What is the difference between pericarditis and myocarditis?

From the Guidelines

Pericarditis and myocarditis are distinct heart conditions that require different treatment approaches, with pericarditis typically managed with NSAIDs and colchicine, and myocarditis focusing on managing heart failure symptoms and avoiding physical exertion during the acute phase. Pericarditis is inflammation of the pericardium, the thin sac-like membrane surrounding the heart, while myocarditis is inflammation of the myocardium, the heart muscle itself. Pericarditis typically presents with sharp, stabbing chest pain that worsens when lying down and improves when sitting up and leaning forward, often with a characteristic friction rub on auscultation and diffuse ST-segment elevation on ECG 1.

Key Differences and Treatment Approaches

• Pericarditis:
  • Presents with sharp, stabbing chest pain
  • Characteristic friction rub on auscultation
  • Diffuse ST-segment elevation on ECG
  • Treatment: NSAIDs like ibuprofen (600-800mg three times daily) or aspirin (650-975mg every 4-6 hours) for 1-2 weeks, with colchicine (0.5mg twice daily for patients >70kg or 0.5mg once daily for patients <70kg) added to prevent recurrence 1
• Myocarditis:
  • Presents with more vague symptoms like fatigue, shortness of breath, and sometimes chest discomfort
  • May cause arrhythmias, heart failure symptoms, and elevated cardiac enzymes
  • ECG changes are variable and less specific than in pericarditis
  • Treatment: focuses on managing heart failure symptoms, with medications like ACE inhibitors, beta-blockers, and diuretics as needed, while avoiding physical exertion during the acute phase 1

Recent Guidelines and Recommendations

The most recent guidelines from 2022 recommend that patients with suspected myocarditis should undergo initial testing consisting of an ECG, measurement of cTn, and an echocardiogram, with cardiology consultation recommended for those with a rising cTn and/or ECG or echocardiographic abnormalities concerning for myocarditis 1. For pericarditis, hospitalization is recommended for diagnosis and monitoring of patients with myocardial involvement and differential diagnosis, especially with acute coronary syndromes, with empirical anti-inflammatory therapies like aspirin or NSAIDs usually prescribed to control chest pain 1.

Diagnostic Approaches

Diagnostic approaches for both conditions include:

• ECG to show diffuse ST-segment elevation in pericarditis or variable changes in myocarditis
• Echocardiography to assess for pericardial effusion or myocardial dysfunction
• Cardiac MRI (CMR) with late gadolinium enhancement imaging to show characteristic changes of acute myopericarditis
• Blood tests for markers of inflammation and myocardial lesions

Given the potential for serious complications, particularly with myocarditis, it is crucial to prioritize early diagnosis and appropriate treatment to minimize morbidity, mortality, and improve quality of life. The choice between pericarditis and myocarditis treatment should be guided by the most recent and highest-quality evidence, with a focus on reducing inflammation, managing symptoms, and preventing long-term cardiac damage 1.

From the Research

Pericarditis vs Myocarditis

• Pericarditis is the inflammation of the pericardium, the membranous sac surrounding the heart, and is a common cause of nonischemic chest pain, accounting for up to 5% of emergency department visits for nonischemic chest pain in North America and Western Europe 2.
• Myocarditis, on the other hand, is an inflammatory disease of the cardiac muscle, caused by a variety of infectious and noninfectious conditions, and mainly affects young adults (median age 30-45 years), with men more than women 3.
• The clinical manifestations of myocarditis are highly variable, making it essential to have a high level of suspicion in the early stage of disease to facilitate diagnosis 3.
• Pericarditis is typically diagnosed with the presence of 2 or more of the following: sharp, pleuritic chest pain, new widespread electrocardiographic ST-segment elevation and PR depression, a new or increased pericardial effusion, or a pericardial friction rub 2.
• Treatment of acute pericarditis involves the use of high-dose nonsteroidal anti-inflammatory drugs (NSAIDs), with doses tapered once chest pain has resolved and C-reactive protein level has normalized, typically over several weeks, and a 3-month course of colchicine to relieve symptoms and reduce the risk of recurrence 2.
• Colchicine has been shown to be effective in reducing the number of pericarditis recurrences in patients with recurrent pericarditis or acute pericarditis, with moderate quality evidence that colchicine reduces episodes of pericarditis in people with recurrent pericarditis over 18 months follow-up 4.
• Beta-blockers have also been found to be useful in controlling symptoms in patients with pericarditis, with a lower frequency of symptoms persistence at 3 weeks and a trend towards a reduction of recurrences at 18 months 5.
• A study comparing colchicine monotherapy to NSAID monotherapy or combination therapy for the prevention of recurrent pericarditis in patients with heart failure with reduced ejection fraction and/or coronary artery disease found no difference in the primary outcome between groups, but a prospective, randomized trial is needed to further elucidate the efficacy of colchicine monotherapy 6.

Key Differences

• Pericarditis is characterized by inflammation of the pericardium, while myocarditis is characterized by inflammation of the cardiac muscle.
• Pericarditis typically presents with sharp, pleuritic chest pain, while myocarditis has highly variable clinical manifestations.
• Treatment of pericarditis involves NSAIDs and colchicine, while treatment of myocarditis includes nonspecific treatment aimed at complications such as heart failure and arrhythmia, as well as specific treatment aimed at underlying causes.

Similarities

• Both pericarditis and myocarditis can be caused by infectious and noninfectious conditions.
• Both conditions can have serious complications, such as constrictive pericarditis and heart failure.
• Both conditions require prompt diagnosis and treatment to prevent long-term damage and improve outcomes.