What are the differences in diagnostic findings, pathophysiology, and treatment approaches for myocarditis (inflammation of the myocardium) and pericarditis (inflammation of the pericardium)?

From the Guidelines

Myocarditis and pericarditis are distinct inflammatory conditions with different diagnostic findings, ideologies, and treatments, and the most recent guidelines recommend a tailored approach to each condition based on the latest evidence. Myocarditis involves inflammation of the heart muscle (myocardium), while pericarditis affects the pericardium, the fibrous sac surrounding the heart. Diagnostically, myocarditis typically presents with elevated troponin levels, ECG changes including ST-segment elevation or T-wave inversions, and cardiac MRI showing late gadolinium enhancement, as noted in the 2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR guideline 1. In contrast, pericarditis shows diffuse ST-segment elevation on ECG, PR depression, and often a pericardial friction rub on examination, with echocardiography demonstrating pericardial effusion.

The treatment for myocarditis focuses on supportive care, heart failure management with ACE inhibitors like lisinopril (10-40 mg daily) or beta-blockers such as metoprolol (12.5-200 mg daily), and in severe cases, immunosuppression with corticosteroids, as recommended by the European Society of Cardiology (ESC) guidelines 1. Pericarditis treatment centers on anti-inflammatory therapy with NSAIDs like ibuprofen (600-800 mg three times daily for 1-2 weeks) or colchicine (0.5-0.6 mg twice daily for 3 months in first episodes, 6 months in recurrences), with corticosteroids reserved for refractory cases. Both conditions require monitoring for complications, including heart failure and arrhythmias in myocarditis, and cardiac tamponade or constrictive pericarditis in pericarditis cases.

Some key differences between the two conditions include:

• Diagnostic findings: myocarditis typically presents with elevated troponin levels and cardiac MRI showing late gadolinium enhancement, while pericarditis shows diffuse ST-segment elevation on ECG and pericardial effusion on echocardiography.
• Treatment approach: myocarditis treatment focuses on supportive care and heart failure management, while pericarditis treatment centers on anti-inflammatory therapy.
• Complications: myocarditis is associated with heart failure and arrhythmias, while pericarditis is associated with cardiac tamponade and constrictive pericarditis.

The most recent and highest quality study, the 2021 AHA/ACC/ASE/CHEST/SAEM/SCCT/SCMR guideline, provides the best evidence for the diagnosis and treatment of myocarditis and pericarditis 1. This guideline recommends a tailored approach to each condition, taking into account the latest evidence and expert opinion. By following this guideline, clinicians can provide optimal care for patients with myocarditis and pericarditis, reducing morbidity, mortality, and improving quality of life.

From the Research

Diagnostic Findings

• Myocarditis and pericarditis have distinct diagnostic findings, with pericarditis typically presenting with acute sharp, retrosternal, and pleuritic chest pain 2.
• Myocarditis, on the other hand, has highly variable clinical manifestations, making it essential to have a high level of suspicion in the early stage of disease to facilitate diagnosis 2, 3.
• Diagnostic methods for myocarditis include noninvasive cardiac magnetic resonance imaging and invasive techniques such as endomyocardial biopsy 3.
• Focal echobright, defined as myocardial brightness in the left ventricle regions, is a sensitive indicator for acute myopericarditis in young adults, with a sensitivity of 95% and specificity of 93% 4.
• Pericardial effusion is also a common finding in pericarditis, with a specificity of 81% and sensitivity of 65% 4.

Ideologies

• Myocarditis is an inflammatory disease of the cardiac muscle caused by various infectious and noninfectious conditions, including viral, bacterial, and autoimmune etiologies 2, 3.
• Pericarditis also has several underlying causes, including viral, bacterial, and autoimmune etiologies 2.
• The etiology of myocarditis is broad and can be infectious, autoimmune, or toxin-induced, making it essential to consider various causes when diagnosing and treating the condition 3.

Treatments

• The mainstays of pericarditis treatment are nonsteroidal anti-inflammatory drugs and colchicine, with glucocorticoids or other immunosuppressive drugs used for refractory cases and relapse 2.
• The treatment of myocarditis includes nonspecific treatment aimed at complications such as heart failure and arrhythmia, as well as specific treatment aimed at underlying causes 2, 3.
• Novel approaches to treating myocarditis are being explored, including the use of immunosuppressive drugs and other therapies tailored to the specific etiology of the condition 3.