The condition -- which doctors call stress cardiomyopathy -- appears similar to a heart attack, with symptoms such as chest pain and breathlessness. But its cause is different: Experts believe it reflects a temporary weakness in the heart muscle owing to a surge in stress hormones.
And at two Cleveland Clinic hospitals, diagnoses of stress cardiomyopathy shot up in the early weeks of the COVID-19 pandemic.
During March and April, the new study found, stress cardiomyopathy was diagnosed in nearly 8% of patients who arrived in the emergency department with chest pain and other possible heart symptoms.
That was four to five times higher than rates seen in pre-pandemic periods, which hovered between 1.5% and 1.8%.
And while COVID-19 can lead to heart complications, none of the patients with stress cardiomyopathy tested positive for the infection, said Dr. Ankur Kalra, a cardiologist who worked on the study.
"That suggests this is not a reflection of the virus, but the stress of the pandemic," he said.
Stress cardiomyopathy is a relatively new diagnosis, and doctors are still trying to understand it fully, Kalra said. But it got its nickname because it may arise after an emotionally difficult event, like a divorce or death of a loved one.
But other stressful situations -- from a traffic accident to surgery -- can also be triggers, Kalra said.
The condition may not arise immediately after the trigger, however, said Dr. David Kass, a professor of cardiology at Johns Hopkins University School of Medicine in Baltimore.
Kass said a person could, for example, develop stress cardiomyopathy after living through an earthquake then dealing with the fear of another one.
The condition is thought to occur when the heart muscle is overwhelmed by a flood of catecholamines -- better known as stress hormones, according to Kass. That temporarily reduces the heart's pumping ability.
The condition is quite distinct from a heart attack, he explained. There are no blockages in the arteries, and while heart muscle cells may be temporarily stunned, they do not die off.
The symptoms do mimic a heart attack, said Dr. James Januzzi, a trustee with the American College of Cardiology and a cardiologist at Massachusetts General Hospital in Boston.
But as tests are done, he said, the true cause grows clearer.
For one, Januzzi explained, stress cardiomyopathy looks different from a heart attack on electrocardiogram, which measures the heart's electrical activity. And when doctors do an angiogram to peer inside the heart arteries, they'll find no blockages in a patient with stress cardiomyopathy.
The good news, Januzzi said, is that people with the condition typically recover quickly, with no long-term heart damage.
Kass said that given all the stresses of the pandemic -- from fear of the virus to job losses to social isolation -- it's not hard to imagine why stress cardiomyopathy would increase.
But he also sounded a note of caution on the findings: From the start of the pandemic, many U.S. hospitals saw a significant drop in heart attack patients -- possibly because people feared a trip to the ER and were not calling 911.
And that, Kass said, could be one reason why the percentage of stress cardiomyopathy diagnoses rose.
"The denominator has changed," he said. "So it's hard to know whether this is actually happening a lot."
Januzzi agreed that could be a factor.
What's interesting, he said, is that none of the patients tested positive for COVID-19. Cases of "COVID-associated" stress cardiomyopathy have been reported in patients with the infection, Januzzi noted, but cases associated with the pandemic itself would be new.
And it's "very plausible," he said, that these stressful times could be leading to a true increase in the condition.
For the general public, Januzzi said, it's critical to act on symptoms of chest pain and difficulty breathing: Get to the ER and let doctors diagnose it.
Kalra agreed. He also urged people to do their best to manage stress -- getting regular exercise, for example, or using meditation to quiet the mind.
The findings were published online July 9 in JAMA Network Open.