Benchmarking heart rate variability toolboxes.

BACKGROUND: Heart rate variability (HRV) metrics hold promise as potential indicators for autonomic function, prediction of adverse cardiovascular outcomes, psychophysiological status, and general wellness. Although the investigation of HRV has been prevalent for several decades, the methods used for preprocessing, windowing, and choosing appropriate parameters lack consensus among academic and clinical investigators. METHODS: A comprehensive and open-source modular program is presented for calculating HRV implemented in Matlab with evidence-based algorithms and output formats. We compare our software with another widely used HRV toolbox written in C and available through PhysioNet.org. RESULTS: Our findings show substantially similar results when using high quality electrocardiograms (ECG) free from arrhythmias. CONCLUSIONS: Our software shows equivalent performance alongside an established predecessor and includes validated tools for performing preprocessing, signal quality, and arrhythmia detection to help provide standardization and repeatability in the field, leading to fewer errors in the presence of noise or arrhythmias.

A Thin Line Between Helpful and Harmful Internet Usage: Embodied Research on Internet Experiences Among Adolescent and Young Adult Cancer Patients.

Purpose: The purpose of this study was to expand upon findings from a prior Delphi study of adolescent and young adults' (AYAs') preferences for cancer resources. Utilizing an embodied approach, this study intended to elucidate a deeper and nuanced understanding of the expressed benefits and risks of engaging in cancer-related online interactions. Methods: Using Gale et al.'s framework method for qualitative, multidisciplinary health research and Thanem and Knights's embodied research methods for the social sciences, an investigative team of embodied researchers (AYA cancer patients turned researchers) conducted semistructured in-depth interviews with AYA cancer patients (n = 10) diagnosed between ages 15 and 39 years. To generate themes, researchers identified commonalities and differences within the qualitative data, and indexed codes according to the agreed analytic framework. Furthermore, by fully engaging with personal reflexivity, bracketing, and analytic memos across data collection and analysis, the investigative team elucidated benefits and risks of embodied research. Results: Findings impart evidence on AYAs' needs for internet-based content at the time of cancer diagnosis, use of the internet to fulfill cancer-related needs, perception of gaps in online cancer resources, and advice to other AYA cancer patients accessing internet-based information and support. Content analysis of interview data on participants' descriptions of personal engagement with the internet revealed beneficial themes of empowerment and harmful themes of fear-inducing consequences. Conclusions: In our rapidly evolving context of postpandemic internet reliance, developers of online cancer content should prioritize and respond to the nuanced vulnerabilities of AYAs. Future research must include socioeconomically disadvantaged participants to better understand practical challenges and promote health equity.

Is fertility preservation a part of comprehensive cancer care in the USA? A study of NCI-designated cancer center websites.

PURPOSE: The delivery of oncofertility care remains challenging, and cancer patients increasingly utilize online health information to fill knowledge gaps in their fertility care. The purpose of this study was to evaluate the website content of NCI-designated cancer centers to assess the quantity and quality of patient-oriented information pertaining to fertility preservation (FP). METHODS: We systematically abstracted, evaluated, and compared website content for NCI-designated cancer centers (CC) and comprehensive cancer centers (CCC) pertaining to oncofertility and fertility preservation for both male and female cancer patients. Readability of each website was evaluated using the Flesch-Kincaid grade level and Flesch reading ease score. RESULTS: Overall, 72% of websites mentioned the effect of cancer or cancer therapy on fertility potential. Only 56% of websites had a page devoted solely to the effect of cancer on fertility. Information for female patients was more common than for male patients (59% vs. 50%). CCC websites were more likely to include information about the effects of cancer treatment on fertility, the option for FP and details for FP methods. The majority of websites did not address risks and benefits of FP, moral and ethical considerations, or details about the success rates or costs. The median readability score correlated with a 12th grade reading level. CONCLUSION: Patient-directed information pertaining to oncofertility and FP is inadequate on the majority of websites, and represents a gap in comprehensive cancer care and survivorship planning. Patients who rely primarily on internet-based information regarding oncofertility may not be well-informed about FP options in the critical period between cancer diagnosis and treatment. IMPLICATIONS FOR CANCER SURVIVORS: Cancer patients and survivors interested in future fertility should be referred to reproductive specialists, when possible, for a comprehensive discussion about fertility preservation prior to cancer therapy and fertility options after completing cancer therapy.

An open source benchmarked toolbox for cardiovascular waveform and interval analysis.

OBJECTIVE: This work aims to validate a set of data processing methods for variability metrics, which hold promise as potential indicators for autonomic function, prediction of adverse cardiovascular outcomes, psychophysiological status, and general wellness. Although the investigation of heart rate variability (HRV) has been prevalent for several decades, the methods used for preprocessing, windowing, and choosing appropriate parameters lacks consensus among academic and clinical investigators. Moreover, many of the important steps are omitted from publications, preventing reproducibility. APPROACH: To address this, we have compiled a comprehensive and open-source modular toolbox for calculating HRV metrics and other related variability indices, on both raw cardiovascular time series and RR intervals. The software, known as the PhysioNet Cardiovascular Signal Toolbox, is implemented in the MATLAB programming language, with standard (open) input and output formats, and requires no external libraries. The functioning of our software is compared with other widely used and referenced HRV toolboxes to identify important differences. MAIN RESULTS: Our findings demonstrate how modest differences in the approach to HRV analysis can lead to divergent results, a factor that might have contributed to the lack of repeatability of studies and clinical applicability of HRV metrics. SIGNIFICANCE: Existing HRV toolboxes do not include standardized preprocessing, signal quality indices (for noisy segment removal), and abnormal rhythm detection and are therefore likely to lead to significant errors in the presence of moderate to high noise or arrhythmias. We therefore describe the inclusion of validated tools to address these issues. We also make recommendations for default values and testing/reporting.

Design and Testing of a Transcutaneous RF Recharging System for a Fetal Micropacemaker.

We have developed a rechargeable fetal micropacemaker in order to treat severe fetal bradycardia with comorbid hydrops fetalis. The necessarily small form factor of the device, small patient population, and fetal anatomy put unique constraints on the design of the recharging system. To overcome these constraints, a custom high power field generator was built and the recharging process was controlled by utilizing pacing rate as a measure of battery state, a feature of the relaxation oscillator used to generate stimuli. The design and in vitro and in vivo verification of the recharging system is presented here, showing successful generation of recharging current in a fetal lamb model.

Heart rate-based window segmentation improves accuracy of classifying posttraumatic stress disorder using heart rate variability measures.

OBJECTIVE: Heart rate variability (HRV) characterizes changes in autonomic nervous system function and varies with posttraumatic stress disorder (PTSD). In this study we developed a classifier based on heart rate (HR) and HRV measures, and improved classifier performance using a novel HR-based window segmentation. APPROACH: Single-channel ECG data were collected from 23 subjects with current PTSD, and 25 control subjects with no history of PTSD over 24 h. RR intervals were derived from these data, cleaned, and used to calculate HR and HRV metrics. These metrics were used as features in a logistic regression classifier. Performance was assessed via repeated random sub-sampling validation. To reduce noise and activity-related effects, we calculated features from five non-overlapping ten-minute quiescent segments of RR intervals defined by lowest HR, as well as random ten-minute segments as a control. MAIN RESULTS: Using a combination of the four most predictive features derived from quiescent segments we achieved a median area under the receiver operating curve (AUC) of 0.86 on out-of-sample test set data. This was significantly higher than the AUC using 24 h of data (0.72) or random segments (0.67). SIGNIFICANCE: These results demonstrate our segmentation approach improves the classification of PTSD from HR and HRV measures, and suggest the potential for tracking PTSD illness severity via objective physiological monitoring. Future studies should prospectively evaluate if classifier output changes significantly with worsening or effective treatment of PTSD.

A percutaneously implantable fetal pacemaker.

A miniaturized, self-contained pacemaker that could be implanted with a minimally invasive technique would dramatically improve the survival rate for fetuses that develop hydrops fetalis as a result of congenital heart block. We are currently validating a device that we developed to address this bradyarrhythmia. Preclinical studies in a fetal sheep model are underway to demonstrate that the device can be implanted via a minimally invasive approach, can mechanically withstand the harsh bodily environment, can induce effective contractions of the heart muscle with an adequate safety factor, and can successfully operate for the required device lifetime of three months using the previously-developed closed loop transcutaneous recharging system.