Why Americans may be at risk of heart problems as COVID, flu spread: Expert

As a surge of respiratory viruses, including COVID-19 and influenza, continue to spread across the United States, experts are warning it could lead to a rise in cardiovascular complications.

Weekly COVID hospitalizations are currently sitting at 32,861 for the week ending Jan. 13, lower than the week before but similar to levels seen in January 2023, according to data from the Centers for Disease Control and Prevention (CDC).

Similarly, there were 14,874 weekly flu hospitalizations, lower than the week before but comparable to levels seen in November 2023, the data shows.

Many Americans may assume that complications from respiratory illnesses are limited to sinusitis, bronchitis, pneumonia and other sicknesses that affect the upper or lower respiratory tracts.

However, Dr. Deepak Bhatt, director of Mount Sinai Fuster Heart Hospital in New York City, said there are two potential routes by which these infections can contribute to heart problems.

"The more common pathway is if somebody gets really sick, say with influenza, running a high fever or getting dehydrated, getting hospitalized because of complications of influenza," he told ABC News. "That's a setup for having heart problems."

Fever or dehydration can raise a patient's heart rate and, particularly for those who have heart disease or heart disease risk factors, this can be very dangerous. Additionally, respiratory infections can cause inflammation, which, in turn, can cause plaques in the blood to form clots -- a potential trigger of heart attacks.

"The inflammation is a result of any serious infection but, including infections like influenza and COVID, can then cause inflammation at the site of plaque buildup in a heart artery and that can help promote that plaque to rupture," Bhatt said. "Or in other words, flowing blood is exposed to the inner contents of that fat and cholesterol and when that happens, blood clots form, and if they block the artery completely, that's what can cause a heart attack."

The other pathway, which is more direct but rarer, is myocarditis, which is inflammation of the heart muscle, usually following a virus.

Myocarditis can cause arrhythmias, which are rapid or abnormal heartbeats. It can also cause the heart muscle to weaken, resulting in cardiomyopathy, which affects the heart's ability to pump blood effectively.

Additionally, in rare circumstances, myocarditis can lead to heart failure and cardiogenic shock -- another condition in which the heart can't pump enough blood to meet the body's needs -- even in otherwise healthy patients.

While these conditions are more likely to affect older adults, those with known heart disease, or those have known multiple cardiovascular risk factors, Bhatt said there may be people who don't know they're at risk.

"One challenge with heart disease is not everybody knows that they have it," he said. "That is, there are people that are walking around with heart disease, but the diagnosis hasn't been made, because they've not had any symptoms yet."

He continued, "But the stressor of a really severe illness, like influenza, can sort of then unmask what has sort of been there all along, but sitting there silently."

Bhatt recommends anyone who is not yet vaccinated against flu and COVID, and RSV for older adults, should get their shots now.

CDC data showed that uptake has been lagging As of Friday, just 21.5% of adults aged 18 and older have gotten the updated COVID vaccine and 46.7% have gotten the flu shot. Additionally, just 2.1% of adults aged 60 and older have gotten the RSV vaccine.

More importantly, if someone is sick and they have chest pain or are out of breath that is worsening, they should call their doctor or 911, regardless of whether or not they have an underlying condition or risk factors, he said.

"If somebody's having really significant discomfort in the chest and symptoms in the chest, and it's getting worse, especially rapidly, don't just assume it's because, 'Oh, I have a bad cold, or I have influenza, or I have COVID," Bhatt said. "Calling 911 is always the right thing to do."