Tag: ECG

ECG Readings Can Predict Worsening and Mortality in COVID and Influenza

Photo by Towfiqu barbhuiya from Pexels

Specific and dynamic changes on electrocardiograms (ECGs) of hospitalised COVID patients with COVID or influenza can help predict a timeframe for worsening health and death, according to a new Mount Sinai study.

Published in the American Journal of Cardiology, the study shows that shrinking waveforms on these tests can be used to help better identify high-risk patients and provide them more aggressive monitoring and treatment.  

“Our study shows diminished waveforms on ECGs over the course of COVID illness can be an important tool for health care workers caring for these patients, allowing them to catch rapid clinical changes over their hospital stay and intervene more quickly. […] ECGs may be helpful for hospitals to use when caring for these patients before their condition gets dramatically worse,” said senior author Joshua Lampert, MD, Cardiac Electrophysiology fellow at The Mount Sinai Hospital. “This is particularly useful in overwhelmed systems, as there is no wait for blood work to return and this test can be performed by the majority of health care personnel. Additionally, the ECG can be done at the time of other bedside patient care, eliminating the potential exposure of another health care worker to COVID.”

Researchers did a retrospective analysis of ECGs on 140 hospitalised COVID patients across the Mount Sinai Health System in New York City, and compared them with 281 ECGs from patients with laboratory-confirmed influenza A or B admitted to The Mount Sinai Hospital.  
For each patient, the researchers compared three ECG time points: a baseline scan done within a year prior to COVID or influenza hospitalisation, a scan taken at hospital admission, and follow-up ECGs performed during hospitalisation.

They manually measured QRS waveform height on all electrocardiograms – changes in this electrical activity can indicate failing ventricles. The researchers analysed follow-up ECGs after hospital admission and analysed changes in the waveforms according to a set of criteria they designed  called LoQRS amplitude (LoQRS) to identify a reduced signal. LoQRS was defined by QRS amplitude of less than 5mm measured from the arms and legs or less than 10mm when measured on the chest wall as well as a relative reduction in waveform height in either location by at least 50%.

Fifty-two COVID patients in the study did not survive, and 74% of those had LoQRS. Their ECG QRS waveforms reduced approximately 5.3 days into their hospital admission and they died approximately two days after the first abnormal ECG was observed.

Out of the 281 influenza patients studied, LoQRS was identified in 11 percent of them. Seventeen influenza patients died, and 39% had LoQRS present. Influenza patients met LoQRS criteria a median of 55 days into their hospital admission, and the median time to death was six days from when LoQRS was identified. Overall, these results show influenza patients followed a less virulent course of illness when compared to COVID patients.

“When it comes to caring for COVID patients, our findings suggest it may be beneficial not only for health care providers to check an EKG when the patient first arrives at the hospital, but also follow-up ECGs during their hospital stay to assess for LoQRS, particularly if the patient has not made profound clinical progress. If LoQRS is present, the team may want to consider escalating medical therapy or transferring the patient to a highly monitored setting such as an intensive care unit (ICU) in anticipation of declining health,” added Dr Lampert.

Source: The Mount Sinai Hospital / Mount Sinai School of Medicine

Screening for AF in the Elderly Using Thumb ECGs Reduces Stroke Risk

Screening for atrial fibrillation in 75- and 76-year-olds using thumb ECGS could reduce the risk of stroke, severe bleeding and death, according to a large-scale Swedish study.

Atrial fibrillation (AF) is associated with a five-fold increased risk of stroke, and the symptoms are often deleterious since large blood clots can form in the heart, breaking free and posing a stroke risk. Still, countries do not screen the general population for atrial fibrillation, but rather treat those patients who are discovered during routine care. This study by the Karolinska Institutet in Sweden and published in The Lancet, investigated the effectiveness of screening for AF.

“There has never really been a study that examines if it would be beneficial to screen for atrial fibrillation, which is why we wanted to investigate it,” said Emma Svennberg, cardiologist at the Karolinska University Hospital, Huddinge, and researcher at the Department of Medicine, Huddinge, Karolinska Institutet.

The study included almost 28 000 participants aged 75 or 76, randomised to be invited either to screening or to a control group, who received standard care. Of those invited to screening, more than half choose to participate. They completed a health questionnaire and performed a so-called thumb ECG (electrocardiogram), which involves placing one’s thumbs on an ECG device that measures the heart’s electrical activity.

Those without atrial fibrillation were asked to record their heart rhythm twice daily for two weeks using the ECG device which they took home. If the device registered irregular heart rhythms, the participants were referred to a cardiologist for a standardised work-up and, if there were no contra-indications, initiation of oral anticoagulant therapy.

The study’s 28 000 participants were then followed for at least five years. More detections of atrial fibrillation were recorded in the screening group, which also had a slightly lower incidence of death, stroke and severe bleeding than the control group.

“In total, 31.9 percent of those in the screening group experienced a negative event compared to 33 percent in the control group,” said Johan Engdahl, adjunct lecturer at the Department of Clinical Sciences, Danderyds Hospital, at Karolinska Institutet. “Now, that may sound like a small difference, but you must bear in mind that only about half of those invited to screening participated and it’s possible we would have seen a more pronounced difference had more people turned up for screening. Those who participated in the screening had significantly fewer negative events.”

Based on the findings, the researchers estimated that at least 2300 cases of stroke or death could be avoided per year in Sweden if a national screening of atrial fibrillation in the elderly was introduced.

Source: Karolinska Institute

New Early Warning System for Sudden Cardiac Death

Photo from Olivier Collett on Unsplash
Photo from Olivier Collett on Unsplash

Researchers at Tomsk Polytechnic University have developed a nanosensor-based system that can detect early abnormalities in the function of cardiac muscle cells, which otherwise can be recorded only with invasive procedures.

The nanosensor-based hardware and software complex can measure cardiac micropotential energies without filtering and averaging-out cardiac cycles in real time. The device allows registering early abnormalities in the function of cardiac muscle cells, which otherwise can be recorded only during open-heart surgery or by inserting an electrode in a cardiac cavity through a vein. Such changes can lead to sudden cardiac death (SCD). Nowadays, there are no alternatives to the Tomsk device for a number of key characteristics in Russia and the world. ).

The main method of detection of electrical pulses in the heart is electrocardiography (ECG). Nevertheless, ECG modern devices detect already critical changes in the function of the myocardium.

“Therefore, there is much concern about the creation of devices for early detection of these disorders, when it is still possible to restore cell function using medication and without surgical intervention. To implement this, it is required to record cardiac micropotential energies, electrical pulses emitted by separate cells. Here, there is a question of how to implement it noninvasive. Our research team have worked on this task for a long time, as a consequence, we jointly with the participation of our colleagues, doctors, have developed a hardware and software complex.

“The core principles of its operation are similar to ECG, however, we changed sensors: we made nanosensors instead of conventional sensors and managed to measure signals of nanovoltage and microvoltage layers without filtering and averaging-out in broadband. The use of nanosensors led to the necessity to apply original circuit solutions, write individual software.

“Ultimately, we gained a tremendous difference in sensitivity,” Diana Avdeeva, Head of the TPU Laboratory for Medical Engineering, a research supervisor of the project, said.

The system consists of a set of sensors, a tiny key device for recording incoming signals from sensors and data processing software. The sensors are fixed on a patient’s chest using a conducting gel, and the monitoring procedure takes about 20 minutes.

Conventional ECG machines operate on frequencies from 0,05 Hz to 150 Hz, while the device of the Tomsk scientists operates on much higher frequencies of up to 10 000 Hz.

“Silver chloride electrodes are usually used for recording ECG of high quality. Our sensors are also silver chloride electrodes, however, we used silver nanoparticles. There are up to 16 thin plates from porous ceramics in every our sensor, silver nanoparticles are placed in these pores. There are millions of particles in one sensor, where every particle is a silver chloride electrode capable to enhance an electric field of the heart. Silver and gold nanoparticles are capable to enhance an electromagnetic field: visible light by 10,000 folds and infrared radiation by 20 folds. We also refused to use filters for rejection network interference and noises, which are usually used in conventional ECG and significantly distort micropotentials,” Diana Avdeeva said.

The published study includes the monitoring data of one volunteer’s heart function, who took part in the research for four years and was monitored every 7-10 days.

“At the beginning of our research, we recorded clear violations of activity of cardiac muscle cells. His attending physician recommended surgery, he gained an inserted stent at the Cardiology Research Institute. Then, he continued to take part in the research and the device recorded the further gradual restoration of cardiac function,” the scientist noted.

“A task to create a sensitive, tiny and affordable complex was set up, in order in a long run, outpatient clinics and patients at home could use it. Moreover, the developed methods and devices can be used not only in cardiology.

“The fields of any electrophysiological research, such as electroencephalography, electromyography and so on are promising. Of course, before applying it to cardiology, we have to pass some essential stages. These are the collection of the required array of statistics, certification of the complex for medical use. All these stages require sponsorship, we are engaged in searching for partners and supporting programs,” said research team member Mikhail Yuzhakov, Engineer at the TPU Laboratory for Medical Engineering.

Source: Tomsk Polytechnic University