The researchers found that of more than 6,400 COVID-19 patients in their hospital, 0.6% newly developed heart failure. That included eight patients, mostly relatively young men, with no history of heart disease or risk factors for it.
Heart failure occurs when the heart cannot pump blood effectively enough to meet the body’s needs, causing symptoms such as shortness of breath, rapid heart rate, fluid buildup, and swelling in the legs and feet.
Doctors know that patients with COVID-19 can develop heart failure, but it is unclear how often it occurs.
"That’s the question that motivated this study," said lead researcher Dr. Anuradha Lala, director of heart failure research at the Icahn School of Medicine at Mount Sinai in New York City.
Based on the findings, he said, new heart failure appears to be rare and usually affects patients with a history of heart disease or stroke, or with risk factors for heart disorders, such as high blood pressure or diabetes. But a handful of patients developed heart failure despite having no risk factors. Exactly why is unclear.
"For now, the mechanisms remain elusive," Lala said.
There could be several scenarios at play, according to Lala. When patients have a history of heart problems or conditions such as high blood pressure, she said, COVID-19 may "push them over the edge" toward heart failure.
For some, it could be the stress of being seriously ill in the hospital. But the body’s inflammatory response to SARS-CoV-2, the virus that causes COVID-19, could also play a role.
Dr. Biykem Bozkurt is a professor of medicine at Baylor College of Medicine in Houston and a member of the Science and Quality Committee of the American College of Cardiology.
He said that in patients with established heart disease, the physiological stress of a severe case of COVID-19, including less oxygen reaching the heart, may be a factor precipitating new heart failure.
But more often, Bozkurt said, the cardiac complication can be driven by an overly aggressive immune response to SARS-CoV-2 and widespread inflammation in the body.
He said that since the beginning of the pandemic, it has become clear that COVID-19 can have several heart complications: Some patients develop heart attack symptoms, blood clots or an inflammation of the heart muscle called myocarditis.
With heart failure, some symptoms (such as shortness of breath) overlap with COVID-19. But doctors have additional ways to identify heart failure, Lala said: They include blood tests that look for elevations in a protein called BNP and imaging tests that detect certain structural or functional abnormalities in the heart.
How do these patients ultimately do after going home from the hospital?
"I think it’s a spectrum," Bozkurt said. If patients show improvement in symptoms and objective measures of heart structure and function, this bodes well.
Lala said it is unclear whether, for some patients with new heart failure, structural abnormalities in the heart might persist or whether signs and symptoms might recur.
COVID-19 is still a new disease, both Lala and Bozkurt said, so its long-term effects on the heart remain to be seen.
Bozkurt said anyone who has been hospitalized with COVID-19 and been told there is "cardiac compromise" should receive follow-up care with a cardiologist.
The latest findings, published online April 26 in the Journal of the American College of Cardiology, are based on more than 6,439 patients hospitalized with COVID-19 between February and June 2020.
In total, 37 patients recently developed heart failure, including eight with no known vulnerabilities. These latter patients were often quite ill, and five ended up in the intensive care unit.
However, they were less likely to die than heart failure patients with pre-existing cardiovascular disease: one in eight died, compared with six in 14.
Lala agreed that patients like these should see a cardiologist for follow-up care.
More generally, he said, researchers should continue studying the long-term effects of COVID-19 on the cardiovascular system.
