Tag Archives: #arrhythmias

Scientists Created Technology to Detect and Treat Complex Arrhythmias (Medicine)

This is a unique method to diagnose pathogenic areas in the heart in a minute

Researchers from Belgium, the Netherlands, Russia, and Italy have developed a breakthrough method for quickly, accurately, and reliably diagnosing cardiac arrhythmias. They called it Directed graph mapping (DGM). The technology principles are published in JACC: Clinical Electrophysiology.

One of the members of the research team is Alexander Panfilov, leading specialist of the laboratory of computational biology and medicine at Ural Federal University (Russia), head of the biophysics group at the University of Ghent (Belgium), professor at the Department of Cardiology at Leiden University (Netherlands). The research was led by prof. Nele Vandersickel, a former postdoctoral researcher in Panfilov’s group.

“The pioneering step in our approach is application of novel methodology to analyze local arrival time information on the electrodes,” said Alexander Panfilov. “We connect these points into a three-dimensional network and thus track the sequential path of the wave. In mathematics, such directed networks are called graphs, they are widely used, for example, in the creation of diverse algorithms for search engines and social networks, in the diagnosis of Alzheimer’s disease, multiple sclerosis, and epilepsy. We are the first group which applied the theory of graphs to the problems of describing the electrical activity of the heart, localizing the sources of cardiac arrhythmias, identifying their mechanisms, and determining potential targets for ablation.”

First, using DGM, researchers processed the results of experiments by another group of scientists. Thus, it was possible to correct the initial conclusions and precisely establish the nature of arrhythmias.

Furthermore, DGM method underwent clinical evaluation in one of the best clinics in Belgium. The study involved 51 patients with complex atrial tachycardia. At the same time, cardiologists used the latest CARTO system of the leading medical and technological company Biosense Webster (USA). This system uses electrodes visualizes a dynamic map of wave disturbance and allows to determine a specific area of the heart where arrhythmias are formed. Test results: the method coped with the task in 38 cases, professional cardiologists – in 33 cases. In other words, DGM is highly effective in almost 75% of cases.

“Our method makes it possible to diagnose arrhythmias origin areas with high accuracy and reliability in a fully automatic mode,” said Alexander Panfilov. “In just a minute, it can localize the arrhythmia, that helps to eliminate arrhythmias in the shortest possible time. Considering that in manual data interpretation can take up to a quarter of an hour, the process is 15 times faster.”

The authors of the technique are engaged in its further improvement – to better understand the nature of the formation of arrhythmias and to treat even more complex heart diseases, such as atrial fibrillation and ventricular tachycardia.


Cardiac arrhythmias are usually caused by rotating electrical waves that disrupt the normal rhythm of the heart and can cause serious complications and even sudden death.

To cure arrhythmia, it is necessary to remove the pathogenic area in the heart and thus make it impossible for the electric wave to rotate. For this, electrodes are placed in the heart, with the help of which they establish where the wave rotates, and the removal of which area will lead to the treatment of arrhythmia. Cardiologists pass a high voltage electric current through the electrodes. The current then burns the heart tissue and dampens the wave curing the problem zone. This method is the most effective in treating arrhythmias and is called ablation.

In some cases, ablation is performed on several adjacent areas of the heart to create a whole barrier in the path of the propagating vortex. Determining the sections of wave rotation from the electrode records is a difficult task. In most cases, the cardiologist must decide on the “manual” operation. The methods of automatic identification of such sources available so far have shown their ineffectiveness, especially in cases of complex arrhythmias. As a result, the interpretation of the situation depended on the qualifications of the doctors; it took additional time to determine the treatment tactics, and the ablation procedure was laborious. These factors reduced the likelihood of a positive result of operations and increased the risk of complications.

Reference: Enid Van Nieuwenhuyse, Teresa Strisciuglio, Giuseppe Lorenzo, Milad El Haddad, Jan Goedgebeur, Nico Van Cleemput, Christophe Ley, Alexander V. Panfilov, Jan de Pooter, Yves Vandekerckhove, Rene Tavernier, Mattias Duytschaever, Sebastien Knecht, Nele Vandersickel, Evaluation of Directed Graph-Mapping in Complex Atrial Tachycardias, JACC: Clinical Electrophysiology, 2021, , ISSN 2405-500X, https://doi.org/10.1016/j.jacep.2020.12.013. (https://www.sciencedirect.com/science/article/pii/S2405500X20313189)

Provided by Ural Federal University

Fish Oil Does Not Prevent Arrhythmias (Food)

Researchers found that fish oil does not reduce the risk of developing atrial fibrillation (AF) , the most common disturbance of heart rhythm. Similarly, vitamin D supplements have no protective effect against arrhythmias. The findings were published in JAMA.

In this ancillary primary prevention AF trial that was embedded within a 2 × 2 factorial randomized clinical trial and included 25 119 participants without AF at study entry, there was no significant difference in AF incidence with marine omega-3 fatty acids vs placebo (hazard ratio, 1.09) or with vitamin D3 supplementation vs placebo (hazard ratio, 1.09) over a median 5.3 years of treatment and follow-up.

These findings do not support the use of marine omega-3 fatty acids or vitamin D3 in adults to prevent AF.

Featured image credit: gettyimages


Albert CM, Cook NR, Pester J, et al. Effect of marine omega-3 fatty acid and vitamin D supplementation on incident atrial fibrillation: A randomized clinical trial. JAMA. 2021;325(11):1061-1073. doi:10.1001/jama.2021.1489

Provided by Physicians Committee for Responsible Medicine

The Blood May Hold Clues to Some of COVID-19’s Most Mysterious Symptoms (Medicine)

The most severe cases of COVID-19 begin with leaky blood vessels. Breaches in the vascular system cause inflammation and coagulation, as fluid floods the lungs. Meanwhile, a host of seemingly unrelated symptoms set in. Blood pressure drops, arrhythmias test the heart, and the central nervous system takes a beating.

Erin Norris and Pradeep Singh discuss their research in the laboratory of Sidney Strickland. © Rockefeller University

Some studies suggest that such disparate symptoms may have a single culprit—a tiny molecule known as bradykinin—and scientists now suspect that SARS-CoV-2 is capable of toppling the delicate system that keeps this signaling substance in check. The result is a runaway bradykinin storm, the hallmarks of which just happen to be inflammation, blood coagulation, and heart, lung, and brain complications.

Rockefeller’s Sidney Strickland knows a thing or two about bradykinin, having studied it at length in the context of neurodegenerative diseases, inflammation, and blood coagulation. His lab was the first to demonstrate that the β-amyloid peptide, thought to cause Alzheimer’s disease by forming sticky plaques in the brain, also sets in motion a cascade of molecular events leading to the release of bradykinin, a likely cause of inflammation and coagulation in Alzheimer’s. Strickland’s pursuit of this relatively uncelebrated cascade may explain why vascular problems often crop up in neurodegenerative conditions.

So when COVID-19 began presenting not as a straightforward infection but a complex systemic disease—complete with the telltale signs of a bradykinin storm—the Strickland lab was ready.

“When we began looking into COVID-19, our first thought was that the inflammation characteristic of severe cases might be coming from the plasma contact system,” says Erin Norris, a research assistant professor in Strickland’s lab. The plasma contact system works by activating a plasma protein known as Factor XII, which triggers coagulation and, along the way, releases bradykinin to induce inflammation. “By investigating the plasma contact system, we can study inflammation and coagulation all at once,” she says.

A promising hypothesis

The first step for the Strickland lab is demonstrating that the novel coronavirus does indeed set off a bradykinin storm—a theory that matches the sundry symptoms but remains unproven.

Because research on a dangerous pathogen like SARS-CoV-2 requires extreme safety precautions, the lab is testing the idea using a faux coronavirus, developed in the lab of Paul Biensiasz, that is less cumbersome to work with than the real pathogen. By observing how the faux coronavirus interacts with plasma samples in the lab, scientists can determine whether the artificial virus does indeed set off a bradykinin storm by way of the contact system. If confirmed, the implications for clinicians managing severe COVID-19 cases could be imminent.

“There are existing medications that block the contact system and inhibit the production of bradykinin without interfering with the body’s main clotting pathways,” Norris says.

In a separate set of experiments, Strickland’s lab is also analyzing plasma samples from COVID-19 patients in various stages of the disease. They’re hoping to find a correlation between the severity of symptoms and the level of contact system activation since there is currently no way for doctors to predict which newly infected patients are at risk of developing life-threatening disease. If, for example, it turns out that the plasma contact system goes into overdrive before a patient takes a turn for the worse, clinicians could use this information to identify severe cases early on.

“We could create a test to determine the extent of contact system activation and use it to identify which patients are most likely to experience coagulopathy or inflammation,” Strickland says. “If certain patients are more likely to develop serious problems, it would be great to know this early on so approved medications could be employed.”

Although the research is still in its early stages, the plasma contact system is an increasingly appealing target in the fight against COVID-19. “Something is leading to coagulation and inflammation,” Strickland says. “The contact system is promising because it can do both.”

Provided by Rockefeller University

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.


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

Implantable Device Can Monitor And Treat Heart Disease (Medicine)

Pacemakers and other implantable cardiac devices used to monitor and treat arrhythmias and other heart problems have generally had one of two drawbacks – they are made with rigid materials that can’t move to accommodate a beating heart, or they are made from soft materials that can collect only a limited amount of information.

Cunjiang Yu, Bill D. Cook Associate Professor of Mechanical Engineering at the University of Houston, led a group of researchers that developed a cardiac patch made from fully rubbery electronics that can be placed directly on the heart to collect electrophysiological activity, temperature, heartbeat and other indicators, all at the same time. ©University of Houston

Researchers led by a mechanical engineer from the University of Houston have reported in Nature Electronics a patch made from fully rubbery electronics that can be placed directly on the heart to collect electrophysiological activity, temperature, heartbeat and other indicators, all at the same time.

Cunjiang Yu, Bill D. Cook Associate Professor of Mechanical Engineering at UH and corresponding author for the paper, said the device marks the first time bioelectronics have been developed based on fully rubbery electronic materials that are compatible with heart tissue, allowing the device to solve the limitations of previous cardiac implants, which are mainly made out of rigid electronic materials.

“For people who have heart arrhythmia or a heart attack, you need to quickly identify the problem,” Yu said. “This device can do that.” Yu is also a principle investigator with the Texas Center for Superconductivity at UH.

In addition to the ability to simultaneously collect information from multiple locations on the heart – a characteristic known as spatiotemporal mapping – the device can harvest energy from the heart beating, allowing it to perform without an external power source. That allows it to not just track data for diagnostics and monitoring but to also offer therapeutic benefits such as electrical pacing and thermal ablation, the researchers reported.

Yu is a leader in the development of fully rubbery electronics with sensing and other biological capabilities, including for use in robotic hands, skins and other devices. The epicardial bioelectronics patch builds upon that with a material with mechanical properties that mimic cardiac tissue, allowing for a closer interface and reducing the risk that the implant could damage the heart muscle.

“Unlike bioelectronics primarily based on rigid materials with mechanical structures that are stretchable on the macroscopic level, constructing bioelectronics out of materials with moduli matching those of the biological tissues suggests a promising route towards next-generational bioelectronics and biosensors that do not have a hard-soft interface for the heart and other organs,” the researchers wrote. “Our rubbery epicardial patch is capable of multiplexed ECG mapping, strain and temperature sensing, electrical pacing, thermal ablation and energy harvesting functions.”

References: Sim, K., Ershad, F., Zhang, Y. et al. An epicardial bioelectronic patch made from soft rubbery materials and capable of spatiotemporal mapping of electrophysiological activity. Nat Electron (2020). https://doi.org/10.1038/s41928-020-00493-6 link: https://www.nature.com/articles/s41928-020-00493-6

Provided by University Of Houston