ECG Readings Can Predict Worsening and Mortality in COVID and Influenza

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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

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