Tag Archives: #electrocardiogram

What Do Slight Arm Movements Reveal About Our Breathing and Health? (Medicine)

Special activity trackers can be used to fairly accurately determine the respiratory rate of people while they sleep. This is the result of a new study conducted by researchers at Martin Luther University Halle-Wittenberg (MLU) together with Charité – Universitätsmedizin Berlin and published in the journal Scientific Reports. In the future, activity trackers could be used to detect the early stages of a disease, as a person’s respiratory rate can indicate signs of an undetected medical problem.

Breathing tells a lot about a patient’s health. Several studies have shown that deviations from a normal respiratory rate, which is about 12 to 18 times a minute, can be an indication of a serious illness. Breathing less than six times a minute is a stronger indication of a life-threatening issue than an abnormal heartbeat. Conversely, very rapid breathing can be an early sign of heart problems. “Nevertheless, the relevance of respiratory rates in the early detection of medical risks has garnered little attention,” says Dr Jan Kantelhardt, a physicist at MLU. For several years now, his research group has been investigating how physical data from measuring devices can improve patient diagnostics.

To date, a reliable measurement of respiratory rates over longer periods of time is only possible in clinics that have the right equipment. However, health studies with several hundred thousand participants, for example, require simpler devices. Up to now, a standard electrocardiogram (ECG) has often been used to measure heart rates and rhythms, thus allowing conclusions to be drawn about breathing. “We were looking for a new, inexpensive way to measure respiration,” says Kantelhardt.

Together with the research group led by Professor Thomas Penzel from the Interdisciplinary Center of Sleep Medicine at the Charité, the team from Halle wanted to examine whether special activity trackers could provide a reliable alternative to ECGs. Staff members in the sleep laboratory at the Charité placed a wristband, in addition to the usual equipment, on around 400 patients. The wristbands registered movement and also took a simple ECG measurement via an electrode attached to the skin. “They are like fitness trackers but much more precise. We can use our own software to analyse the raw data,” says Kantelhardt. This enables the researchers to detect the slightest bit of movement – even if the patient’s arm turns slightly when breathing while asleep.

Acceleration recording at the wrist. The photo shows the placement of the SOMNOwatch plus device (Somnomedics GmbH, Randersacker, Germany) at the wrist with the coordinate axes (x, y, and z; yellow) according to the device’s orientation as well as the gravity acceleration vector (red) pointing vertically upwards from the center of the earth. The device measures the three components of the gravity acceleration with respect to its coordinate axes. ©Julian Luebe et al.

A comparison of the data from the sleep laboratory showed that these minimal movements allow more precise conclusions to be drawn about the respiratory rate than the ECG recorded at the same time. “If there is too much movement, breathing can no longer be measured with the armbands. But there are always periods at night where we can very reliably observe breathing,” says Kantelhardt. According to the researcher, the armbands could be used, for example, as a diagnostic tool before a patient is sent to a sleep laboratory.

The new method will initially be used to evaluate some of the data from the so-called GNC Health Study, which began in 2014. As part of the long-term nationwide study, approximately 200,000 people regularly undergo medical examinations and interviews about their living conditions and medical histories. Some of the participants also received the same activity trackers as those in the current study. The overall aim of the project is to better understand the development of common diseases such as cancer, diabetes or cardiac arrhythmia in order to improve preventative measures, early diagnosis, and treatment in Germany.

The study was supported by the German-Israeli Foundation for Scientific Research and Development (GIF) and by the Federal Ministry of Education and Research and the Helmholtz Association as part of the GNC Health Study.

References: Leube, J. et al. Reconstruction of the respiratory signal through ECG and wrist accelerometer data. Scientific Reports (2020). doi: 10.1038/s41598-020-71539-0 https://www.nature.com/articles/s41598-020-71539-0

Provided by Martin Luther Universität Halle Wittenburg

Non-invasive Electrolyte Levels’ Measuring Method Can Prevent Sudden Cardiac Death (Medicine)

Researchers from Kaunas University of Technology (KTU), Lithuania came up with the idea on how to measure fluctuating blood potassium levels non-invasively, through electrocardiogram.

Researchers from Kaunas University of Technology (KTU), Lithuania came up with the idea on how to measure fluctuating blood potassium levels non-invasively, through electrocardiogram. The researchers claim that their method may become a digital biomarker in the future for managing electrolyte levels. This would be a huge step towards preventing potentially life-threatening conditions among people who suffer from chronic kidney disease.

©KTU

Electrolytes and especially potassium, are paramount in the conduction of the heart’s cells. When electrolytes are too low or too high, the heart cannot contract normally, leading to dangerous arrhythmias and potentially sudden cardiac death.

“Electrolyte levels are kept within the healthy range by the kidneys. However, the patients with the last stage of chronic kidney disease, who have no renal function left, rely on hemodialysis to keep their electrolyte levels regulated. This means that they are prone to electrolyte imbalance in a 2-day-long hiatus between hemodialysis sessions”, explains Ana Rodrigues, researcher at KTU Biomedical Engineering Institute, one of the authors of the invention.

According to Rodrigues, with today’s aging society, it is estimated that the number of people requiring hemodialysis will markedly increase within 10 years. As people age, so do their kidneys. Research shows that up to 50 percent of seniors over the age of 75 can have kidney disease.

Abnormal electrolyte levels disturb the heart’s natural rhythm; such abnormalities can be reflected in the electrocardiogram. However, identifying electrolyte imbalance using an electrocardiogram is difficult due to confounding factors that mask these expected changes. The task becomes particularly complicated if electrolyte levels start to fluctuate beyond normal, but not reaching levels that require immediate medical attention.

The method proposed by the team of KTU researchers, tackles the problem through mathematical models that enable to quantify subtle changes that are not visible to the naked eye at the early stages of electrolyte imbalance. The method allows to spot potassium – the most arrhythmogenic electrolyte – induced changes in a certain part of the electrocardiogram.

“The initial results are promising. Our method may become a digital biomarker in the future for the management of electrolyte levels”, says Rodrigues.

Researchers in Lithuania came up with the idea which would allow measuring electrolyte balance noninvasively at home through an electrocardiogram. ©KTU

The method proposed by KTU researchers allows detecting abnormal potassium levels before the onset of life-threatening arrhythmias. Patients could then start hemodialysis sooner, decreasing the chance of hospitalization and even premature death.

Usually, in order to detect the changes in electrolyte balance, a blood sample would be drawn from a patient. However, blood samples are not routinely requested and cannot be drawn outside a clinical environment. Thus, researchers in Lithuania came up with the idea which would allow measuring electrolyte balance noninvasively at home through an electrocardiogram.

“Noninvasive monitoring of electrolyte levels is a very novel concept and is now in its infancy stages. Our paper is one of the first papers published on the topic and, to the best of our knowledge, the first to investigate potassium fluctuations in ambulatory settings between hemodialysis sessions”, says Rodrigues.

The research is the outcome of the close collaboration between KTU, Lithuanian University of Health Sciences (LSMU) and the University of Zaragoza, Spain.

At the moment, clinical studies involving 17 patients have been completed. The researchers are planning on continuing clinical trials with more patients in order to validate their findings. Their next goal is to create an algorithm that would include measuring different electrolyte levels, such as calcium.

Later on, the algorithm could be integrated into wearable wrist-worn device capable of acquiring electrocardiograms. Every once in a while, the patient would record a short electrocardiogram signal (roughly 2-min long) using their fingers, and the system would register the electrolyte levels. If electrolytes were at an alarming level, the clinic would be notified, and the patient would be instructed accordingly.

References: A. S. Rodrigues et al., “Noninvasive Monitoring of Potassium Fluctuations During the Long Interdialytic Interval,” in IEEE Access, vol. 8, pp. 188488-188502, 2020.
doi: 10.1109/ACCESS.2020.3031471 http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=9225155&isnumber=8948470

Provided by Kaunas University of Technology