Oral intake of solid medications in patients with post-stroke dysphagia. A challenge for nurses?

AIM: To provide a comprehensive overview of how stroke nurses manage solid medication (SM) delivery to patients with post-stroke dysphagia. DESIGN: Cross-sectional study. METHODS: A self-administered online survey was carried out among nurses in German-speaking countries between September and December 2021. RESULTS: Out of a total of 754 responses, analysis was conducted on 195 nurses who reported working on a stroke unit. To identify swallowing difficulties in acute stroke care, 99 nurses indicated routinely administering standardised screenings, while 10 use unvalidated screenings, and 82 are waiting for a specialist evaluation. Regardless of whether screening methods are used or not, most preferred a non-oral route of medication administration for patients with suspected dysphagia. None of the respondents reported administering whole SMs orally to patients. If screening methods indicate dysphagia, approximately half of the respondents would modify SMs. Participants who stated to use the Gugging Swallowing Screen managed the SM intake guided by its severity levels. One-third of the group who awaited assessment by the dysphagia specialist provided modified medication before the consultation. CONCLUSION: Most of the nurses on stroke units use swallowing screens and avoid the administration of whole SMs in post-stroke dysphagia. In addition to the non-oral administration, SMs are modified if dysphagia is suspected. Precise guidance on the administration of SM is needed, based on screening tests and prior to expert consultation. TRIAL AND PROTOCOL REGISTRATION: ClinicalTrials.gov: Registration ID: NCT05173051/ Protocol ID: 11TS003721. IMPLICATIONS FOR THE PROFESSION AND/OR PATIENT CARE: The present paper serves to alert nurses to the issue of patient safety when administering medication for acute stroke-induced dysphagia. IMPACT: SM delivery after acute stroke-induced dysphagia is often neglected. While nurses are aware of the risk associated with dysphagia and would not give whole SMs to patients, the modification of tablets and their administration with semisolids are common. REPORTING METHOD: This study was reported according to the Checklist for Reporting of Survey Studies (CROSS).

Baroreflex activity through the analysis of the cardio-respiratory variability influence over blood pressure in cardiomyopathy patients.

A large portion of the elderly population are affected by cardiovascular diseases. Early prognosis of cardiomyopathies remains a challenge. The aim of this study was to classify cardiomyopathy patients by their etiology based on significant indexes extracted from the characterization of the baroreflex mechanism in function of the influence of the cardio-respiratory activity over the blood pressure. Forty-one cardiomyopathy patients (CMP) classified as ischemic (ICM-24 patients) and dilated (DCM-17 patients) were considered. In addition, thirty-nine control (CON) subjects were used as reference. The beat-to-beat (BBI) time series, from the electrocardiographic (ECG) signal, the systolic (SBP), and diastolic (DBP) time series, from the blood pressure signal (BP), and the respiratory time (TT), from the respiratory flow (RF) signal, were extracted. The three-dimensional representation of the cardiorespiratory and vascular activities was characterized geometrically, by fitting a polygon that contains 95% of data, and by statistical descriptive indices. DCM patients presented specific patterns in the respiratory response to decreasing blood pressure activity. ICM patients presented more stable cardiorespiratory activity in comparison with DCM patients. In general, CMP shown limited ability to regulate changes in blood pressure. In addition, patients also shown a limited ability of their cardiac and respiratory systems response to regulate incremental changes of the vascular variability and a lower heart rate variability. The best classifiers were used to build support vector machine models. The optimal model to classify ICM versus DCM patients achieved 92.7% accuracy, 94.1% sensitivity, and 91.7% specificity. When comparing CMP patients and CON subjects, the best model achieved 86.2% accuracy, 82.9% sensitivity, and 89.7% specificity. When comparing ICM patients and CON subjects, the best model achieved 88.9% accuracy, 87.5% sensitivity, and 89.7% specificity. When comparing DCM patients and CON subjects, the best model achieved 87.5% accuracy, 76.5% sensitivity, and 92.3% specificity. In conclusion, this study introduced a new method for the classification of patients by their etiology based on new indices from the analysis of the baroreflex mechanism.

Improving fertilizer response of crop yield through liming and targeting to landscape positions in tropical agricultural soils.

Nutrient management research was conducted across locations to investigate the influence of landscape position (hill, mid-, and foot slope) in teff (Eragrostis tef) and wheat (Triticum aestivum) yield response to fertilizer application and liming in the 2018 and 2019 cropping seasons. The treatments included 1) NPS fertilizer as a control treatment (42 N + 10P + 4.2S kg ha-1 for teff and 65 N + 20P + 8.5S kg ha-1 for wheat); 2) NPS and potassium (73 N + 17P + 7.2S + 24 K kg ha-1 for teff and 103 N + 30P + 12.7S + 24 K kg ha-1 for wheat) and 3) NPSK and zinc (73 N + 17P + 7.2S + 24K + 5.3Zn kg ha-1 for teff and 103 N + 30P + 12.7S + 24K + 5,3Zn kg ha-1 for wheat) in acid soils with and without liming. Results showed that the highest teff and wheat grain yields of 1512 and 4252 kg ha-1 were obtained at the foot slope position, with the respective yield increments of 71% and 57% over the hillslope position. Yield response to fertilizer application significantly decreased with increasing slope owing to the decrease in soil organic carbon and soil water content and the increase in soil acidity. The application of lime with NPSK and NPSKZn fertilizer increased teff and wheat yields by 43-54% and 32-35%, respectively compared to the application of NPS fertilizer without liming where yield increments were associated with the application of N and P nutrients. Orthogonal contrasts revealed that landscape position, fertilizer application, and their interaction effects were significant on teff and wheat yields. Soil properties including soil pH, organic carbon, total N, and soil water content were increased down the slope, which might be attributed to sedimentation down the slope. However, available P is yet very low both in acidic and non-acidic soils. We conclude that crop response to applied nutrients could be enhanced by targeting nutrient management practices to agricultural landscape features and addressing other yield-limiting factors such as soil acidity and nutrient availability by conducting further research.

Novel dalbavancin-PLLA implant coating prevents hematogenous Staphylococcus aureus infection in a minimally invasive mouse tail vein model.

Infective/bacterial endocarditis is a rare but life-threatening disease with a hospital mortality rate of 22.7% and a 1-year mortality rate of 40%. Therefore, continued research efforts to develop efficient anti-infective implant materials are of the utmost importance. Equally important is the development of test systems that allow the performance of new materials to be comprehensively evaluated. In this study, a novel antibacterial coating based on dalbavancin was tested in comparison to rifampicin/minocycline, and the suitability of a recently developed mouse tail vein model for testing the implant coatings was validated. Small polymeric stent grafts coated with a poly-L-lactic acid (PLLA) layer and incorporated antibiotics were colonized with Staphylococcus (S.) aureus before implantation into the tail vein of mice. The main assessment criteria were the hematogenous spread of the bacteria and the local tissue reaction to the contaminated implant. For this purpose, colony-forming units (CFU) in the blood, spleen and kidneys were determined. Tail cross sections were prepared for histological analysis, and plasma cytokine levels and expression values of inflammation-associated genes were examined. Both antibiotic coatings performed excellently, preventing the onset of infection. The present study expands the range of available methods for testing the anti-infectivity of cardiovascular implants, and the spectrum of agents for effective surface coating.

Recurrence Plot-based Classification of Ischemic and Dilated Cardiomyopathy Patients.

A large portion of the elderly population are affected by cardiovascular diseases. The early prognosis of cardiomyopathies is still a challenge. The aim of this study was to classify cardiomyopathy patients by their etiology in function of significant indexes extracted from the characterization of the recurrence plot of the systems involved. Thirty-nine cardiomyopathy patients (CMP) classified as ischemic (ICM - 24 patients) and dilated (DCM-15 patients) were considered. In addition, thirty-nine control subjects (CON) were used as reference. The beat-to-beat (BBI) time series, from the electrocardiographic signal, the systolic (SBP), and diastolic (DBP) time series, from the blood pressure signal, and the respiratory time (FLW) from the respiratory flow signal, were extracted. The recurrence plot from each signal considered were calculated and characterized by a total of 12 indexes. The best classifiers were used to build support vector machine models. The optimal model to classify ICM versus DCM patients achieved 92.3% accuracy, 95.8% sensitivity, and 86.6% specificity. When comparing CMP patients and CON subjects, the best model achieved 85.8% accuracy, 92.3% sensitivity, and 80.1% specificity. Our results suggest a more deterministic behavior in DCM patients. Clinical Relevance - This study explores the recurrence plot for the classification of ICM and DCM patients.

Randomized Pilot Trial Using External Yarrow Liver Compress Applications With Metastatic Cancer Patients Suffering From Fatigue: Evaluation of Sympathetic Modulation by Heart Rate Variability Analysis.

BACKGROUND: Liver compresses are commonly applied in complementary medicine during cancer treatment and are believed to have an energizing effect. We conducted a pilot study to investigate the influence of external application of yarrow liver compresses on the autonomous nervous system by analyzing the heart rate variability (HRV) in metastatic cancer patients undergoing radiation therapy and suffering from cancer-related fatigue (CRF). METHODS: A randomized pilot trial was undertaken with patients suffering from CRF receiving palliative radiation therapy for bone or brain metastasis over 2 weeks. CRF patients were randomized into an intervention group receiving yarrow liver compresses and a control group receiving no external application. HRV was analyzed at the beginning (T1) and end (T2) period of the study during daytime (d) and nighttime (n) in both groups and quantified using time-, frequency-, and nonlinear dynamics domains. RESULTS: A total of 39 patients were randomized between September 2017 and August 2019 and a total of 20 patients (10 per group) were available for analysis. For both groups, significant differences in HRV analyses were found in the comparison over the timeline between the first and second measurement (T1d→T2d) during daytime. Specifically, the intervention group showed decreased HRV and complexity of heart rate regulation, indicating increased sympathetic activity at time T2d, whereas the control group showed increased HRV and complexity of heart rate regulation, indicating increased vagal activity at time T2d. Furthermore, the observed HRV analyses showed almost no significant differences between the 2 groups in a direct comparison at the beginning and the end of the study (exception: T2d). CONCLUSIONS: Yarrow liver compresses led to increased sympathetic activity during daytime in the intervention group, whereas in the control group, which did not receive any external application, increased parasympathetic activity was observed.

[Tasteless thickening agents? A competitive comparison]. / Geschmacksneutrale Andickungsmittel? ­ Ein kompetitiver Vergleich.

BACKGROUND: Thickening of drinks is a standard procedure in dysphagia therapy. Among other things, this adaptive procedure aims to prevent posterior leakage and reduce the demands placed on retarded swallowing reflexes by decelerating boluses. Studies show that taste perception can induce a negative attitude towards thickened fluids in patients. This study investigates whether different thickeners differ in taste. METHODS: The taste of eight arbitrarily chosen thickeners available on the German market were compared by 37 healthy adults. In the test setting, two thickeners combined with water competed against each other. Participants decided which one they preferred. Up to seven pairwise comparisons were performed by each participant. Overall, 224 comparisons were carried out. Based on these results, a relative taste grade was calculated using a probabilistic model and significance tests for differences were performed. RESULTS AND CONCLUSION: There are significant differences in taste between the different products, presumably depending on their respective basic ingredients. To respect individual patient's preferences, different thickeners should be tried out in dysphagia therapy. It remains unclear whether thickeners' taste differences remain relevant once other liquids such as coffee, tea, or juice are thickened.

Quantification of Cardiovascular Regulation Applying Heart Rate Variability Analyses for Different Warm and Moist Chest Compresses in Healthy Subjects.

Background: In integrative medicine, complementary healing methods, such as external applications (massages, rhythmic rubs, and compresses), are part of the practice and clinical application and have proven their therapeutic effect in various fields. Objective: Aim of this exploratory, controlled, single-blinded study was to investigate the effects of three different warming chest compresses on cardiovascular regulation by analyzing heart rate variability (HRV) in healthy subjects. Methods: Over a period of 4 weeks, three different warming chest compresses (a hot water compress, a ginger powder compress, and a mustard flour compress) in 30 healthy subjects were analyzed. For all subjects, 48-h long-term electrocardiograms were recorded, and afterward, epochs of 5 min length extracted and analyzed by different linear and nonlinear HRV indices. Results: A moist chest compress did not result in any significant short- and long-term stimulation of the autonomic regulation, except for a short-term significant decrease in heart rate (meanNN, p < 0.05). Warm and moist chest compresses with ginger flour led to significantly increased HRV (sdNN, p < 0.05; symbolic dynamics2, p < 0.05) and its complexity (renyi4 entropy, p < 0.05) and a significant decrease in heart rate (meanNN, p < 0.00036), and thus to a short-term relaxation effect. In contrast, warm and moist chest compresses with mustard flour led to significantly decreased HRV and their complexity (time-, frequency-, and nonlinear dynamics domain, p < 0.00036), which can be interpreted as a stress reaction of the autonomous nervous system. Conclusions: The application of chest compresses led to short-term relaxation effects (ginger) as well as short-term stress effects (mustard) but not to any significant longer-term effect on HRV in healthy subjects.

Detection of Liver Dysfunction Using a Wearable Electronic Nose System Based on Semiconductor Metal Oxide Sensors.

The purpose of this exploratory study was to determine whether liver dysfunction can be generally classified using a wearable electronic nose based on semiconductor metal oxide (MOx) gas sensors, and whether the extent of this dysfunction can be quantified. MOx gas sensors are attractive because of their simplicity, high sensitivity, low cost, and stability. A total of 30 participants were enrolled, 10 of them being healthy controls, 10 with compensated cirrhosis, and 10 with decompensated cirrhosis. We used three sensor modules with a total of nine different MOx layers to detect reducible, easily oxidizable, and highly oxidizable gases. The complex data analysis in the time and non-linear dynamics domains is based on the extraction of 10 features from the sensor time series of the extracted breathing gas measurement cycles. The sensitivity, specificity, and accuracy for distinguishing compensated and decompensated cirrhosis patients from healthy controls was 1.00. Patients with compensated and decompensated cirrhosis could be separated with a sensitivity of 0.90 (correctly classified decompensated cirrhosis), a specificity of 1.00 (correctly classified compensated cirrhosis), and an accuracy of 0.95. Our wearable, non-invasive system provides a promising tool to detect liver dysfunctions on a functional basis. Therefore, it could provide valuable support in preoperative examinations or for initial diagnosis by the general practitioner, as it provides non-invasive, rapid, and cost-effective analysis results.

[Laboratory study on bacteriological aspects of beverages and thickeners for dysphagia patients : Growth survey of Escherichia coli on thickeners and beverages]. / Laborstudie zu bakteriologischen Aspekten von Getränken und Andickungsmitteln für Dysphagiepatienten : Wachstumserhebung von Escherichia coli auf Andickungsmitteln und Getränken.

BACKGROUND: Currently, there is little evidence-based guidance on bacteriological aspects of thickeners or beverages for dysphagia patients in Germany that can be recommended to prevent aspiration pneumonia. Therefore, the aim of this study was to evaluate the lowest cell amount of E. coli on M9 agar media with beverages and thickeners. METHODOLOGY: In the laboratory experiment 1 · 107 cells of E. coli were plated on a defined minimal medium (M9 agar plates) with different carbon sources and incubated at 37 °C for 2 days. The increase in cell number was determined using a photometer. Carbon sources were water, beer, orange juice, thickened beer, maltodextrin-xanthan gum-based thickeners, corn starch-based thickeners and potato starch-based thickeners. RESULTS: The lowest E. coli cell amount was measured on water compared to beer, orange juice and all thickeners. A higher E. coli cell count was measured on maltodextrin-based thickeners than on potato starch-based and corn starch-based thickeners. DISCUSSION: In the present laboratory experiment, no individual risk factors for the development of aspiration pneumonia in humans were considered; however, initial bacteriological evidence for dysphagia patients could be collected. Due to the high growth of E. coli on maltodextrin, yeast, fructose and glucose, these ingredients should be used with caution by dysphagia patients. Further research on thickeners and beverages is needed to make a comprehensive recommendation for action in this aspect.

Classification of ischemic and dilated cardiomyopathy patients based on the analysis of the pulse transit time.

Cardiomyopathies diseases affects a great number of the elderly population. An adequate identification of the etiology of a cardiomyopathy patient is still a challenge. The aim of this study was to classify patients by their etiology in function of indexes extracted from the characterization of the pulse transit time (PTT). This time series represents the time taken by the pulse pressure to propagate through the length of the arterial tree and corresponding to the time between R peak of ECG and the mid-point of the diastolic to systolic slope in the blood pressure signal. For each patient, the PTT time series was extracted. Thirty cardiomyopathy patients (CMP) classified as ischemic (ICM - 15 patients) and dilated (DCM - 15 patients) were analyzed. Forty-three healthy subjects (CON) were used as a reference. The PTT time series was characterized through statistical descriptive indices and the joint symbolic dynamics method. The best indices were used to build support vector machine models. The optimal model to classify ICM versus DCM patients achieved 89.6% accuracy, 78.5% sensitivity, and 100% specificity. When comparing CMP patients and CON subjects, the best model achieved 91.3% accuracy, 91.3% sensitivity, and 88.3% specificity. Our results suggests a significantly lower pulse transit time in ischemic patients.Clinical relevance- This study analyzed the suitability of the pulse transit time for the classification of ICM and DCM patients.

Effects of yoga and mindfulness practices on the autonomous nervous system in primary school children: A non-randomised controlled study.

OBJECTIVES: The present study examined the effects of a yoga and mindfulness-based programme on the autonomic nervous system of primary school children by using heart rate variability parameters. DESIGN: A two-arm non-randomised controlled trial compared an integrated yoga and mindfulness-based programme (16 weeks) to conventional primary school lessons. SETTING: Primary school classrooms and conference rooms. INTERVENTIONS: Participants were allocated to a 16-week integrated yoga-based programme or conventional school lessons. A subgroup was randomised to receive 24h electrocardiogram-recordings. MAIN OUTCOME MEASURES: Heart rate variability indices were measured, both linear (time and frequency domain) and non-linear (symbolic dynamics, compression entropy), calculated from 30-minute extracts of Holter-electrocardiogram-recordings. Assessments were conducted at baseline and at the end of intervention. RESULTS: 40 participants (42.5% female) were included into the analysis of HRV. No significant changes in heart rate variability parameters were observed between the groups after 16 weeks. In the intervention group, a trend towards increased parasympathetic activity could be seen over time, although not significantly enhanced compared to the control group. CONCLUSION: Results obtained here do not clearly show that children in German primary school settings benefit from an integrated yoga-based intervention. However, exploratory post-hoc analyses point interestingly to an increased nocturnal parasympathetic activity in the intervention group. Further studies are required with high-quality study designs, larger sample sizes and longer-term follow-ups.

Feasibility of Multicomponent Training for People with Moderate to Severe Dementia Living in a Long-Term Care Home: A Social Ethical Approach.

Multicomponent training is recommended for people with dementia living in long-term care homes. Nevertheless, evidence is limited and people with severe dementia are often excluded from trials. Hence, the aim of this study was to investigate (1) the feasibility and (2) the requirements regarding multicomponent training for people with moderate to severe dementia. The study was conducted as an uncontrolled single arm pilot study with a mixed methods approach. Fifteen nursing home residents with a mean age of 82 years (range: 75-90 years; female: 64%) with moderate to severe dementia received 16 weeks of multicomponent training. Feasibility and requirements of the training were assessed by a standardized observation protocol. Eleven participants regularly attended the intervention. The highest active participation was observed during gait exercises (64%), the lowest during strength exercises (33%). It was supportive if exercises were task-specific or related to everyday life. This study confirms that multicomponent training for the target group is (1) feasible and well accepted, and (2) to enhance active participation, individual instructions and the implementation of exercises related to everyday life is required. The effectiveness of the adapted training should be tested in future randomized controlled trials.

Cardiorespiratory and Vascular Variability Analysis to Classify Patients with Ischemic and Dilated Cardiomyopathy.

Heart diseases are the leading cause of death in developed countries. Ascertaining the etiology of cardiomyopathies is still a challenge. The objective of this study was to classify cardiomyopathy patients through cardio, respiratory and vascular variability analysis, considering the vascular activity as the input and output of the baroreflex response. Forty-one cardiomyopathy patients (CMP) classified as ischemic (ICM, 24 patients) and dilated (DCM, 17 patients) were analyzed. Thirty-nine elderly control subjects (CON) were used as reference. From the electrocardiographic, respiratory flow, and blood pressure signals, following temporal series were extracted: beat-to-beat intervals (BBI), total respiratory cycle time series (TT), and end- systolic (SBP) and diastolic (DBP) blood pressure amplitudes, respectively. Three-dimensional representation of the cardiorespiratory and vascular activities was characterized geometrically, by fitting a polygon that contains 95% of data, and by statistical descriptive indices. The best classifiers were used to build support vector machine models. The optimal model to classify ICM versus DCM patients achieved 92.7% accuracy, 94.1% sensitivity, and 91.7% specificity. When comparing CMP patients and CON subjects, the best model achieved 86.2% accuracy, 82.9% sensitivity, and 89.7% specificity. These results suggest a limited ability of cardiac and respiratory systems response to regulate the vascular variability in these patients.

The Cardiorespiratory Network in Healthy First-Degree Relatives of Schizophrenic Patients.

Impaired heart rate- and respiratory regulatory processes as a sign of an autonomic dysfunction seems to be obviously present in patients suffering from schizophrenia. Since the linear and non-linear couplings within the cardiorespiratory system with respiration as an important homeostatic control mechanism are only partially investigated so far for those subjects, we aimed to characterize instantaneous cardiorespiratory couplings by quantifying the casual interaction between heart rate (HR) and respiration (RESP). Therefore, we investigated causal linear and non-linear cardiorespiratory couplings of 23 patients suffering from schizophrenia (SZO), 20 healthy first-degree relatives (REL) and 23 healthy subjects, who were age-gender matched (CON). From all participants' heart rate (HR) and respirations (respiratory frequency, RESP) were investigated for 30 min under resting conditions. The results revealed highly significant increased HR, reduced HR variability, increased respiration rates and impaired cardiorespiratory couplings in SZO in comparison to CON. SZO were revealed bidirectional couplings, with respiration as the driver (RESP → HR), and with weaker linear and non-linear coupling strengths when RESP influencing HR (RESP → HR) and with stronger linear and non-linear coupling strengths when HR influencing RESP (HR → RESP). For REL we found only significant increased HR and only slightly reduced cardiorespiratory couplings compared to CON. These findings clearly pointing to an underlying disease-inherent genetic component of the cardiac system for SZO and REL, and those respiratory alterations are only clearly present in SZO seem to be connected to their mental emotional states.

Quantification of maternal-fetal cardiac couplings in normal and abnormal pregnancies applying high resolution joint symbolic dynamics.

Maternal psycho-physiological activities affect the fetal development and its heart rate variability. In this work, the short-term maternal-fetal cardiac couplings in normal and abnormal fetuses were investigated by using the high resolution joint symbolic dynamics method. The analysis was applied on maternal and fetal beat-to-beat intervals of 66 normal and 19 abnormal fetuses that includes different types of congenital heart defects, tachycardia, Atrioventricular block and other types of abnormalities. Results showed that the weak decrease in maternal beat-to-beat variations associated with the strong increase in fetal beat-to-beat variations was found to be significantly higher for the abnormal cases compared to normal cases despite the heterogeneity of abnormality and gestational age (abnormal: 0.032 ±0.013, normal: 0.014 ±0.007, p < 0.01). These differences could be interpreted as impairment in the autonomic nervous system in abnormal cases. The atrioventricular block cases showed a rise in the strong increase and decrease fetal beat-to-beat variations compared to the normal cases while the tachycardia cases showed a decay in these coupling patterns.

Risk Stratification in Idiopathic Dilated Cardiomyopathy Patients Using Cardiovascular Coupling Analysis.

Cardiovascular diseases are one of the most common causes of death; however, the early detection of patients at high risk of sudden cardiac death (SCD) remains an issue. The aim of this study was to analyze the cardio-vascular couplings based on heart rate variability (HRV) and blood pressure variability (BPV) analyses in order to introduce new indices for noninvasive risk stratification in idiopathic dilated cardiomyopathy patients (IDC). High-resolution electrocardiogram (ECG) and continuous noninvasive blood pressure (BP) signals were recorded in 91 IDC patients and 49 healthy subjects (CON). The patients were stratified by their SCD risk as high risk (IDCHR) when after two years the subject either died or suffered life-threatening complications, and as low risk (IDCLR) when the subject remained stable during this period. Values were extracted from ECG and BP signals, the beat-to-beat interval, and systolic and diastolic blood pressure, and analyzed using the segmented Poincaré plot analysis (SPPA), the high-resolution joint symbolic dynamics (HRJSD) and the normalized short time partial directed coherence methods. Support vector machine (SVM) models were built to classify these patients according to SCD risk. IDCHR patients presented lowered HRV and increased BPV compared to both IDCLR patients and the control subjects, suggesting a decrease in their vagal activity and a compensation of sympathetic activity. Both, the cardio -systolic and -diastolic coupling strength was stronger in high-risk patients when comparing with low-risk patients. The cardio-systolic coupling analysis revealed that the systolic influence on heart rate gets weaker as the risk increases. The SVM IDCLR vs. IDCHR model achieved 98.9% accuracy with an area under the curve (AUC) of 0.96. The IDC and the CON groups obtained 93.6% and 0.94 accuracy and AUC, respectively. To simulate a circumstance in which the original status of the subject is unknown, a cascade model was built fusing the aforementioned models, and achieved 94.4% accuracy. In conclusion, this study introduced a novel method for SCD risk stratification for IDC patients based on new indices from coupling analysis and non-linear HRV and BPV. We have uncovered some of the complex interactions within the autonomic regulation in this type of patient.

Alterations in Maternal-Fetal Heart Rate Coupling Strength and Directions in Abnormal Fetuses.

Because fetal gas exchange takes place via the maternal placenta, there has been growing interests in investigating the patterns and directions of maternal-fetal cardiac coupling to better understand the mechanisms of placental gas transfer. We recently reported the evidence of short-term maternal-fetal cardiac couplings in normal fetuses by using Normalized Short Time Partial Directed Coherence (NSTPDC) technique. Our results have shown weakening of coupling from fetal heart rate to maternal heart rate as the fetal development progresses while the influence from maternal to fetal heart rate coupling behaves oppositely as it shows increasing coupling strength that reaches its maximum at mid gestation. The aim of this study is to test if maternal-fetal coupling patterns change in various types of abnormal cases of pregnancies. We applied NSTPDC on simultaneously recorded fetal and maternal beat-by-beat heart rates collected from fetal and maternal ECG signals of 66 normal and 19 abnormal pregnancies. NSTPDC fetal-to-maternal coupling analyses revealed significant differences between the normal and abnormal cases (normal: normalized factor (NF) = -0.21 ± 0.85, fetus-to-mother coupling area (A_fBBI→ mBBI) = 0.44 ± 0.13, mother-to-fetus coupling area (A_mBBI→ fBBI) = 0.46 ± 0.12; abnormal: NF = -1.66 ± 0.77, A_fBBI→ mBBI = 0.08 ± 0.12, A_mBBI→ fBBI = 0.66 ± 0.24; p < 0.01). In conclusion, maternal-fetal cardiac coupling strength and direction and their associations with regulatory mechanisms (patterns) of developing autonomic nervous system function could be novel clinical markers of healthy prenatal development and its deviation. However, further research is required on larger samples of abnormal cases.

Cardiovascular Coupling-Based Classification of Ischemic and Dilated Cardiomyopathy Patients.

Cardiovascular diseases are one of the most common causes of death in elderly patients. The etiology of cardiomyopathies is difficult to discern clinically. The objective of this study was to classify cardiomyopathy patients using coupling analysis, through their cardiovascular behavior and the baroreflex response. A total of thirty-eight cardiomyopathy patients (CMP) classified as ischemic (ICM, 25 patients) and dilated (DCM, 13 patients) were analyzed. Thirty elderly control subjects (CON) were used as reference. Their electrocardiographic (ECG) and blood pressure (BP) signals were studied. To characterize the cardiovascular activity, the following temporal series were extracted: beat-to-beat intervals (from the ECG signal), and end- systolic and diastolic blood pressure amplitudes (from the BP signal). Non-linear characterization techniques like high resolution joint symbolic dynamics, segmented Poincaré plot analysis, normalized shorttime partial directed coherence, and dual sequence method were used to characterize these times series. The best indices were used to build support vector machine models for classification. The optimal model for ICM versus DCM patients achieved 84.2% accuracy, 76.9% sensitivity, and 88% specificity. When CMP patients and CON subjects were compared, the best model achieved 95.5% accuracy, 97.3% sensitivity, and 93.3% specificity. These results suggest a disfunction in the baroreflex mechanism in cardiomyopathies patients.