Researchers at Johns Hopkins Medicine have shown that a type of echocardiogram may be useful in predicting which patients with COVID-19 are most at risk of developing atrial fibrillation—an irregular heartbeat that can increase a person’s risk for heart failure and stroke, among other heart issues.

The new findings, published in the Journal of the American Society of Echocardiography, also suggest that patients with COVID-19 who go on to develop atrial fibrillation more commonly have elevated levels of heart-related proteins called troponin and NT-proBNP in blood test samples.

If further studies confirm the findings, “this could lead to new therapies to prevent strokes and heart attacks in certain COVID-19 patients who are at the highest risk,” says Allison Hays, MD, medical director of echocardiography programs at The Johns Hopkins Hospital and senior author of the published paper.

The COVID-19 pandemic has affected more than 170 million people around the world, and previous studies of complications and long-term effects of SARS-CoV-2 infection have found that patients who are hospitalized with COVID-19 have more than double the rate of arrhythmias, including atrial fibrillation and atrial flutter, a similar rapid rhythm that can lead to heart failure and stroke.

But exactly how the virus causes these heart complications, and who is most at risk of developing atrial fibrillation because of COVID-19, has been poorly understood.

In this study, Hays and her colleagues compared 80 patients with COVID-19 with 34 patients who did not have COVID-19 who were also treated at The Johns Hopkins Hospital in the intensive or intermediate care units for respiratory issues. None of the patients had a history of heart arrhythmia.

In the study, carried out between March and June 2020, the researchers analyzed echocardiograms of hospitalized patients, applying a special kind of analysis called speckle-tracking strain to determine how well the left atrium of the heart moves with each heartbeat.

The team found that, overall, patients with COVID-19 had reduced function of their left atrium, the chamber of the heart that receives oxygenated blood from the lungs. Left atrial strain—a measure of the movement of the left atrium’s walls—was significantly lower in patients with COVID-19 (28.2% compared with 32.6%, p=0.026; normal >38%) and left atrial emptying fraction—a measure of how much blood the atrium empties with each contraction—was also lower in the patients with COVID-19 (55.7% compared with 64.1%, p<0.001).

Moreover, left atrial strain was even lower among the 30% of patients with COVID-19 who developed atrial fibrillation or flutter during their hospital stay compared with other patients with COVID-19 (22.3% compared to 30.4%, p<0.001). This suggests that speckle-tracking analysis—and specifically, left atrial strain measurement.

“A lot of patients already get echocardiograms while in the hospital; the addition of strain analysis requires no extra scanning of the patient,” says Erin Goerlich, M.D., a cardiology fellow at the Johns Hopkins University School of Medicine and first author of the new paper. “So, this is a safe and affordable new data point that can clue us in about who might develop atrial fibrillation.”

Echocardiograms cost, on average, about $2,000 and are generally covered by health insurance. When the researchers looked at the blood of patients with COVID-19 who developed atrial fibrillation, they saw some differences compared with other patients with COVID-19. People who developed atrial fibrillation had higher levels of troponin (0.07 versus 0.03, p=0.011) and NT-proBNP (946 versus 231, p=0.0007), two known markers of heart stress.

“This tells us that COVID-19 patients with high levels of these biomarkers should be followed more closely and may benefit from an echocardiogram,” says Goerlich.

Hays cautions that the current study didn’t test whether treating patients with COVID-19 with blood thinners could help prevent the complications that can result from atrial fibrillation, which has been suggested by some clinicians. Blood thinners are generally prescribed to atrial fibrillation patients to lower the risk of blood clots and strokes.

However, the new study suggests that treating certain people—those with especially low left atrial strain, for instance—could be one path forward. More research is needed in this area, Hays says. “We’re also actively studying how these effects on the heart might persist after SARS-CoV-2 infection,” she adds. “It’s important to know whether those measures of strain and emptying fraction improve over time.”