Endocardial repolarization dispersion in BrS: A novel automatic algorithm for mapping activation recovery interval

INTRODUCTION

Repolarization dispersion in the right ventricular outflow tract (RVOT) contributes to the type-1 electrocardiographic (ECG) phenotype of Brugada syndrome (BrS), while data on the significance and feasibility of mapping repolarization dispersion in BrS patients are scarce. Moreover, the role of endocardial repolarization dispersion in BrS is poorly investigated. We aimed to assess endocardial repolarization patterns through an automated calculation of activation recovery interval (ARI) estimated on unipolar electrograms (UEGs) in spontaneous type-1 BrS patients and controls; we also investigated the relation between ARI and right ventricle activation time (RVAT), and T-wave peak-to-end interval (Tpe) in BrS patients.

METHODS

Patients underwent endocardial high-density electroanatomical mapping (HDEAM); BrS showing an overt type-1 ECG were defined as OType1, while those without (latent type-1 ECG and LType1) received ajmaline infusion. BrS patients only underwent programmed ventricular stimulation (PVS). Data were elaborated to obtain ARI corrected with the Bazett formula (ARIc), while RVAT was derived from activation maps.

RESULTS

39 BrS subjects (24 OType1 and 15 LTtype1) and 4 controls were enrolled. OType1 and post-ajmaline LType1 showed longer mean ARIc than controls (306 ± 27.3 ms and 333.3 ± 16.3 ms vs. 281.7 ± 10.3 ms, p = .05 and p < .001, respectively). Ajmaline induced a significant prolongation of ARIc compared to pre-ajmaline LTtype1 (333.3 ± 16.3 vs. 303.4 ± 20.7 ms, p < .001) and OType1 (306 ± 27.3 ms, p < .001). In patients with type-1 ECG (OTtype1 and post-ajmaline LType1) ARIc correlated with RVAT (r = .34, p = .04) and Tpec (r = .60, p < .001), especially in OType1 subjects (r = .55, p = .008 and r = .65 p < .001, respectively).

CONCLUSION

ARIc mapping demonstrates increased endocardial repolarization dispersion in RVOT in BrS. Endocardial ARIc positively correlates with RVAT and Tpec, especially in OType1.

The Fondazione Toscana Gabriele Monasterio app: a digital health system to improve wellbeing of inpatients with heart or lung disease

BACKGROUND

An app providing material for education and entertaining is a possible way to support patients and healthcare providers in achieving person-centered care.

METHODS

An app tailored on the Fondazione Toscana Gabriele Monasterio (FTGM), a research hospital treating cardiac and lung disorders, was created. A pilot evaluation project was conducted on consecutive patients hospitalized for heart or lung disorders. Patients were asked to complete an assessment questionnaire.

RESULTS

The FTGM app provides information on diagnostic and therapeutic investigations, hospital and healthcare personnel, and includes content for entertainment and learning. It was tested on 215 consecutive patients (75% men, 66% aged >60 years, and 40% with a primary or middle school degree). Sixty-nine percentage of patients used the FTGM app, including 67% of patients aged >80 years and 65% of those with an elementary education (65%). Patients gave positive feedback on the app layout. Many (76%) looked for information on doctors and nurses in the 'People' section. Sixty-five percent of responders had used at least one of the sections called 'Music' and 'Museum visits'. The app helped many patients perceive the hospital as a more liveable place (68%), and to feel less anxious (76%), and more engaged in the diagnostic and therapeutic workup (65%). Overall, the majority of responders (87%) rated the app as 'excellent' or 'good', and almost all (95%) would have recommended other patients to use the app.

CONCLUSIONS

The FTGM app is a possible tool to improve patient wellbeing during hospitalization.

Unmet needs in end-of-life care for heart failure patients

OBJECTIVE

To investigate end-of-life (EoL) care for heart failure (HF) in Tuscany (Italy) from healthcare professionals' perspective and identify areas for intervention.

METHODS

All the directors of Cardiology units (n = 29) and palliative care (PC) units (n = 14) in Tuscany were surveyed on the practices of EoL care.

RESULTS

Forty-five percent of cardiologists reported that their hospital had some EoL care services for HF patients. However, 75% did not have a multidisciplinary team providing EoL care for HF patients. Sixty-four percent stated that <25% of patients who might benefit from PC did receive it, and 18% stated that no patient received PC. For most of PC specialists, HF patients accounted for <25% of their patients. PC specialists believed that patients with cancer diseases were much more likely to receive PC than HF patients at EoL, and 36% judged that almost no HF patients were timely referred to hospice care. The majority of PC specialists reported that almost no HF patient prepared advance healthcare directives, as opposite to 57% for cancer patients, suggesting poor understanding or acceptance of their terminal condition.

CONCLUSIONS

The management of HF patients in the EoL stage in Tuscany is often suboptimal. EoL care should be implemented to ensure an adequate quality of life to these patients.

Transmural voltage gradient dispersion and heterogeneity in brugada syndrome phenotype - a novel workflow for advanced mapping using endocardial unipolar electrograms J-point elevation

Funding Acknowledgements

Type of funding sources: None.

Background

Differential action potential duration shortening across the right ventricular (RV) myocardial wall is primarily responsible for the Brugada Syndrome (BrS) phenotype [1]. To date, data on electrical substrate characterization in humans with BrS phenotype is limited and risk evaluation is still controversial.

Purpose

We hypothesized that Uni-JEl mapping could be used as a marker of transmural voltage gradient dispersion resulting. Our aim was to evaluate Uni-JEl mapping in defining arrhythmogenic substrates in patients with BrS phenotype.

Methods

12 patients were included in our analysis. 2 normal patients provided control data and 10 asymptomatic subjects with spontaneous type-1 BrS underwent 3D RV mapping (CARTO3 System, Biosense Webster). Among BrS patients we had 3 patients with arrhythmic events (aborted sudden death or appropriate ICD therapies) during follow-up (median 56, interquartile range: 46-74 months) and 7 patients without arrhythmic events. In the former group we had 1 patient with inducibility of VT/VF during EPS (EPS+) and 2 patients non-inducibles during EPS (EPS-), in the latter group we had 3 patients with EPS+ and 4 patients with EPS-. Electrophysiological data and signals were exported and OpenEP [2] was used to convert Carto proprietary data formats into Matlab format (Fig.1). Uni-JEl was calculated for each point map as the unipolar value at J point on surface electrocardiogram. Uni-JEl values were then interpolated in Paraview to create Uni-JEl maps, interpolating data points on the mesh cell (Fig.1). Finally, a region of interest (ROI) was selected and the calculation of mean Uni-JEI (MUni-JEI, as a measure of voltage gradient dispersion), interquartile range and range (intrqUni-JEI and ∆Uni-JEI, as markers of heterogeneity of dispersion) was performed. Results are shown as mean ± standard deviation for the group of BrS patients and the actual values for the two controls.

Results

BrS patients showed Muni-JEl, intrqUni-JEl and ∆Uni-JEI higher than controls (2.03 mV ± 0.31 mV vs 0,82 mV and 1,1 mV, 1.90 mV ± 0.82 mV vs 1,04 mV and 1,18 mV 6.26 mV ± 1.98 mV vs 3,54 mV and 4,01 mV, respectively). BrS patients with arrhythmic events during the follow-up showed higher intrqUni-JEl and the ∆Uni-JEI respect to BrS with EPS+ and without arrhythmic events during follow-up (2.31 mV ± 0.44 mV vs 0.78 mV ± 0.11 mV and 6.69 mV ± 2.27 mV vs 3.98 mV ± 0.31 mV). Figure 2 shows some examples of calculated Uni-JEl maps for each group under study.

Conclusions

In this work we introduced a novel workflow for the electrical substrate characterization of subjects with BrS phenotype. The results from our preliminary analysis indicate that a higher transmural voltage gradient dispersion and heterogeneity can be found in type-1 BrS with respect to normal subjects. Voltage gradient dispersion heterogeneity could be used to better recognize high risk BrS patients regardless of VT/VF inducibility during EPS.

Mapping dependencies of BOLD signal change to end-tidal CO2: linear and nonlinear modeling, and effect of physiological noise correction

BACKGROUND

Disentangling physiological noise and signal of interest is a major issue when evaluating BOLD-signal changes in response to breath holding. Currently-adopted approaches for retrospective noise correction are general-purpose, and have non-negligible effects in studies on hypercapnic challenges.

NEW METHOD

We provide a novel approach to the analysis of specific and non-specific BOLD-signal changes related to end-tidal CO₂ (P_ETCO₂) in breath-hold fMRI studies. Multiple-order nonlinear predictors for P_ETCO₂ model a region-dependent nonlinear input-output relationship hypothesized in literature and possibly playing a crucial role in disentangling noise. We explore Retrospective Image-based Correction (RETROICOR) effects on the estimated BOLD response, applying our analysis both with and without RETROICOR and analyzing the linear and non-linear correlation between P_ETCO₂ and RETROICOR regressors.

RESULTS

The RETROICOR model of noise related to respiratory activity correlated with P_ETCO₂ both linearly and non-linearly. The correction affected the shape of the estimated BOLD response to hypercapnia but allowed to discard spurious activity in ventricles and white matter. Activation clusters were best detected using non-linear components in the BOLD response model.

COMPARISON WITH EXISTING METHOD

We evaluated the side-effects of standard physiological noise correction procedure, tailoring our analysis on challenging understudied brainstem and subcortical regions. Our novel approach allowed to characterize delays and non-linearities in BOLD response.

CONCLUSIONS

RETROICOR successfully avoided false positives, still broadly affecting the estimated non-linear BOLD responses. Non-linearities in the model better explained CO₂-related BOLD signal fluctuations. The necessity to modify the standard procedure for physiological-noise correction in breath-hold studies was addressed, stating its crucial importance.

Breath-hold task induces temporal heterogeneity in electroencephalographic regional field power in healthy subjects

We demonstrated that changes in CO₂ values cause oscillations in the cortical activity in δ-and α-bands. The analysis of the regional field power (RFP) showed evidence that different cortical areas respond with different time delays to CO₂ challenges. An opposite behavior was found for the end-tidal O₂. We suppose that the different cortical time delays likely expresse specific ascending pathways to the cortex, generated by chemoreceptor nuclei in the brain stem. Although the brain stem is in charge of the automatic control of ventilation, the cortex is involved in the voluntary control of breathing but also receives inputs from the brain stem, which influences the perception of breathing, the arousal state and sleep architecture in conditions of hypoxia/hypercapnia. We evaluated in 11 healthy subjects the effects of breath hold (BH; 30 s of apneas and 30 s of normal breathing) and BH-related CO₂/O₂ changes on electroencephalogram (EEG) global field power (GFP) and RFP in nine different areas (3 rostrocaudal sections: anterior, central, and posterior; and 3 sagittal sections: left, middle, and right) in the δ- and α-bands by cross correlation analysis. No significant differences were observed in GFP or RFP when comparing free breathing (FB) with the BH task. Within the BH task, the shift from apnea to normal ventilation was accompanied by an increase in the δ-power and a decrease in the α-power. The end-tidal pressure of CO₂ ([Formula: see text]) was positively correlated with the δ-band and negatively with the α- band with a positive time shift, whereas an opposite behavior was found for the end-tidal pressure of O₂ ([Formula: see text]). Notably, the time shift between [Formula: see text] / [Formula: see text] signals and cortical activity at RFP was heterogenous and seemed to follow a hierarchical activation, with the δ-band responding earlier than the α-band. Overall, these findings suggest that the effect of BH on the cortex may follow specific ascending pathways from the brain stem and be related to chemoreflex stimulation.NEW & NOTEWORTHY We demonstrated that the end tidal CO₂ oscillation causes oscillations of delta and alpha bands. The analysis of the regional field power showed that different cortical areas respond with different time delays to CO₂ challenges. An opposite behavior was found for the end-tidal O₂. We can suppose that the different cortical time delay response likely expresses specific ascending pathways to the cortex generated by chemoreceptor nuclei in the brainstem.

Numerical Analysis of Electromagnetic Field Exposure from 5G Mobile Communications at 28 GHZ in Adults and Children Users for Real-World Exposure Scenarios

The recent development of millimeter-wave (mmW) technologies, such as the fifth-generation (5G) network, comes with concerns related to user exposure. A quite large number of dosimetry studies above 6 GHz have been conducted, with the main purpose being to establish the correlation between different dosimetric parameters and the skin surface temperature elevation. However, the dosimetric studies from 28 GHz user equipment using different voxel models have not been comprehensively discussed yet. In this study, we used the finite-difference time-domain (FDTD) method for the estimation of the absorption of radiofrequency (RF) energy from a microstrip patch antenna array (28 GHz) in different human models. Specifically, we analyzed different exposure conditions simulating three real common scenarios (a phone call scenario, message writing scenario, and browsing scenario) regarding the use of smartphones/tablets by four different individuals (adult male and female, child male and female). From the results of Absorbed Power Density (Sab), it is possible to conclude that all the considered exposure scenarios comply with the safety limits, both for adult and children models. However, the high values of the local Specific Absorption Rate (SAR) in the superficial tissues and the slight differences in its distribution between adults and children suggest the need for further and more detailed analysis.

Research protocol for the validation of a new portable technology for real-time continuous monitoring of Early Warning Score (EWS) in hospital practice and for an early-stage multistakeholder assessment

INTRODUCTION

The real-time continuous monitoring of vital parameters in patients affected by multiple chronic conditions and/or COVID-19 can lead to several benefits to the Italian National Healthcare System (IT-NHS). The UBiquitous Integrated CARE (UBICARE) technology is a novel health digital platform at the validation stage in hospital setting. UBICARE might support the urgent need for digitalisation and early intervention, as well as minimise the face-to-face delivery of care in both hospital and community-based care settings. This research protocol aims to design an early-stage assessment of the multidimensional impact induced by UBICARE within the IT-NHS alongside technology validation in a hospital ward.

METHODS AND ANALYSIS

The targeted patients will be medium/high-risk hypertensive individuals as an illustrative first example of how UBICARE might bring benefits to susceptible patients. A mixed-method study will be applied to incorporate to the validation study a multistakeholder perspective, including perceived patient experiences and preferences, and facilitate technology adoption. First, semistructured interviews will be undertaken with a variety of stakeholders including clinicians, health managers and policy-makers to capture views on the likely technology utility, economic sustainability, impact of adoption in hospital practice and alternative adoption scenarios. Second, a monocentric, non-randomised and non-comparative clinical study, supplemented by the administration of standardised usability questionnaires to patients and health professionals, will validate the use of UBICARE in hospital practice. Finally, the results of the previous stages will be discussed in a multidisciplinary-facilitated workshop with IT-NHS relevant stakeholders to reconcile stakeholders' perspectives. Limitations include a non-random recruitment strategy in the clinical study, small sample size of the key stakeholders and potential stakeholder recruitment bias introduced by the research technique.

ETHICS AND DISSEMINATION

The Ethics Committee for Clinical Experimentation of Tuscany Region approved the protocol. Participation in this study is voluntary. Study results will be disseminated through peer-reviewed publications and academic conferences.

Ld-EEG Effective Brain Connectivity in Patients With Cheyne-Stokes Respiration

The characterization of brain cortical activity in heart-failure patients affected by Cheyne-Stokes Respiration might provide relevant information about the mechanism underlying this pathology. Central autonomic network is gaining increasing attention for its role in the regulation of breathing and cardiac functions. In this scenario, evaluating changes in cortical connectivity associated with Cheyne-Stokes Respiration may be of interest in the study of specific brain-activity related to such disease. Nonetheless, the inter subject variability, the temporal dynamics of Central-Apnea/Hyperpnea cycles and the limitations of clinical setups lead to different methodological challenges. To this aim, we present a framework for the assessment of cortico-cortical interactions from Electroencephalographic signals acquired using low-density caps and block-design paradigms, arising from endogenous triggers. The framework combines ICA-decomposition, unsupervised clustering, MVAR modelling and a permutation-bootstrap strategy for evaluating significant connectivity differences between conditions. A common network, lateralized towards the left hemisphere, was depicted across 8 patients exhibiting Cheyne-Stokes Respiration patterns during acquisitions. Significant differences in connectivity at the group level were observed based on patients' ventilatory condition. Interactions were significantly higher during hyperpnea periods with respect to central apneas and occurred mainly in the delta band. Opposite-sign differences were observed for higher frequencies (i.e. beta, low-gamma).

The Role of Haptic Stimuli on Affective Reading: a Pilot Study

The affective role of touch has opened new perspectives in human-machine interaction. This paper presents an emotion recognition algorithm to investigate the role of tactile stimuli conveyed through a wearable haptic system during affective reading. To this end, a group of 32 healthy volunteers underwent an emotional stimulation by reading affective texts, with and without the concurrent presence of pleasant haptic stimuli. Throughout the experiment, autonomic nervous system dynamics was quantified through heart rate variability (HRV) and electrodermal activity (EDA) analyses. EDA and HRV features were then used as input of a SVM-RFE learning algorithm for an automatic recognition of neutral and arousing texts. The affective recognition of the reading was performed in the presence or absence of the haptic stimulation. Results show that the affective perception induced by the neutral and arousing reading were discriminated with a significantly improved accuracy (+14.5%) when a caress-like haptic stimulus was conveyed to the user.

On the Use of Linear-Modelling-based Algorithms for Physiological Noise Correction in fMRI Studies of the Central Breathing Control

A full characterization of the physiological behavior of human central chemoreceptors through fMRI is crucial to understand the pathophysiology of central abnormal breathing patterns. In this scenario, physiological noise and activity of interest may be naturally correlated. Here, we examined the adequacy of linear-modelling-based retrospective physiological noise correction for studies of the central breathing control. We focused on the relationship between a nonlinear model of BOLD response, hypothesized to describe neuronal specific activity, and noise modelled by correction algorithms. Analyses were performed on fMRI acquisitions from healthy subjects during a breath hold task. A general linear model including static nonlinearities in the response to end-tidal CO₂ was applied to data preprocessed both with and without physiological noise correction. Relations between physiological noise and PETCO₂ were explored both with linear and nonlinear measures. Lastly, parametric maps of noise spatial distribution were extracted. Our results evidenced that correction algorithms based on linear modelling remove components that are both linearly and nonlinearly related to end-tidal CO₂, whereas uncorrected data showed spurious activations in regions outside gray matter. Thus, despite a correction step is fundamental, these algorithms are shown to be over-conservative approaches to noise correction and need to be adapted to the specific purpose.

Exploring the supra linear relationship between PetCO2 and fMRI signal change with ICA

The relationships between brain functions and the respiratory system are complex. Disentangling brain activity related to CO₂ changes from nonspecific vasoreactivity is a challenge when studying brain activity involved in the control of breathing with fMRI. In this work, we analyzed a dose dependent relationship between arterial CO₂ levels and brain response. To accomplish this goal, we developed a gas administration protocol, together with multi-subject ICA and specific nonlinear post-processing analysis. Our results highlighted a supra-linear response to CO₂ challenges in brainstem, thalamus and putamen. Results were discussed in the light of current knowledge about the central respiratory network.

Numerical evaluation of human exposure to WiMax patch antenna in tablet or laptop

The use of wireless communication devices, such as tablets or laptops, is increasing among children. Only a few studies assess specific energy absorption rate (SAR) due to exposure from wireless-enabled tablets and laptops, in particular with Worldwide Interoperability for Microwave Access (WiMax) technology. This paper reports the estimation of the interaction between an E-shaped patch antenna (3.5 GHz) and human models, by means of finite-difference time-domain (FDTD) method. Specifically, four different human models (young adult male, young adult female, pre-teenager female, male child) in different exposure conditions (antenna at different distances from the human model, in different positions, and orientations) were considered and whole-body, 10 and 1 g local SAR and magnetic field value (Bmax) were evaluated. From our results, in some worst-case scenarios involving male and female children's exposure, the maximum radiofrequency energy absorption (hot spots) is located in more sensitive organs such as eye, genitals, and breast. Bioelectromagnetics. 39:414-422, 2018. © 2018 Wiley Periodicals, Inc.

A Cross-Correlational Analysis between Electroencephalographic and End-Tidal Carbon Dioxide Signals: Methodological Issues in the Presence of Missing Data and Real Data Results

Electroencephalographic (EEG) irreducible artifacts are common and the removal of corrupted segments from the analysis may be required. The present study aims at exploring the effects of different EEG Missing Data Segment (MDS) distributions on cross-correlation analysis, involving EEG and physiological signals. The reliability of cross-correlation analysis both at single subject and at group level as a function of missing data statistics was evaluated using dedicated simulations. Moreover, a Bayesian-based approach for combining the single subject results at group level by considering each subject’s reliability was introduced. Starting from the above considerations, the cross-correlation function between EEG Global Field Power (GFP) in delta band and end-tidal CO₂ (P_ETCO₂) during rest and voluntary breath-hold was evaluated in six healthy subjects. The analysis of simulated data results at single subject level revealed a worsening of precision and accuracy in the cross-correlation analysis in the presence of MDS. At the group level, a large improvement in the results’ reliability with respect to single subject analysis was observed. The proposed Bayesian approach showed a slight improvement with respect to simple average results. Real data results were discussed in light of the simulated data tests and of the current physiological findings.

Exploratory analysis of nonlinear coupling between EEG global field power and end-tidal carbon dioxide in free breathing and breath-hold tasks

Brain activations underlying control of breathing are not completely known. Furthermore, the coupling between neural and respiratory dynamics is usually estimated through linear correlation measures, thus totally disregarding possible underlying nonlinear interactions. To overcome these limitations, in this preliminary study we propose a nonlinear coupling analysis of simultaneous recordings of electroencephalographic (EEG) and respiratory signals at rest and after variation of carbon dioxide (CO2) level. Specifically, a CO2 increase was induced by a voluntary breath hold task. EEG global field power (GFP) in different frequency bands and end-tidal CO2 (PETCO2) were estimated in both conditions. The maximum information coefficient (MIC) and MIC-ρ2 (where ρ represents the Pearson's correlation coefficient) between the two signals were calculated to identify generic associations (i.e. linear and nonlinear correlations) and nonlinear correlations, respectively. With respect to a free breathing state, our results suggest that a breath hold state is characterized by an increased coupling between respiration activity and specific EEG oscillations, mainly involving linear and nonlinear interactions in the delta band (1-4 Hz), and prevalent nonlinear interactions in the alpha band (8-13 Hz).

Correlational analysis of electroencephalographic and end-tidal carbon dioxide signals during breath-hold exercise

The central mechanism of breathing control is not totally understood. Several studies evaluated the correlation between electroencephalographic (EEG) power spectra and respiratory signals by performing resting state tasks or adopting hypercapnic/hypoxic stimuli. The observation of brain activity during voluntary breath hold tasks, might be an useful approach to highlight the areas involved in mechanism of breath regulation. Nevertheless, studies of brain activity with EEG could present some limitations due to presence of severe artifacts. When artifact rejection methods, as independent component analysis, cannot reliably clean EEG data, it is necessary to exclude noisy segments. In this study, global field power in the delta band and end-tidal CO2 were derived from EEG and CO2 signals respectively in 4 healthy subjects during a breath-hold task. The cross correlation function between the two signals was estimated taking into account the presence of missing samples. The statistical significance of the correlation coefficients at different time lags was assessed using surrogate data. Some simulations are introduced to evaluate the effect of missing data on the correlational analysis and their results are discussed. Results obtained on subjects show a significant correlation between changes in EEG power in the delta band and end-tidal CO2. Moreover, the changes in end-tidal CO2 were found to precede those of global field power. These results might help to better understand the cortical mechanisms involved in the control of breathing.

Stevens-Johnson Syndrome and cholestatic hepatitis

Stevens-Johnson Syndrome (SJS) is a rare but severe dermatological condition that typically occurs after the ingestion of medications such as nonsteroidal drugs, antibiotics, and anticonvulsants. Extracutaneous manifestations of the syndrome can occur and may involve the conjunctiva, trachea, buccal mucosa, gastrointestinal tract, and genitourinary tract. Cholestatic liver disease, which may precede the skin manifestations of SJS, has been reported to occur in SJS, but the medical literature has only 10 case reports describing this phenomenon (1-9). We report the case of a 19-year-old female with SJS and cholestatic liver disease. A discussion of the underlying pathophysiology of SJS and its treatment follows.