A dataset of clinically recorded radar vital signs with synchronised reference sensor signals

Using Radar it is possible to measure vital signs through clothing or a mattress from the distance. This allows for a very comfortable way of continuous monitoring in hospitals or home environments. The dataset presented in this article consists of 24 h of synchronised data from a radar and a reference device. The implemented continuous wave radar system is based on the Six-Port technology and operates at 24 GHz in the ISM band. The reference device simultaneously measures electrocardiogram, impedance cardiogram and non-invasive continuous blood pressure. 30 healthy subjects were measured by physicians according to a predefined protocol. The radar was focused on the chest while the subjects were lying on a tilt table wired to the reference monitoring device. In this manner five scenarios were conducted, the majority of them aimed to trigger hemodynamics and the autonomic nervous system of the subjects. Using the database, algorithms for respiratory or cardiovascular analysis can be developed and a better understanding of the characteristics of the radar-recorded vital signs can be gained.

Investigating the relationship between emotional granularity and cardiorespiratory physiological activity in daily life

Emotional granularity describes the ability to create emotional experiences that are precise and context-specific. Despite growing evidence of a link between emotional granularity and mental health, the physiological correlates of granularity have been under-investigated. This study explored the relationship between granularity and cardiorespiratory physiological activity in everyday life, with particular reference to the role of respiratory sinus arrhythmia (RSA), an estimate of vagal influence on the heart associated with positive mental and physical health outcomes. Participants completed a physiologically-triggered experience sampling protocol including ambulatory recording of electrocardiogram (ECG), impedance cardiogram (ICG), movement, and posture. At each prompt, participants generated emotion labels to describe their current experience. In an end-of-day survey, participants elaborated on each prompt by rating the intensity of their experience on a standard set of emotion adjectives. Consistent with our hypotheses, individuals with higher granularity exhibited a larger number of distinct patterns of physiological activity during seated rest, and more situationally-precise patterns of activity during emotional events: granularity was positively correlated with the number of patterns of cardiorespiratory physiological activity discovered in seated rest data, as well as with the performance of classifiers trained on event-related changes in physiological activity. Granularity was also positively associated with RSA during seated rest periods, although this relationship did not reach conventional levels of significance in our sample. These findings are consistent with constructionist accounts of emotion that propose concepts as a key mechanism underlying individual differences in emotional experience, physiological regulation, and physical health.

Electrode positioning to investigate the changes of the thoracic bioimpedance caused by aortic dissection – a simulation study

Impedance cardiography (ICG) is a non-invasive method to evaluate several cardiodynamic parameters by measuring the cardiac-synchronous changes in the dynamic transthoracic electrical impedance. ICG allows us to identify and quantify conductivity changes inside the thorax by measuring the impedance on the thorax during a cardiac cycle. Pathologic changes in the aorta, like aortic dissection, will alter the aortic shape as well as the blood flow and consequently, the impedance cardiogram. This fact distorts the evaluated cardiodynamic parameters, but it could lead to the possibility to identify aortic pathology. A 3D numerical simulation model is used to compute the impedance changes on the thorax surface in case of the type B aortic dissection. A sensitivity analysis is applied using this simulation model to investigate the suitability of different electrode configurations considering several patient-specific cases. Results show that the remarkable pathological changes in the aorta caused by aortic dissection alters the impedance cardiogram significantly.

Diagnosis of mitral insufficiency using impedance cardiography technique ICG

Impedance cardiography (ICG) is a non-invasive tool for assessing the hemodynamic parameters. It has been used for diagnosing several cardiovascular diseases, such as heart failure, cardio-myopathy, and valvular diseases. Particularly, the valvular heart disease is characterized by the damage in one of the four heart valves: the mitral, aortic, tricuspid or pulmonary valves. The mitral valve insufficiency and the aortic valve stenos are the most frequent valve diseases in the world. In this paper, we propose to diagnosis the mitral valve insufficiency using the impedance cardiography technique. The study group consisted of 40 subjects (20 control subjects and 20 patients with mitral insufficiency). A parameter “I” is calculated from the impedance cardiogram waveform and it is used to differentiate control subjects from patients with mitral insufficiency. The parameter “I” was related significantly to the abnormalities of the impedance cardiogram waveform. For patients with mitral insufficiency, “I” was higher than for the healthy subjects with a difference ratio of 89% (p<0.001). To improve the diagnosis, we determined the stroke volume, cardiac output, and other hemodynamic parameters for the two groups of subjects. Finally, we concluded that we could identify, easily, patients with mitral insufficiency based on the abnormalities of the impedance cardiogram tracings and a characteristic parameter “I”.