#431 Myocarditis and Pericarditis

March 18, 2024 | By Adam Barelski

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Master myocarditis and prevail over pericarditis!

Join us as we review the diagnosis and treatment of pericarditis, myocarditis, peri-myocarditis, myo-pericarditis…and everything in between! We are joined by our esteemed guest, Dr. Vivek Kulkarni (@VivekKulkarniMD), a clinical cardiologist and assistant program director for the Cardiovascular Disease Fellowship at Cooper University Health Care, who helps us get to the heart of the matter! 

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Show Segments

• Intro, disclaimer
• A case of pericarditis
• Diagnosing pericarditis
• The difference between pericarditis, myocarditis, myopericarditis, and perimyocarditis
• Etiologies of pericarditis and initial testing recommendations
• Treatment of acute uncomplicated pericarditis
• Using colchicine to prevent recurrent pericarditis
• Patient counseling after diagnosing pericarditis
• A case of myocarditis
• Interpreting elevated troponin levels
• Distinguishing between myocardial infarction and myocardial injury
• Diagnostic testing for suspected myocarditis
• When to pursue cardiac MRI and endomyocardial biopsy
• The spectrum of myocarditis presentations
• Fulminant myocarditis
• Common etiologies of myocarditis
• Immune checkpoint inhibitor myocarditis
• Myocarditis from mRNA vaccines and from SARS-CoV-2 infection
• Management of patients with myocarditis
• Activity restrictions for patients with myocarditis
• Outro

Pericarditis and Myocarditis Pearls

1. Positional chest pain should increase clinical suspicion for pericarditis.
2. All patients with suspected pericarditis should receive a prompt transthoracic echocardiogram (TTE).
3. Rapid fluid accumulation in a pericardial effusion can lead to tamponade at a much smaller volume than gradual fluid accumulation.
4. Treatment of choice for most cases of uncomplicated pericarditis should include high-dose non-steroidal anti-inflammatory drugs (NSAIDs)—along with colchicine to prevent recurrent pericarditis.
5. Myocarditis has a broad spectrum of clinical presentations, including chest pain, constitutional symptoms, heart failure, and arrhythmias.
6. Myocarditis is associated with elevated troponins but typically without the dynamic rise and fall of troponin levels seen in acute coronary syndromes.
7. The diagnostic test of choice for most acute myocarditis cases is a cardiac MRI, typically after ischemic evaluation and TTE is performed.
8. Cases of fulminant “crash and burn” myocarditis should receive an endomyocardial biopsy for rapid diagnosis and initiation of disease-specific treatment.
9. Immune checkpoint inhibitor myocarditis is a serious and increasingly recognized clinical entity in patients undergoing cancer treatment.
10.  Patients with a diagnosis of myopericarditis should be appropriately counseled on activity/exercise restriction until myocardial inflammation has resolved.

Myocarditis and Pericarditis – Notes 

Pericarditis

How do patients with pericarditis present? 

Commonly, patients with pericarditis will present with chest pain. Dr. Kulkarni recommends keeping a broad differential diagnosis when patients come in with chest symptoms, including non-cardiac conditions (e.g. pulmonary embolism, pneumonia, and GI diagnoses). Pain related to pericarditis is often much worse when lying back, which is specific to pericarditis, and can help increase clinical suspicion in Dr. Kulkarni’s experience. Patients may not volunteer this information initially, so taking a thorough history is important to clarify your leading diagnostic considerations (Xanthopoulos 2017).

On physical exam, the pericardial friction rub is specific to pericarditis, but the inflammation has to be quite extensive to hear it, and Dr. Kulkarni says that it can be difficult to hear in real world settings. He also recommends an attentive JVP exam as well, including looking for Kussmaul’s sign (an increase in JVP with inspiration), which can be seen in pericardial disease (Mansoor 2015).

Testing in pericarditis 

Most of the time Dr. Kulkarni finds that the clinical diagnosis can be made based on history and physical. There are classic ECG findings, although often in clinical practice the ECG changes are non-specific. The ECG findings that most support the diagnosis of pericarditis are diffuse ST elevations and PR depressions. ST elevations in pericarditis are different from those in acute coronary syndromes (e.g. ST-elevation myocardial infarction, STEMI). In STEMI, the ST elevations are regional, corresponding with an anatomical distribution from a coronary artery, and there should be reciprocal depressions in other leads. In pericarditis, the ST elevations are global, do not correspond with a specific anatomic territory, and do not have associated reciprocal ST depressions in other leads (Marinella 1998).

Elevated serum inflammatory markers are often seen in cases of pericarditis, although these are not specific for the diagnosis.

Pericarditis often occurs after a preceding viral syndrome, which may be elicited by history. It is often not necessary to pursue additional etiologic testing in Dr. Kulkarni’s experience if there is a clear inciting viral infection (expert opinion). If there is no clear preceding viral trigger, he recommends considering additional testing. Other situations that might warrant additional testing include when a patient develops recurrent pericarditis, in immunocompromised patients, in patients with known cancer or rheumatologic disease, or in patients traveling from areas with endemic diseases that can cause pericarditis. In many parts of the world, tuberculous pericarditis is the most common cause of pericarditis. Trypanosomiasis, borreliosis, and other infectious diseases can also affect the pericardium. HIV testing should be considered. Dr. Kulkarni recommends considering patient risk factors to help guide testing (Adler 2015).

Other common causes of pericarditis include recent cardiac surgery or electrophysiology procedures, such as ablations. Dr. Kulkarni notes that many of these patients will have some subclinical inflammation of the pericardium after surgery, but it only needs to be treated in patients with symptoms. Pericarditis treatment is, generally speaking, driven a lot by symptoms.

Patients with pericarditis or in whom you are suspecting pericarditis should have evaluation with transthoracic echocardiography (TTE). The patient may not need to be hospitalized if TTE can be performed rapidly in the outpatient setting, unless they have significant symptoms or there is a significant pericardial effusion on imaging. In the most extreme cases, effusions can accumulate rapidly and lead to pericardial tamponade. When an effusion develops rapidly, even relatively small amounts of fluid can cause elevated intra-pericardial pressures and tamponade physiology, compared to effusions that develop gradually (Klein 2013).

In one article, there needed to be approximately 300 ml of pericardial effusion to cause an enlarged cardiac silhouette on chest X-ray (Larazos 2021). However, a patient may develop tamponade with a lower volume of fluid (150-200 ml) in the setting of rapid accumulation (Jensen 2017).

Management of pericarditis 

The mainstay of treatment for pericarditis includes either high-dose non-steroidal anti-inflammatory drugs (NSAIDs) or high-dose aspirin. Dr. Kulkarni recommends high-dose NSAIDs for most patients, since they are relatively well tolerated and effective. Dosing regimens may include ibuprofen 600-800mg TID or aspirin 750-1000mg TID for 1-3 weeks (Chiabrando 2020). Initial therapy is usually combined with colchicine, which is mainly used to prevent recurrent pericarditis. Colchicine is typically dosed at 0.5mg once or twice daily for 3-6 months (Imazio 2015).

Most people who develop uncomplicated pericarditis will improve in 1-3 weeks with treatment. Recurrent pericarditis may occur in a subset of patients, and this is mainly a symptomatic problem where patients’ symptoms do not resolve as they taper off of treatment. Patients with very chronic pericarditis and pericardial inflammation are at risk for developing pericardial constriction (constrictive pericarditis) (Adler 2015).

Steroids are not first-line therapy in uncomplicated pericarditis without other indications. Patients are at higher risk for recurrent pericarditis when treated with corticosteroids compared with first-line agents (Farand 2010). Dr. Kulkarni also notes that there is a historical concern about rupture of the myocardium in patients with post-MI pericarditis, although this may be less clinically important in the modern revascularization era.

During therapy for pericarditis, Dr. Kulkarni tells patients to avoid heavy physical exertion while they are on NSAIDs and while they continue to have symptoms. 

Myocarditis

Common presentations of myocarditis

Myocarditis can have several different clinical presentations, including chest pain, febrile illness, arrhythmias, elevated troponin levels, heart failure, cardiac arrest, and cardiogenic shock (Al-Akchar 2023). As a result, it is under-recognized and under-diagnosed (Sagar 2011). It requires a high degree of clinical suspicion and often requires ruling out other, more common, diagnoses like myocardial ischemia. Dr. Kulkarni emphasizes that generalized symptoms such as malaise, fevers, and subacute chest discomfort may raise clinical suspicion of myocarditis as they are less typical of ischemia. However, these patients are typically diagnosed after excluding more common cardiac syndromes. 

Elevated troponins suggest ongoing myocardial injury, but they are not specific for myocarditis. Serial troponins may be useful to distinguish between a dynamic rise and fall as would be seen in acute myocardial ischemia or infarction vs. elevated by flat troponins as would be seen in causes of acute or chronic myocardial injury (Thygesen 2018). Patients with myocarditis often receive an ischemic evaluation to ensure there is no active coronary disease (Martens 2023).

Myocarditis workup

Dr. Kulkarni emphasizes that initial testing for patients presenting with myocarditis include TTE and cardiac catheterization. The next test of choice in stable patients with myocarditis would be cardiac MRI (Martens 2023). Cardiac MRI is very good for imaging the myocardium, characterizing the tissue, quantifying the ejection fraction, and specifically looking for myocardial inflammation.

According to Dr. Kulkarni, endomyocardial biopsy is typically reserved for a few specific clinical scenarios: (1) in cases where the data doesn’t add up and there is still diagnostic uncertainty, and (2) when patients present with fulminant myocarditis. Fulminant myocarditis is acute myocarditis in hemodynamically or electrically unstable patients, or patients with acute HF, LV dysfunction, and/or rhythm disorders (Seferović 2021). The goal of endomyocardial biopsy is early recognition and treatment of specific subtypes of myocarditis that may improve with appropriate therapy; these entities commonly include eosinophilic myocarditis, giant cell myocarditis, and lymphocytic myocarditis. Dr. Kulkarni describes these as “crash and burn” fulminant cases which require immediate treatment. There is a small but significant risk of biopsy, often quoted around 1% risk of perforation of the ventricle (ranging in studies between 0%-6.9%) with a 0%-0.07% risk of death  (Seferović 2021). 

Common causes of myocarditis include viral infections, immune-mediated or rheumatologic causes, granulomatous diseases (e.g. sarcoidosis), giant cell myocarditis, eosinophilic myocarditis, medication related myocarditis (e.g. immune-checkpoint inhibitors), and vaccine-associated myocarditis, among others. A few specific causes of myocarditis have unique features. Lyme carditis, which is more common in endemic areas, is characterized by conduction system disease and heart block. It is worth considering, especially in the right geographical area at the right time of year (Robinson 2015).

Recently with the advent of mRNA vaccines for COVID-19, there has been a lot of discussion about the risks of myocarditis after immunization for COVID-19. Evidence indicates that mRNA COVID-19 vaccination is associated with a small increased risk of myocarditis, especially in young males (Goddard 2022). There is also a risk of myocarditis from COVID infection (Patone 2022). Dr. Kulkarni still recommends people get vaccinated, though he has noticed that the specific risk-benefit analysis has become less controversial now that most people have either natural and/or vaccine-derived immunity from COVID-19.

Management of myocarditis

Dr. Kulkarni notes that there are not great randomized controlled trials to guide treatment recommendations for acute myocarditis. His rule of thumb is that the sicker the patient is, the more aggressively empiric immunosuppression is started. 

Certain types of myocarditis (especially fulminant myocarditis) respond well to immunosuppression and pulse-dose steroids, including eosinophilic myocarditis and immune-checkpoint inhibitor (ICI) myocarditis. Giant cell myocarditis may respond to immunosuppression, often requiring a combination of corticosteroids and anti-T lymphocyte immunosuppressive therapy. Patients with fulminant myocarditis or advanced heart failure should be transferred to a tertiary care facility with capability for mechanical circulatory support and preferably a cardiac transplant center (Ammirati 2020).

Patients with LV dysfunction and heart failure should receive standard guideline-directed medical therapy. Patients with arrhythmias may require implantable cardioverter-defibrillators (ICDs).

Dr. Kulkarni recommends checking troponins as an easy way to monitor for ongoing myocardial inflammation in the management of patients with myocarditis. He also will consider serial cardiac MRIs in certain patients to monitor the progression or resolution of disease. Patients diagnosed with myocarditis should be counseled on exercise restriction. Typically these patients should restrict exercise for 3–6 months to promote resolution of inflammation, depending on the clinical severity, LV function, and extent of inflammation on cardiac MRI (Pelliccia 2019). Once again, Dr. Kulkarni emphasizes that these decisions are not based on strong evidence and must be individualized for patients. 

Goal

Listeners will recognize and manage the spectrum of myopericarditis.

Learning objectives

After listening to this episode listeners will…  

1. Create an illness script for pericarditis, myocarditis, and myo-pericarditis 
2. List common etiologies of myocarditis and identify potential fulminant causes 
3. Describe the most common causes of acute pericarditis 
4. Develop a management plan for acute pericarditis, including how to prevent recurrent pericarditis 
5. Counsel patients on activity restrictions after an episode of myopericarditis

Disclosures

Dr. Kulkarni reports no relevant financial disclosures. The Curbsiders report no relevant financial disclosures. 

Citation

Barelski AM, Kulkarni V, Williams PN, Jyang, E, Witt, L, Watto MF. “#431 Myocarditis and Pericarditis”. The Curbsiders Internal Medicine Podcast. thecurbsiders.com/category/curbsiders-podcast Final publishing date March 18, 2024.