Myocarditis
This page is for adult patients. For pediatric patients, see: myocarditis (peds)
Background
- Inflammatory cardiomyopathy caused by damage and necrosis of myocytes
- Viral-induced is the most common etiology[1]
- Clinical presentation ranges from smoldering heart failure to fulminant cardiogenic shock or sudden death
- Maintain a high index of suspicion in younger patients without traditional CAD risk factors
Causes
- Infectious agents
- Enterovirus (Coxsackie B) and adenovirus most common
- Influenza A and B
- Hepatitis B
- Beta-hemolytic streptococcus
- Mycoplasma
- Mumps
- CMV
- Toxoplasma
- Chagas (most common cause worldwide)
- Trichinosis
- Sarcoidosis
- Systemic lupus erythematosus
- Diphtheria
- Lyme disease
- COVID-19[2]
- Drugs
Phases
- Acute
- Direct cytotoxicity and focal necrosis from viral, autoimmune, or toxins
- Subacute
- Host's humoral/immune response (viral molecular mimicry and anti-myocyte antibody production) leading to further cell injury
- Chronic
- Diffuse myocardial fibrosis and cardiac dysfunction
Clinical Features
- Typically young patients (20 - 50 years) with few risk factors for CAD
- Chest pain or chest pressure/tightness
- Flu-like symptoms
- Fever, fatigue, myalgia, nausea and vomiting
- Tachycardia (out of proportion to fever)
- Tachypnea
- New onset congestive heart failure, which may include fatigue, orthopnea, or dyspnea on exertion
- Consider this diagnosis in the septic-appearing patient who gets WORSE after receiving IV fluids
- Pediatric patients: See myocarditis (peds)
Differential Diagnosis
Consider other causes of CHF
Chest pain
Critical
- Acute coronary syndromes (ACS)
- Aortic dissection
- Cardiac tamponade
- Coronary artery dissection
- Esophageal perforation (Boerhhaave's syndrome)
- Pulmonary embolism
- Tension pneumothorax
Emergent
- Cholecystitis
- Cocaine-associated chest pain
- Mediastinitis
- Myocardial rupture
- Myocarditis
- Pancreatitis
- Pericarditis
- Pneumothorax
Nonemergent
- Aortic stenosis
- Arthritis
- Asthma exacerbation
- Biliary colic
- Costochondritis
- Esophageal spasm
- Gastroesophageal reflux disease
- Herpes zoster / Postherpetic Neuralgia
- Hypertrophic cardiomyopathy
- Hyperventilation
- Mitral valve prolapse
- Panic attack
- Peptic ulcer disease
- Pleuritis
- Pneumomediastinum
- Pneumonia
- Rib fracture
- Stable angina
- Thoracic outlet syndrome
- Valvular heart disease
- Muscle sprain
- Psychologic / Somatic Chest Pain
- Spinal Root Compression
- Tumor
Evaluation
Diffuse ST elevation in a patient with combined myocarditis and pericarditis.
- ECG needs to be obtained to rule out ischemia. Myocarditis may exhibit the following findings:
- Sinus tachycardia
- Nonspecific ST-T changes
- Low voltages
- Prolonged QTc
- AV block may be present in Lyme disease or Sarcoidosis as the infiltrative process involves the AV node
- Wide QRS, including Left bundle branch block, may be seen
- Note that a normal EKG does not rule out myocarditis
- Elevated troponin or Brain natriuretic peptide
- CXR
- May demonstrate indirect signs such as cardiomegaly, pulmonary edema, or pleural effusion
- Echocardiography
- Decreased LVEF
- Global hypokinesis or regional wall motion abnormalities
- Changes to LV geometry
- Detection of concomitant pericarditis (if present, would then be named myopericarditis)
- Cardiac MRI with contrast
- Noninvasive gold standard for structural-functional changes
- Nuclear Study
- Widespread uptake indicating myocyte necrosis
- Viral titres
- Endomyocardial biopsy (EMB): Invasive gold standard, but rarely used
- Coronary angiography is indicated in selected patients where acute coronary syndrome is suspected
Management
- Acute phase
- Subacute phase
- Studies have not shown efficacy of immunosuppressants for acute myocarditis, unless in specific EMB-proven cases
- Pediatric patients may receive high-dose IVIG
- Chronic phase
- Treatment for CHF symptoms, which may include GDMT meds or diuresis
- Ventricular Assist Devices (VAD)
- Cardiac transplant
Disposition
- If CHF is present, admit to a monitored bed
- If hemodynamically unstable, admit to ICU
Prognosis
- Fulminant myocarditis has best prognosis
- Mortality: 20% 1 yr/ 50% 5 yr
- Children with 70% survival rate at 5 yrs
Complications
See Also
External Links
2024 ACC Expert Consensus on Myocarditis[4]
References
- ↑ Cooper LT Jr. Myocarditis. N Engl J Med. 2009 Apr 9;360(15):1526-38. doi: 10.1056/NEJMra0800028. PMID: 19357408; PMCID: PMC5814110.
- ↑ Mele D, Flamigni F, Rapezzi C, Ferrari R. Myocarditis in COVID-19 patients: current problems. Internal and Emergency Medicine. 2021. doi:10.1007/s11739-021-02635-w
- ↑ Mele D, Flamigni F, Rapezzi C, Ferrari R. Myocarditis in COVID-19 patients: current problems. Internal and Emergency Medicine. 2021. doi:10.1007/s11739-021-02635-w
- ↑ Writing Committee; Drazner MH, Bozkurt B, Cooper LT, Aggarwal NR, Basso C, Bhave NM, Caforio ALP, Ferreira VM, Heidecker B, Kontorovich AR, Martín P, Roth GA, Van Eyk JE. 2024 ACC Expert Consensus Decision Pathway on Strategies and Criteria for the Diagnosis and Management of Myocarditis: A Report of the American College of Cardiology Solution Set Oversight Committee. J Am Coll Cardiol. 2025 Feb 4;85(4):391-431. doi: 10.1016/j.jacc.2024.10.080. Epub 2024 Dec 10. PMID: 39665703.