New AHA Statement on Management of Fulminant Myocarditis

Batya Swift Yasgur MA, LSW

January 13, 2020

The American Heart Association (AHA) has released a new scientific statement on the recognition and initial management of fulminant myocarditis (FM), focusing on timely diagnosis and treatment of this uncommon but potentially fatal condition.

FM, a severe, rapidly progressing cardiac inflammation often caused by viral infection, comes on suddenly and is associated with high risk for death from cardiogenic shock, arrhythmias, and multiorgan failure.

"This is the first statement of its kind for management of fulminant myocarditis," Leslie Cooper, MD, vice chair of the Statement Writing Group, told | Medscape Cardiology.

"The primary message of our statement is for frontline providers — primary emergency room doctors and hospitalists — to recognize cardiogenic shock early and refer patients to specialists or centers that have the capability to support patients through mechanical support or transplants," he said.

The statement was published online January 6 in Circulation.

Fully Treatable

The authors define FM as "a sudden and severe inflammation of the myocardium resulting in myocyte necrosis, edema, and cardiogenic shock."

"Myocarditis is one of the causes of acute or sudden cardiac shock, with the other reasons being ischemic disease or structural problems, such as acute rupture of the mitral valve or heart attack, but these typically affect an older population," Cooper said.

"FM more often affects a younger population, with an average age of about 40, and is caused by a virus, and although FM is one of the least common causes of myocarditis, it's also one of the most important because it's so severe."

Nevertheless, he added, "it is fully treatable."

Conditions that can result in FM include lymphocytic myocarditis (which may be caused by inflammatory cardiomyopathy related to autoimmune, toxic, or infectious causes) and giant cell myocarditis.

Additionally, myocarditis can be caused by acute necrotizing eosinophilic myocarditis (NEM), typically associated with certain drugs (such as adalimumab, amoxicillin, carbamazepine, clozapine, spironolactone, and tetracycline). The authors note that some novel cancer therapies have also been implicated.

"It is important to remember that millions of people are getting these drugs and to be aware that they can cause FM," Cooper emphasized.

High Index of Suspicion

Although historically, FM was diagnosed "almost exclusively" at autopsy, today's diagnostic technologies can identify it early on, while the patient is still alive and can receive intervention, and modern-day technology has made available an array of tools to treat the condition.

Clinical signs "vary widely," and the condition may or may not present with systemic manifestations of infection or inflammatory disorders, they note.

The authors list telltale symptoms, including dyspnea followed by chest pain and arrhythmias or heart block. In addition, cardiogenic or mixed cardiogenic and distributive shock may develop rapidly.

Red flags suggesting the presence of FM include:

  • The presence of "apparent cardiovascular conditions," such as acute coronary syndrome or de novo acute heart failure, in a young patient

  • History of signs or symptoms of recent viral upper respiratory tract infection or enteroviral infection presenting with cardiovascular symptoms in young patients without typical cardiovascular risk factors

  • The presence of shock, electric instability, or rapidly evolving conduction abnormalities

  • Right-sided heart failure

  • Early recognition of circulatory compromise

They acknowledge that it may be "challenging" during the early work-up to differentiate between sepsis and cardiogenic shock secondary to myocarditis in febrile patients, but emphasize that a "high index of suspicion is warranted."

Several initial tests should be conducted in the emergency department (ED) for patients with suspected early FM who are hemodynamically stable:   

  • ECG

  • Chest x-ray

  • Complete blood cell count (including differential)

  • Basic metabolic panel

  • Natriuretic peptide

  • Arterial blood gas or venous blood gas

  • Liver function tests

  • Blood cultures (for febrile patients)

  • Serum cardiac troponin

In additional to echocardiography, which plays a "primary role" in the diagnosis and surveillance of myocarditis, cardiac MRI may suggest "functional and morphological features," and gadolinium contrast-enhanced cardiac MRI "affords unique insights into tissue-level pathologies consistent with myocarditis," the authors state.

Initial ED Management

FM in cardiogenic shock and in cardiac arrest should be treated according to the American Heart Association's guideline for advanced cardiac life support, with management "geared toward resuscitation and stabilization," the authors state.

They emphasize that institutions without advanced surgical and medical HF management capabilities, including "expertise in myocardial management," should consider transferring patients directly from the ED to a tertiary referral hospital that can provide advanced circulatory support and transplantation in the event of circulatory failure.

Recommendations for the initial management of FM are listed below:

  • Avoid giving intravenous fluids to hypotensive patients because they can worsen symptoms and hemodynamics in the event of acute heart failure or cardiogenic shock

  • Vasopressor therapy with norepinephrine has been found to be superior to dopamine in the event of acute myocardial infarction, although the effect of its use in FM is "unknown"

  • Use early invasive management to rule out epicardial coronary disease and measure hemodynamics.

  • Endomyocardial biopsy may "reduce the time of end-organ and brain hypoperfusion and decrease time to the specific diagnosis of the cause of FM that may have a specific treatment."

The statement "offers guidance on when to do a biopsy, what to do with the biopsy, and what to do with each diagnosis found by biopsy," Cooper noted.

Ideally, a multidisciplinary shock team can be involved to "determine the most appropriate modality of support and to implement the plan rapidly, before multisystem organ failure begins or worsens."

Hemodynamic support is necessary for initial stabilization, and respiratory support is often necessary to maintain adequate tissue perfusion and end-organ delivery. To that end, mechanical circulatory support (MCS) devices or extracorporeal life support (ECLS) may be required.

Patients without the need for extracorporeal oxygenation can receive percutaneous biventricular assist devices, which have the benefit of eliminating some risks associated with ECLS, as well as the need for an oxygenator, the authors state.

An added advantage is that these devices can provide biventricular unloading, which decreases myocardial wall stress, thus lessening potential exacerbation of injury to a heart already suffering from inflammation.

Following stabilization, the authors recommend that all patients with FM and contractile dysfunction — regardless of the pathogenesis of the disease — be treated with evidence-based neurohormonal antagonist therapy.

Not Your Typical Patients

The capacity of the heart to recover and the treatment trajectory will depend on the cause of FM. For example, in patients with fulminant lymphocytic myocarditis, "the heart will often recover spontaneously with time."

In other immune-mediated FM subtypes, "appropriate immunomodulatory therapy" can help the heart to recover.

Temporary MCS "can offer short-term stability and support of the patient's other organs while the patient awaits cardiac transplantation," which may be necessary, although it is uncommon.

The authors recommend that patients who have recovered from FM should abstain from competitive sports for at least 3 to 6 months, resuming only after a normal exercise tolerance test, ECG, and Holter monitor.

"Patients presenting with FM are not the typical critically ill patients seen in the office or ED," the authors note, because they are "typically younger and healthier," and "present with atypical manifestations of myocardial ischemia and organ system failure."

They add that their statement does not contain "guideline-based recommendations" because current evidence "is not strong enough to reach the rigor required to be classified as guidelines." Rather, "these are considerations for the clinician to review that are based on our expert experience."

Cooper reports receiving a research grant from the NHLBI and is an unpaid board member of the Myocarditis Foundation. The other authors' disclosures are listed on the original paper.

Circulation. Published online January 6, 2020. Article

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