Cardiac and extracardiac discharge diagnosis prediction from emergency department ECGs using deep learning

Current deep learning algorithms designed for automatic ECG analysis have exhibited notable accuracy. However, akin to traditional electrocardiography, they tend to be narrowly focused and typically address a singular diagnostic condition. In this study, we specifically demonstrate the capability of a single model to predict a diverse range of both cardiac and non-cardiac discharge diagnoses based on a sole ECG collected in the emergency department. Among the 1,076 hierarchically structured ICD codes considered, our model achieves an AUROC exceeding 0.8 in 439 of them. This underscores the models proficiency in handling a wide array of diagnostic scenarios. We emphasize the potential of utilizing this model as a screening tool, potentially integrated into a holistic clinical decision support system for efficiently triaging patients in the emergency department. This research underscores the remarkable capabilities of comprehensive ECG analysis algorithms and the extensive range of possibilities facilitated by the open MIMIC-IV-ECG dataset. Finally, our data may play a pivotal role in revolutionizing the way ECG analysis is performed, marking a significant advancement in the field.

Uncovering ECG Changes during Healthy Aging using Explainable AI

Cardiovascular diseases remain the leading global cause of mortality. This necessitates a profound understanding of heart aging processes to diagnose constraints in cardiovascular fitness. Traditionally, most of such insights have been drawn from the analysis of electrocardiogram (ECG) feature changes of individuals as they age. However, these features, while informative, may potentially obscure underlying data relationships. In this paper, we employ a deep-learning model and a tree-based model to analyze ECG data from a robust dataset of healthy individuals across varying ages in both raw signals and ECG feature format. Explainable AI techniques are then used to identify ECG features or raw signal characteristics are most discriminative for distinguishing between age groups. Our analysis with tree-based classifiers reveal age-related declines in inferred breathing rates and identifies notably high SDANN values as indicative of elderly individuals, distinguishing them from younger adults. Furthermore, the deep-learning model underscores the pivotal role of the P-wave in age predictions across all age groups, suggesting potential changes in the distribution of different P-wave types with age. These findings shed new light on age-related ECG changes, offering insights that transcend traditional feature-based approaches.

Diffusion-based Conditional ECG Generation with Structured State Space Models

Synthetic data generation is a promising solution to address privacy issues with the distribution of sensitive health data. Recently, diffusion models have set new standards for generative models for different data modalities. Also very recently, structured state space models emerged as a powerful modeling paradigm to capture long-term dependencies in time series. We put forward SSSD-ECG, as the combination of these two technologies, for the generation of synthetic 12-lead electrocardiograms conditioned on more than 70 ECG statements. Due to a lack of reliable baselines, we also propose conditional variants of two state-of-the-art unconditional generative models. We thoroughly evaluate the quality of the generated samples, by evaluating pretrained classifiers on the generated data and by evaluating the performance of a classifier trained only on synthetic data, where SSSD-ECG clearly outperforms its GAN-based competitors. We demonstrate the soundness of our approach through further experiments, including conditional class interpolation and a clinical Turing test demonstrating the high quality of the SSSD-ECG samples across a wide range of conditions.

Diffusion-based Time Series Imputation and Forecasting with Structured State Space Models

The imputation of missing values represents a significant obstacle for many real-world data analysis pipelines. Here, we focus on time series data and put forward SSSD, an imputation model that relies on two emerging technologies, (conditional) diffusion models as state-of-the-art generative models and structured state space models as internal model architecture, which are particularly suited to capture long-term dependencies in time series data. We demonstrate that SSSD matches or even exceeds state-of-the-art probabilistic imputation and forecasting performance on a broad range of data sets and different missingness scenarios, including the challenging blackout-missing scenarios, where prior approaches failed to provide meaningful results.

From Interpretable Filters to Predictions of Convolutional Neural Networks with Explainable Artificial Intelligence

Convolutional neural networks (CNN) are known for their excellent feature extraction capabilities to enable the learning of models from data, yet are used as black boxes. An interpretation of the convolutional filtres and associated features can help to establish an understanding of CNN to distinguish various classes. In this work, we focus on the explainability of a CNN model called as cnnexplain that is used for Covid-19 and non-Covid-19 classification with a focus on the interpretability of features by the convolutional filters, and how these features contribute to classification. Specifically, we have used various explainable artificial intelligence (XAI) methods, such as visualizations, SmoothGrad, Grad-CAM, and LIME to provide interpretation of convolutional filtres, and relevant features, and their role in classification. We have analyzed the explanation of these methods for Covid-19 detection using dry cough spectrograms. Explanation results obtained from the LIME, SmoothGrad, and Grad-CAM highlight important features of different spectrograms and their relevance to classification.