatment with flecainide and cardioversion, we examined conduction times and heart rate variability (HRV) in both twins on the basis of magnetocardiography. Cardiac conduction times increased in both fetuses but HRV showed opposing effects with a number of HRV measures. This case demonstrates that magnetocardiography not only enables identification of fetal arrhythmia, but also permits the investigation of the effects of antiarrhythmic treatment on the conductive system as well as on interaction with the autonomic nervous system.

Quantification of cardiac magnetic field orientation during ventricular de- and repolarization.

We compared the stability and discriminatory power of different methods of determining cardiac magnetic field map (MFM) orientation within the context of coronary artery disease (CAD). In 27 healthy subjects and 24 CAD patients, multichannel magnetocardiograms were registered at rest. MFM orientation was determined during QT interval using: (a) locations of the positive and negative centres-of-gravity, (b) locations of the field extrema and (c) the direction of the maximum field gradient. Deviation from normal orientation quantified the ability of each approach to discriminate between healthy and CAD subjects. Although the course of orientation was similar for all methods, receiver operating characteristic analysis showed the best discrimination of CAD patients for the centre-of-gravity approach (area-under-the-curve = 86%), followed by the gradient (84%) and extrema (76%) methods. Consideration of methodological and discriminatory advantages with respect to noninvasive diagnosis of CAD suggests that the centres-of-gravity method is the most suited one.

[STEMI network Essen--results after 1 year]. / Herzinfarktverbund Essen: Ergebnisse nach 1 Jahr.

The myocardial infarction network "Herzinfarktverbund Essen" was initiated on September 1, 2004 in order to establish a standardized strategy and therapy for patients with ST elevation myocardial infarction (STEMI) in the city of Essen. The primary goal is the immediate reopening of the infarcted vessel by direct transfer of the patient to a hospital with 24-h stand-by catheter laboratory. The first 1-year follow-up, completed on August 31, 2006, showed a low 1-year mortality rate (11.2%), whereby 7.6% of the patients died in hospital. There was a significant dependency of mortality on age, the prehospital stability of cardiovascular circulation, the amount of left ventricular damage, the TIMI flow after intervention, and the duration of interventional therapy ("puncture-to-balloon" time). The coronary status, anticoagulation therapy as well as diabetes mellitus were also dependent variables, whereas the type of stent showed no influence. The rate of restenosis was greater with bare-metal stents (BMS) compared to the use of drug-eluting stents (DES). There was a low rate of repeated STEMI or NSTEMI (non-ST elevation myocardial infarction; 1.8%, 1.7%). These first long-term data confirm the successful implementation of treatment guidelines for STEMI patients within a standardized strategy in an urban environment.

Heart rate variability in the fetus: a comparison of measures.

BACKGROUND: In fetal surveillance, fetal heart rate changes are assessed using cardiotocography (CTG). Standard procedures used in the quantification of heart rate variability (HRV) are seldom applied as CTG does not deliver beat interval durations with the same accuracy as the electrocardiogram (ECG). Thus little is known about the interdependency of standard HRV measures prenatally. MATERIALS AND METHODS: Using fetal magnetocardiography (FMCG: the magnetic equivalent of the fetal ECG), we investigated standard HRV measures in a homogenous group of 20 healthy fetuses. Ten HRV measures were analyzed in 60 five-minute RR interval time series derived from FMCG acquisitions (16th-40th week of gestation). RESULTS: Using regression analysis, we found a clear dependency on gestational age and mean RR interval for measures from the time and frequency domains as well as for a measure for complexity. Correlation analysis revealed a strong interdependency of the measures, in particular within the specific domains. An adequate description of fetal HRV may be achieved using the standard deviation from the time domain, the high frequency band (0.15-0.40 Hz) from the frequency domain and approximate entropy as a complexity measure. CONCLUSION: The results indicate that different characteristics of fetal HRV are embedded in the different domains.

MR imaging of the uterus and cervix in healthy women: determination of normal values.

The purpose of this study was to establish normal values for the volume of the uterus and cervix in MRI based on age and the menstrual cycle phase. We performed MRI of the pelvis in 100 healthy women. For the uterus, they were further divided into two groups: one with myomas and/or adenomyosis and one without either. The volume of the uterus and cervix and thickness of the uterine wall layers were analysed by age and the menstrual cycle phase. The mean volume of the uterus in both groups and the cervix significantly increased with age to reach its peak at 41-50 years, and then dropped. Likewise, the thickness of the endometrium and the junctional zone, but not the myometrium, significantly increased until 41-50 years, and then decreased. When we compared the volume of the uterus and cervix and the thickness of the uterine wall layers between the two phases of the menstrual cycle, we found no significant differences. The volume of the uterus and cervix and the thickness of the endometrium and junctional zone differ significantly with age, but not between the two phases of the menstrual cycle. Knowledge of MRI-related normal values can be expected to aid the early identification of uterine pathologies.

Regular heartbeat dynamics are associated with cardiac health.

The human heartbeat series is more variable and, hence, more complex in healthy subjects than in congestive heart failure (CHF) patients. However, little is known about the complexity of the heart rate variations on a beat-to-beat basis. We present an analysis based on symbolic dynamics that focuses on the dynamic features of such beat-to-beat variations on a small time scale. The sequence of acceleration and deceleration of eight successive heartbeats is represented by a binary sequence consisting of ones and zeros. The regularity of such binary patterns is quantified using approximate entropy (ApEn). Holter electrocardiograms from 30 healthy subjects, 15 patients with CHF, and their surrogate data were analyzed with respect to the regularity of such binary sequences. The results are compared with spectral analysis and ApEn of heart rate variability. Counterintuitively, healthy subjects show a large amount of regular beat-to-beat patterns in addition to a considerable amount of irregular patterns. CHF patients show a predominance of one regular beat-to-beat pattern (alternation of acceleration and deceleration), as well as some irregular patterns similar to the patterns observed in the surrogate data. In healthy subjects, regular beat-to-beat patterns reflect the physiological adaptation to different activities, i.e., sympathetic modulation, whereas irregular patterns may arise from parasympathetic modulation. The patterns observed in CHF patients indicate a largely reduced influence of the autonomic nervous system. In conclusion, analysis of short beat-to-beat patterns with respect to regularity leads to a considerable increase of information compared with spectral analysis or ApEn of heart-rate variations.

Increase in regularity of fetal heart rate variability with age.

It is generally assumed that fetal heart rate variability increases with gestation, reflecting prenatal development of the autonomic nervous system. We examined standard measures quantifying fetal heart rate variability, as well as a complexity measure, approximate entropy, in 66 fetal magnetocardiograms recorded from 22 healthy pregnant women between the 16th and 42nd week of gestation. In particular, regularity in the fetal RR interval time series was assessed on the basis of symbolic dynamics. The results showed that, beside an overall increase in fetal heart rate variability and complexity during pregnancy, there was also an increase in specific sets of binary patterns with low approximate entropy, i.e., a high degree of regularity. These sets were characterized by short epochs of heart rate acceleration and deceleration, and comparison with surrogate data confirmed that their random occurrence is rare. The results most likely reflect the influence of increasingly differentiated fetal behavioral states and transitions between them in association with fetal development.

Identification of patients with coronary artery disease using magnetocardiographic signal analysis.

INTRODUCTION: Magnetocardiography (MCG), which measures the magnetic component of the heart's electrical activity, offers an alternative approach for analyzing changes induced by coronary artery disease (CAD). This study examines several parameters that quantify spatial and temporal aspects of cardiac magnetic signals in CAD. MATERIALS AND METHODS: MCGs were registered at rest in 144 subjects, aged 58.3 +/- 9.8 years: 50 healthy subjects, 43 CAD patients without myocardial infarction (MI), 36 with MI, and 15 with spontaneous episodes of ventricular tachycardia (VT). Spatial characteristics of magnetic field maps (MFM), quantified using their centers of gravity, included MFM orientation and trajectory plots. Spatio-temporal analysis was performed by determining the spatial distribution of the QT interval. RESULTS: In CAD patients, MFM orientation during the QT interval deviated from normal in 67% of patients without MI and in 85% of patients with MI. Trajectory plots deviated from those of the normal group, with deviation increasing with disease severity. Quantifying the distribution of QT interval duration using a smoothness index demonstrated a significant difference between the values for healthy subjects and non-MI patients, as well as MI patients with and without VT (p < 0.001). CONCLUSION: The results reported demonstrate that disturbances in cardiac electrogenesis resulting from CAD may be assessed using MCG signal analysis.

Gender-related changes in magnetocardiographically determined fetal cardiac time intervals in intrauterine growth retardation.

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.

A quantitative comparison of different methods to detect cardiorespiratory coordination during night-time sleep.

BACKGROUND: The univariate approaches used to analyze heart rate variability have recently been extended by several bivariate approaches with respect to cardiorespiratory coordination. Some approaches are explicitly based on mathematical models which investigate the synchronization between weakly coupled complex systems. Others use an heuristic approach, i.e. characteristic features of both time series, to develop appropriate bivariate methods. OBJECTIVE: In this study six different methods used to analyze cardiorespiratory coordination have been quantitatively compared with respect to their performance (no. of sequences with cardiorespiratory coordination, no. of heart beats coordinated with respiration). Five of these approaches have been suggested in the recent literature whereas one method originates from older studies. RESULTS: The methods were applied to the simultaneous recordings of an electrocardiogram and a respiratory trace of 20 healthy subjects during night-time sleep from 0:00 to 6:00. The best temporal resolution and the highest number of coordinated heart beats were obtained with the analysis of 'Phase Recurrences'. Apart from the oldest method, all methods showed similar qualitative results although the quantities varied between the different approaches. In contrast, the oldest method detected considerably fewer coordinated heart beats since it only used part of the maximum amount of information available in each recording. CONCLUSIONS: The method of 'Phase Recurrences' should be the method of choice for the detection of cardiorespiratory coordination since it offers the best temporal resolution and the highest number of coordinated sequences and heart beats. Excluding the oldest method, the results of the heuristic approaches may also be interpreted in terms of the mathematical models.

Dependency of magnetocardiographically determined fetal cardiac time intervals on gestational age, gender and postnatal biometrics in healthy pregnancies.

BACKGROUND: Magnetocardiography enables the precise determination of fetal cardiac time intervals (CTI) as early as the second trimester of pregnancy. It has been shown that fetal CTI change in course of gestation. The aim of this work was to investigate the dependency of fetal CTI on gestational age, gender and postnatal biometric data in a substantial sample of subjects during normal pregnancy. METHODS: A total of 230 fetal magnetocardiograms were obtained in 47 healthy fetuses between the 15th and 42nd week of gestation. In each recording, after subtraction of the maternal cardiac artifact and the identification of fetal beats, fetal PQRST courses were signal averaged. On the basis of therein detected wave onsets and ends, the following CTI were determined: P wave, PR interval, PQ interval, QRS complex, ST segment, T wave, QT and QTc interval. Using regression analysis, the dependency of the CTI were examined with respect to gestational age, gender and postnatal biometric data. RESULTS: Atrioventricular conduction and ventricular depolarization times could be determined dependably whereas the T wave was often difficult to detect. Linear and nonlinear regression analysis established strong dependency on age for the P wave and QRS complex (r2 = 0.67, p < 0.001 and r2 = 0.66, p < 0.001) as well as an identifiable trend for the PR and PQ intervals (r2 = 0.21, p < 0.001 and r2 = 0.13, p < 0.001). Gender differences were found only for the QRS complex from the 31st week onward (p < 0.05). The influence on the P wave or QRS complex of biometric data, collected in a subgroup in whom recordings were available within 1 week of birth, did not display statistical significance. CONCLUSION: We conclude that 1) from approximately the 18th week to term, fetal CTI which quantify depolarization times can be reliably determined using magnetocardiography, 2) the P wave and QRS complex duration show a high dependency on age which to a large part reflects fetal growth and 3) fetal gender plays a role in QRS complex duration in the third trimester. Fetal development is thus in part reflected in the CTI and may be useful in the identification of intrauterine growth retardation.