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At least 19 recordsLinked to original sources
PubMed2026

RR-interval-based atrial fibrillation detection and burden estimation: cross-dataset validation and calibration-aware probability analysis.

Objective.Atrial fibrillation (AF) burden has become an increasingly important endpoint in long-duration rhythm monitoring, but reliable burden estimation requires more than accurate AF detection alone. In particular, when burden is derived by aggregating predicted AF probabilities over time, probability calibration may directly affect burden validity under external dataset shift.Approach.This study developed an interpretable-interval feature model for AF detection and evaluated it using record-wise cross-validation on a development cohort and independent cross-dataset external validation on public Holter electrocardiographic databases. Window-level performance was assessed using the area under the receiver operating characteristic curve (ROC-AUC), area under the precision-recall curve (PR-AUC), Brier score, expected calibration error (ECE), and calibration intercept and calibration slope. Recording-level AF burden was estimated using both probability-based and hard-label aggregation and evaluated using mean absolute error (MAE) and agreement analyses.Main results.The model showed high discrimination in both development and external evaluation, with external ROC-AUC ofand PR-AUC of. However, external calibration deteriorated despite preserved ranking performance, with Brier score of, ECE(15) of, calibration intercept of, and calibration slope of. In the external cohort, probability-based burden estimation preserved strong association with reference burden but showed weaker raw agreement than hard-label aggregation, with MAE ofversus, consistent with systematic probability underprediction. Repeated external recalibration across record-level splits substantially improved probability quality and probability-based burden estimation. Median probability-burden MAE decreased fromwithout recalibration toafter Platt recalibration andafter isotonic recalibration, while median ECE(15) decreased fromtoand, respectively.Significance.These findings indicate that-interval-based AF detection maintained strong ranking performance in the tested external cohort, but probability calibration should be evaluated explicitly when predicted probabilities are aggregated into AF-burden estimates.

Atrial Fibrillation↗
PubMed2026

Reliability-aware hierarchical learning for Chagas disease screening from 12-lead ECGs: tackling label uncertainty and class imbalance.

Objective.Chagas disease, a neglected tropical disease (NTD) with significant cardiovascular impact, remains underdiagnosed in resource-limited regions. Electrocardiogram (ECG) screening offers a low-cost tool for detecting cardiac involvement, yet algorithm development is challenged by label noise, data scarcity, and the latent nature of infection. This study proposes a robust ECG-based screening framework that explicitly addresses these constraints.Approach.We introduce aReliability-Aware Hierarchical Learningstrategy that calibrates supervision according to data provenance, prioritizing serology-confirmed labels over noisy self-reports. To mitigate data scarcity, we compare a specialized convolutional neural network (CNN) trained from scratch with a transfer learning approach based on a Spatio-Temporal ECG foundation Model (FM). Performance is evaluated across varying data scales, and the representation structure is analyzed to interpret model behavior.Main results.On the official hidden test set of the George B. Moody PhysioNet/Computing in Cardiology Challenge 2025, our approach achieved a Challenge Score of 0.163. We observe that while the specialized CNN performs competitively in data-rich regimes, the FM exhibits superior robustness in extreme low-resource settings. Furthermore, performance reaches a plateau imposed by underlying disease physiology. Bimodal score distributions suggest that models distinguish established cardiomyopathy from indeterminate infection, which remains electrophysiologically indistinguishable from healthy controls.Significance.These findings clarify both the potential and intrinsic limits of ECG-based AI screening for NTD-associated cardiac involvement. Reliability-aware supervision and data-efficient transfer learning provide a practical framework toward scalable and clinically meaningful ECG screening systems in resource-constrained environments.

Humans↗
PubMed2025

Chrom-Sig: de-noising 1D genomic profiles by signal processing methods.

MOTIVATION: Modern genomic research is driven by next-generation sequencing experiments such as ChIP-seq, CUT&Tag, and CUT&RUN that generate coverage files for transcription factor binding, as well as ATAC-seq that yield coverage files for chromatin accessibility. Due to the inherent technical noise present in the experimental protocols, researchers need statistically rigorous and computationally efficient methods to extract true biological signal from a mixture of signal and noise. However, existing approaches are often computationally demanding or require input or spike-in controls. RESULTS: We developed Chrom-Sig, a Python package to quickly de-noise 1D genomic coverage tracks by computing the empirical null distribution without prior assumptions or experimental controls. When tested on 19 ChIP-seq, CUT&RUN, ATAC-seq, and snATAC-seq datasets, Chrom-Sig can effectively decompose the data into signal and noise components. Notably, Chrom-Sig performs de-noising and peak calling in 1-2 h using around 20 GB of memory. The de-noised signal corroborates with biologically meaningful results: CTCF CUT&RUN data retained a high percentage of peaks overlapping CTCF binding motifs, while ATAC-seq and RNA Polymerase II data were enriched in enhancers and promoters. We envision Chrom-Sig to be a versatile and general tool for current and future genomic technologies. AVAILABILITY AND IMPLEMENTATION: Chrom-Sig is publicly available on GitHub (https://github.com/minjikimlab/chromsig) and Zenodo (doi: 10.5281/zenodo.17488772) under the MIT licence.

Genomics↗
PubMedDate not supplied

[An electrophysiological analysis of brain maturation in chicken embryogenesis].

Studies have been made on the development of the spontaneous bioelectrical activity in the brain of 13-21-day chick embryos and on the reactions of the brain to sonic and photic stimulation (single and rhythmic). It was shown that the onset of the evoked responses to afferent stimulation coincides with predominance of a periodic process in the bioelectrical activity (17-18th days of embryogenesis). The presence of ordered rhythmicity in the bioelectrical activity of the brain which coincides with a possibility of its transformation and synchronization with afferent stimuli is suggested to be an important index of the development of the brain.

Acoustic Stimulation↗
PubMed2026

An automated geometric modeling framework in GATE for the design and optimization of high-sensitivity converging-beam SPECT collimators.

Objective.The trade-off between detection sensitivity and spatial resolution is a fundamental challenge in designing organ-dedicated Single-photon emission computed tomography (SPECT) collimators. While converging-hole geometries offer a solution, their optimization is often hindered by the lack of flexible computational tools capable of modeling large-scale, non-parallel hole arrays. This study aims to develop an automated geometric modeling framework to facilitate the design and evaluation of complex converging- and diverging-hole collimators within standard Monte Carlo environments.Approach.We developed a specialized modeling framework by implementing custom C++ classes and a vector-based alignment algorithm within GATE. This platform enables automated, orientation-consistent construction of large-scale converging arrays not natively supported by standard implementations. A high-sensitivity pure cone-beam collimator (CBC) was designed using this framework. The evaluation used hot-rod, disc, and Jaszczak phantoms for physical characterization, while XCAT and dedicated brain models were employed for clinical tasks, including cardiac, brain perfusion, and DaTscan SPECT simulations.Main results.The CBC achieved a nearly fourfold sensitivity increase compared to a conventional low-energy high-resolution parallel-hole collimator at a 20 cm radius of rotation, while maintaining comparable spatial resolution. Despite a 52.3% field of view reduction, the CBC yielded a 2.2-fold noise reduction (CV: 11.7% vs 25.9%) and mitigated partial volume effects via geometric magnification. XCAT and brain phantom simulations confirmed enhanced anatomical definition and contrast recovery in cardiac, perfusion, and DaTscan tasks.Significance.This work provides an efficient computational tool for rapid design space exploration of advanced collimator geometries. The results demonstrate that the proposed CBC design offers a significant sensitivity advantage, making it highly suitable for high-performance, small-volume clinical applications such as brain and cardiac molecular imaging.

Tomography, Emission-Computed, Single-Photon↗
PubMed1976

Suggested minimum performance characteristics of data acquisition instrumentation in computer-assisted ECG processing systems.

The increasing importance of electrocardiogram (ECG) interpretation by computers warrants consideration of the specific technical requirements for ECG recorders used in computer-assisted ECG interpretation systems. An almost uniform characteristic of these devices is their capability to transmit the ECG signal over common carrier lines. This paper suggests minimum performance characteristics for the different components of a teletransmitting ECG recorder to facilitate the use and evaluation of computer-assisted interpretation systems. Considered are the need for signal fidelity, features for automatic quality control, and features for patient and technician safety. The performance characteristics for the ECG amplifier are only stated where they exceed the most recent recommendations of the Committee on Electrocardiography, American Heart Association. The features of the teletransmission section are based on a widely used mode and format of transmission.

Amplifiers, Electronic↗
PubMedDate not supplied

Atrial electrogram monitoring in a cardiac care unit.

Routine monitoring of a bipolar atrial electrogram (AEG) simultaneously with the electrocardiogram is a useful and safe clinical technique for the diagnosis of complex cardiac dysrhythmias. The large-amplitude A waves of the AEG can be more reliably identified than the corresponding low-amplitude p waves of the electrocardiogram. Epicardial wires placed during cardiac surgery, catheter-mounted endocardial electrodes, and esophageal electrodes can all be used for routine AEG monitoring. A multipurpose pulmonary arterial catheter with a pair of electrodes, and esophageal electrodes can all be used for routine AEG monitoring. A multipurpose pulmonary arterial catheter with a pair of electrodes mounted on the proximal shaft can be used for combined AEG and hemodynamic monitoring. The equipment needed for AEG monitoring and recording consists of an additional bedside amplifier with 12- to 100-Hz band-pass filter, a dual-channel display scope, and a dual-channel strip chart recorder. Care must be used to keep the atrial electrodes electrically isolated for patient safety. In addition to enhancing the diagnosis and management of dysrhythmias, recording an AEG provides a signal that is suitable for automatic processing.

Arrhythmias, Cardiac↗
PubMed2021

Epigenetically regulated digital signaling defines epithelial innate immunity at the tissue level.

To prevent damage to the host or its commensal microbiota, epithelial tissues must match the intensity of the immune response to the severity of a biological threat. Toll-like receptors allow epithelial cells to identify microbe associated molecular patterns. However, the mechanisms that mitigate biological noise in single cells to ensure quantitatively appropriate responses remain unclear. Here we address this question using single cell and single molecule approaches in mammary epithelial cells and primary organoids. We find that epithelial tissues respond to bacterial microbe associated molecular patterns by activating a subset of cells in an all-or-nothing (i.e. digital) manner. The maximum fraction of responsive cells is regulated by a bimodal epigenetic switch that licenses the TLR2 promoter for transcription across multiple generations. This mechanism confers a flexible memory of inflammatory events as well as unique spatio-temporal control of epithelial tissue-level immune responses. We propose that epigenetic licensing in individual cells allows for long-term, quantitative fine-tuning of population-level responses.

Animals↗
PubMed1976

International standard (C.C.I.T.T.) for transmitting biomedical analogue and digital data on the public telephone network.

Analogue transmission of biomedical signals over the public telephone network has advantages from the economic point of view over digitalized transmission. This paper deals with the special problems encountered with the transmission of biomedical signals. Furthermore, the new international transmission standard C.C.I.T.T. recommendation V. 16 is introduced. This standard has recently been adopted by the relevant study group and has been presented to the Plenary Assembly of the C.C.I.T.T. for final approval. This standard is compatible with the existing public telephone networks. The technical specifications of this standard allow the transmission of the three-channel ECG for diagnostic purposes, e.g., remote processing and computer-assisted evaluation, as well as the transmission of the one-channel ECG with acoustic coupling, e.g., in emergency cases and for pace maker monitoring.

Analog-Digital Conversion↗
PubMed2026

Striping artifact removal in VisiumHD data through nuclear counts modeling.

MOTIVATION: 10x Genomics VisiumHD enables spatial transcriptomics at 2 µm × 2 µm resolution but exhibits slide-specific, non-periodic striping artifacts due to lane-width variability. These multiplicative row/column effects distort bin total counts and can bias downstream analyses. The state-of-the-art destriping approach is the normalization procedure used as a preprocessing step in bin2cell; it applies sequential high-quantile row- then column-wise normalization, which is asymmetric and can introduce edge effects/macro-stripes and distortions of large-scale total-count structure. RESULTS: We propose a statistical destriping approach that leverages nuclei segmentation from the co-registered H&E image. Assuming transcript abundance is constant within each nucleus, we model bin counts with a negative binomial distribution whose mean is a product of a nucleus-specific concentration and row- and column-specific stripe-factors reflecting lane-width variation. We fit all parameters in a generalized linear modeling framework with cross-validated regularization on stripe-factors and iterative dispersion estimation, and use the fitted parameters to correct the observed counts into a destriped image. On synthetic data with known ground truth, our method improves stripe-factor estimation accuracy and reduces error in corrected counts relative to bin2cell and bin2cell-derived baselines. Across four public VisiumHD slides, it consistently lowers striping intensity while substantially better preserving biological signal present in the large-scale global count structure and avoiding the artifacts introduced by other methods. AVAILABILITY AND IMPLEMENTATION: All source code and links to publicly available data used for this study are available at https://github.com/paolamalsot/destriping-GLM.

Artifacts↗
PubMed1977

[Universal measurement site for the processing-oriented recording of cardiovascular data].

A measuring place is described for the registration of standardized, evaluable by means of the computer deviations of bioelectric signals (parameters of heart and circulation, peripheral pulse curves and rheogramms). The high demands which concern the adequate establishment measuring places with regard to quality and comfort of attendance and condition corresponding technical solutions are explained. At the instance of the rheogram the mode of function is described. A short prognosis on the trend of development in the recognition of biological measuring values is given.

Cardiovascular Diseases↗
PubMedDate not supplied

Noninvasive external recording of cardiac conduction system (His bundle) activity.

Successful and adequate external recording of the cardiac conduction system from the body's surface can be accomplished in 80 to 90 percent of subjects studied. High-gain amplification, signal averaging, and triggering with a conditioned QRS signal results in good recording reproducibility. Averaging of 128 consecutive cycles is adequate, but on occasion averaging of 256 cycles may yield better results. The patients's QRS signal triggers the transfer of signals, which are digitized and stored during the preceding P-R interval. Comparison of external recordings with direct invasive recordings in animals and patients shows good correlation between the major His bundle deflections. The advantages of the system developed include its mobility, triggering the QRS with pretrigger data processing, and instantaneous display on Polaroid photograph. Future research should concentrate on further miniaturization and simplification of the instrumentation, detailed experimental comparison between direct and external recordings for identification of deflections and their origin, further study of the recording lead system, and the most appropriate method of information display.

Animals↗
PubMed1977

The role of the digital computer in pediatric cardiology.

A digital computer system is described which allows the real-time processing of all physiological signals obtained during a heart catheterization procedure and which makes all relevant results and informations available immediately during the investigation. In addition, special electronic units and programs have been developed in our institution for the automated extraction of morphological criteria from biplane angiocardiograms. Thereby right and left ventricular volume, shape and contraction pattern can be quantitated and used to characterize the performance of the heart as muscle and pump in physical terms. Recently, complete digital processing of videoangiocardiograms has been achieved in a stroboscopic mode, each videofield in real time. Application of image enhancement, subtraction, integration and restoration techniques leads to a fundamentally improved angiocardiographic image quality for a given amount of injected contrast material. Based on eight years of experience with digital computer application in pediatric cardiology, computer technologies are considered likely to become the method of choice in the future.

Angiocardiography↗
PubMedDate not supplied

Patient data acquisition.

Patient data are acquired in three ways: by direct interrogation; physiological measurements; and analysis of specimens, signals, and images. When computers are used to acquire information from the patient directly, difficulties arise from the lack of standardized patient medical history, the complexities of natural language processing, and the problems of man/machine communication (patient with computer terminal, and physician with computer-generated history). A great variety of data input devices have been used for the acquisition of the patient medical history. Most have been extensively used in multiphasic health testing programs, and this experience is freely drawn upon in this paper.

Computers↗
PubMed1978

[A method for automatically analysis of antenatal cardio-tocograms (author's transl)].

An off-line computer analysis of antenatal cardiotocograms has been developed. The fetal heart period (interbeat interval), the signals from uterine contractions and fetal movements, the maternal heart period and the continuous time are recorded on magnetic tape. A marking of single steps and of special events during this investigation is possible. For data processing the sequence of measuring values must be divided in shorter intervals (as a rule with a length of 30 seconds).--After this the mean value of FHR and of MHR is calculated for each interval. By computation of the standard deviation (S), the index of instantaneous arrhythmia (IAI), and the number of macrofluctuations of these intervals a quantification of the heart rate short-time-variability and long-time-variability can be performed.

Diagnosis, Computer-Assisted↗
PubMedDate not supplied

[Automatic analysis of electrocardiograph signals in the diagnosis of myocardial infarct].

At present the work of automatization of the processes of the ECG analysis for diagnosing myocardial infarction with the help of computer technique is going forward on an ever broader scale. For an automatic identification of the focal changes syndrome on the ECG, which in the clinical practice is considered to be tantanount to myocardial infarction, the use of a special diagnostic device (SDD) is proposed. The SDD are comparatively cheap and simple in operation. The process of diagnosing provides for utilization of medical experience, but, at the same time, eliminates shortcomings inherent in systems that reproduce the physicians' manipulations in establishing the diagnosis of myocardial infarction with the help of an electrocardiogram. The choice of the SDD was made by stimulating it with an all-purpose computer. The results of clinical trials of the SDD conducted at specialized clinics bear proof to great possibilities of the automatic electrocardiographic diagnostics.

Acute Disease↗