The clinical guidance was published online March 16 in the Journal of the American College of Cardiology.
"The best means to diagnose and treat myocarditis and long COVID following SARS-CoV-2 infection continues to evolve," said Ty Gluckman, MD, MHA, co-chair of the expert consensus decision pathway. "This document attempts to provide key recommendations for how to evaluate and manage adults with these conditions, including guidance for safe return to play for both competitive and noncompetitive athletes."
The authors of the guidance note that COVID-19 can be associated with various abnormalities in cardiac testing and a wide range of cardiovascular complications. For some patients, cardiac symptoms such as chest pain, shortness of breath, fatigue, and palpitations persist, lasting months after the initial illness, and evidence of myocardial injury has also been observed in both symptomatic and asymptomatic individuals, as well as after receipt of the COVID-19 mRNA vaccine.
"For clinicians treating these individuals, a growing number of questions exist related to evaluation and management of these conditions, as well as safe resumption of physical activity," they say. This report is intended to provide practical guidance on these issues.
The report states that myocarditis has been recognized as a rare but serious complication of SARS-CoV-2 infection as well as COVID-19 mRNA vaccination.
It defines myocarditis as: 1) cardiac symptoms such as chest pain, dyspnea, palpitations, or syncope; 2) elevated cardiac troponin; and 3) abnormal electrocardiographic, echocardiographic, cardiac MRI, and/or histopathologic findings on biopsy.
The document makes the following recommendations in regard to COVID-related myocarditis:
When there is increased suspicion for cardiac involvement with COVID-19, initial testing should consist of an ECG, measurement of cardiac troponin, and an echocardiogram. Cardiology consultation is recommended for those with a rising cardiac troponin and/or echocardiographic abnormalities. Cardiac MRI is recommended in hemodynamically stable patients with suspected myocarditis.
Hospitalization is recommended for patients with definite myocarditis, ideally at an advanced heart failure center. Patients with fulminant myocarditis should be managed at centers with an expertise in advanced heart failure, mechanical circulatory support, and other advanced therapies.
Patients with myocarditis and COVID-19 pneumonia (with an ongoing need for supplemental oxygen) should be treated with corticosteroids. For patients with suspected pericardial involvement, treatment with NSAIDs, colchicine, and/or prednisone is reasonable. Intravenous corticosteroids may be considered in those with suspected or confirmed COVID-19 myocarditis with hemodynamic compromise or MIS-A (multisystem inflammatory syndrome in adults). Empiric use of corticosteroids may also be considered in those with biopsy evidence of severe myocardial infiltrates or fulminant myocarditis, balanced against infection risk.
As appropriate, guideline-directed medical therapy for heart failure should be initiated and continued after discharge.
The document notes that myocarditis following COVID-19 mRNA vaccination is rare, with highest rates seen in young males after the second vaccine dose. As of May 22, 2021, the US Vaccine Adverse Event Reporting System noted rates of 40.6 cases per million after the second vaccine dose among male individuals aged 12-29 years and 2.4 cases per million among male individuals aged 30 and older. Corresponding rates in female individuals were 4.2 and 1 cases per million, respectively.
But the report says that COVID-19 vaccination is associated with "a very favorable benefit-to risk ratio" for all age and sex groups evaluated thus far.
In general, vaccine-associated myocarditis should be diagnosed, categorized, and treated in a manner analogous to myocarditis following SARS-CoV-2 infection, the guidance advises.
The document refers to long COVID as post-acute sequelae of SARS-CoV-2 infection (PASC), and reports that this condition is experienced by up to 10%–30% of infected individuals. It is defined by a constellation of new, returning, or persistent health problems experienced by individuals 4 or more weeks after COVID-19 infection.
Although individuals with this condition may experience wide-ranging symptoms, the symptoms that draw increased attention to the cardiovascular system include tachycardia, exercise intolerance, chest pain, and shortness of breath.
Nicole Bhave, MD, co-chair of the expert consensus decision pathway, says: "There appears to be a 'downward spiral' for long COVID patients. Fatigue and decreased exercise capacity lead to diminished activity and bedrest, in turn leading to worsening symptoms and decreased quality of life." She adds that "the writing committee recommends a basic cardiopulmonary evaluation performed up front to determine if further specialty care and formalized medical therapy is needed for these patients."
The authors propose two terms to better understand potential etiologies for those with cardiovascular symptoms:
PASC-CVD, or PASC-Cardiovascular Disease, refers to a broad group of cardiovascular conditions (including myocarditis) that manifest at least 4 weeks after COVID-19 infection.
PASC-CVS, or PASC-Cardiovascular Syndrome, includes a wide range of cardiovascular symptoms without objective evidence of cardiovascular disease following standard diagnostic testing.
The document makes the following recommendations for the management of PASC-CVD and PASC-CVS.
For patients with cardiovascular symptoms and suspected PASC, the authors suggest that a reasonable initial testing approach includes basic laboratory testing, including cardiac troponin, an ECG, an echocardiogram, an ambulatory rhythm monitor, chest imaging, and/or pulmonary function tests.
Cardiology consultation is recommended for patients with PASC who have abnormal cardiac test results, known cardiovascular disease with new or worsening symptoms, documented cardiac complications during SARS CoV-2 infection, and/or persistent cardiopulmonary symptoms that are not otherwise explained.
Recumbent or semi-recumbent exercise (eg, rowing, swimming, or cycling) is recommended initially for PASC-CVS patients with tachycardia, exercise/orthostatic intolerance, and/or deconditioning, with transition to upright exercise as orthostatic intolerance improves. Exercise duration should also be short (5 to 10 minutes/day) initially, with gradual increases as functional capacity improves.
Salt and fluid loading represent nonpharmacologic interventions that may provide symptomatic relief for patients with tachycardia, palpitations, and/or orthostatic hypotension.
Beta-blockers, nondihydropyridine calcium-channel blockers, ivabradine, fludrocortisone, and midodrine may be used empirically as well.
Return to Play for Athletes
The authors note that concerns about possible cardiac injury after COVID-19 fueled early apprehension regarding the safety of competitive sports for athletes recovering from the infection.
But they say that subsequent data from large registries have demonstrated an overall low prevalence of clinical myocarditis, without a rise in the rate of adverse cardiac events. Based on this, updated guidance is provided with a practical, evidence-based framework to guide resumption of athletics and intense exercise training.
They make the following recommendations:
For athletes recovering from COVID-19 with ongoing cardiopulmonary symptoms (chest pain, shortness of breath, palpitations, lightheadedness) or those requiring hospitalization with increased suspicion for cardiac involvement, further evaluation with triad testing — an ECG, measurement of cardiac troponin and an echocardiogram — should be performed.
For those with abnormal test results, further evaluation with cardiac MRI should be considered. Individuals diagnosed with clinical myocarditis should abstain from exercise for 3-6 months.
Cardiac testing is not recommended for asymptomatic individuals following COVID-19 infection. Individuals should abstain from training for three days to ensure that symptoms do not develop.
For those with mild or moderate noncardiopulmonary symptoms (fever, lethargy, muscle aches), training may resume after symptom resolution.
For those with remote infection (≥ 3 months) without ongoing cardiopulmonary symptoms, a gradual increase in exercise is recommended without the need for cardiac testing.
Based on the low prevalence of myocarditis observed in competitive athletes with COVID-19, the authors note that these recommendations can be reasonably applied to high-school athletes (aged 14 and older) along with adult recreational exercise enthusiasts.
Future study is needed, however, to better understand how long cardiac abnormalities persist following COVID-19 infection and the role of exercise training in long COVID.
The authors conclude that the current guidance is intended to help clinicians understand not only when testing may be warranted, but also when it is not.
"Given that it reflects the current state of knowledge through early 2022, it is anticipated that recommendations will change over time as our understanding evolves," they say.