For NBA players who get coronavirus, potential lingering heart issues concern doctors

Protocols for teams arriving to the NBA bubble (2:27)

Malika Andrews goes in depth on what the protocols will be for NBA teams arriving in Orlando, Florida, and when they can get out onto the practice court. (2:27)

As NBA teams get situated in the Orlando, Florida, bubble, one question that has persisted since the start of the coronavirus pandemic is not only what happens if a player tests positive for the virus but also what lingering effects might follow.

"There are unknown effects it has on lung capacity, unknown effects it has on cardiac health," said one general manager of a team entering the NBA bubble, speaking on the condition of anonymity. "What if a 24-year-old catches it in Orlando and, in 14 days, he quarantines and is fine, but then he has these everlasting heart problems? [Or he] gets winded so easily, or he becomes a little bit too susceptible to fatigue? ... These are all the unknowns."

There is a multistep process for anyone who tests positive, and it includes a two-week period -- either from the first positive test if the player remains asymptomatic or from the resolution of symptoms -- after which a physician will make a determination that isolation can end. The player will then take a cardiac screening in accordance with criteria outlined by the Centers for Disease Control and Prevention (CDC).

Each case will be handled based on its own needs, but John DiFiori, the NBA's director of sports medicine, told ESPN that the timeline for any player to return from a confirmed positive case is at least two weeks.

"Everyone needs to understand that if someone were to test positive, it's quite likely that they won't return to the court for a minimum of two weeks -- minimum," said DiFiori, who is also the chief of primary sports medicine and attending physician at New York City's Hospital for Special Surgery. "It may be even a little longer than that, depending on the individual circumstances, and then you need some time to get reconditioned.

"Anyone who's been out of training for two weeks is going to need time to recondition," DiFiori continued. "These things are important for everyone to understand. The players, the coaches, the medical staff, understand that if a player tests positive, they're going to need time to clear the infection management, they need additional time to recover, and then to begin reconditioning for their sport."

Matthew Martinez, a consulting cardiologist for the National Basketball Players Association, separately echoed that point to ESPN and said rest is key after a confirmed positive test because doctors believe that "the amount of cardiac damage can increase if you continue to exercise in the face of an active infection."

Martinez noted, "So you're somebody with a low-grade fever, and you have a little bit of symptoms. And, a week later, you're fine. Do you have cardiac involvement? Now, if you're a regular person, like me, and you're going to go do your [two- to three-mile runs] every day ... that's a different discussion than if you're a professional athlete.

"So that's the reason why we worry about it that that high level of exercise intensity can increase your risk of having an adverse event when there's cardiac damage related to a virus."

Any player who tests positive for the virus must undergo a "COVID-19 Pre-Participation Cardiac Screening" in accordance with CDC protocols before beginning team-organized activities, according to the league's health and safety protocols.

The reason the league and NBPA have focused specifically on the heart is myriad, but, according to a memo to teams on June 15, the basis for cardiac screening during the pandemic is tied to recommendations from the American College of Cardiology's Sports and Exercise Cardiology Council, along with feedback from consulting cardiologists for both teams and those who work with the NBPA and NBA.

"They reflect a current consensus approach, recognizing that the complete clinical picture of COVID-19 and potential effects on cardiac health, including myocarditis in particular, are not yet fully understood, and may be modified in the future to reflect new information," the league wrote in the memo.

The recommendations from the American College of Cardiology's Sports and Exercise Cardiology Council note that "Acute cardiac injury ... occur[s] in up to 22% of hospitalized patients with COVID-19, which is significantly higher compared with the approximately 1% prevalence in non-COVID-19 acute viral infections."

It further states that myocarditis -- an inflammation of the heart muscle -- from a myocyte invasion caused by the virus "could result in cardiac dysfunction, arrhythmias, and death."

DiFiori said that much of what the league and its partners have learned about how the virus affects the heart is derived from studies of patients who have been hospitalized with COVID-19.

"That data does show that there are probably two different ways that the virus can affect the heart," DiFiori said. "One of those is a direct effect of the virus itself on the heart muscle and the heart function, and the other is sort of an indirect response where the virus stimulates a massive inflammatory response, and that inflammatory response can affect heart function."

With respect to the coronavirus, DiFiori said, "We know that individuals who contract viral illnesses of a number of different types can develop myocarditis. It's fairly uncommon, but we also know that exercise and training with a possible underlying concern for myocarditis can be a major concern. So, we have to be very cautious with that possibility."

Are NBA players' hearts more at risk?

"We have no reason to believe that any athlete is at higher risk for a complication and cardiac complications related to the coronavirus than anyone else," DiFiori said. "There's no reason that we know that would suggest that right now."

Martinez, who is also the director of the Sports Cardiology and Hypertrophic Cardiomyopathy Center at Morristown Memorial Hospital in New Jersey, said doctors also believe preexisting conditions such as hypertension, diabetes or a prior heart attack can increase the risk of COVID complications.

"In the NBA, we worry a lot about player cardiac safety and evaluate annually for diseases that increased risk such as hypertrophic cardiomyopathy where the heart muscle is thickening because of a genetic predisposition," Martinez said. "For this disease, the NBPA and NBA continue that trend of taking player safety very seriously."

DiFiori acknowledged the questions about whether the virus can have any lingering respiratory effects -- especially for athletes.

"There have been discussions and considerations among the sports medicine community, and specialists in cardiology and pulmonology," he said. "I think the reason that we've focused right now more on the cardiac side is because of the potential serious immediate consequences in the short term of not managing that aspect very cautiously."

He added, "Myocarditis is a serious cardiac condition that you want to avoid and be very managed very carefully if it develops."

If the cardiac screening were to reveal anything unusual, the ensuing steps would be determined based on what was found, DiFiori said.

"That would be highly individualized, depending upon circumstances," he added. "You really can't summarize that in any neat little package because it would obviously involve additional diagnostic evaluation."

With respect to any long-term issues, DiFiori added, "It's very difficult, I think, to counsel anyone, whether you're an athlete or not, about potential long-term issues. The one thing that we would say is, listen to your physician and manage it appropriately."

He added, "If you don't feel well, don't try to push through this. This is not a situation where anyone, whether you're an athlete or not, should try to push through or minimize symptoms or try to ignore symptoms and try to push through to try to continue to work or continue to play a sport."

One NBA athletic training official of a team inside the bubble pointed out that if a player who tests positive shows symptoms, they almost certainly wouldn't be able to do any training or rehab work that would enable them to play immediately after two weeks or however long they might be out.

The league and NBPA have, in general, focused more on the heart in recent years, and part of those efforts are tied to the health screenings the NBPA instituted for retired players in the wake of several notable NBA retirees dying suddenly from heart-related issues.

"Basketball players have the highest incidence of sports-related sudden cardiac death (SCD) in the United States among all athlete groups," a 2016 study by NewYork-Presbyterian Hospital/Columbia University Medical Center reported. "The most common cause of [sudden cardiac death] for American athletes is hypertrophic cardiomyopathy (HCM), a condition that results in the thickening of the wall of the left ventricle, forcing the heart to work harder with every beat."

DiFiori noted that the league has helped with publishing multiple studies in recent years based on data collected as part of their routine cardiac screening, but it is still learning more about the virus.

"It's only been around now for six or seven months," he said, "and we're learning that it is very unique, and we don't have a very good model in terms of other viral illnesses that seem to be able to consistently be applied. And, so, with that in mind, we have to be very, very cautious in our approach."