3.  Etiological Agents Causing Myocarditis
  Viral (Most Common)  
 Adenovirus  
 Coxsackie virus/Enterovirus   
Cytomegalovirus   
Parvovirus B19   
Hepatitis C virus  
 Influenza   
Human immunodeficiency virus   
Herpes virus  
 Epstein-Barr virus   
Mixed infections    

4. Bacterial   
Mycobacterial species   
Chlamydia pneumoniae  
 Streptococcal species   
Mycoplasma pneumoniae   
Treponema pallidum  
Fungal   
Aspergillus   
Candida  
 Coccidioides   
Cryptococcus   
Histoplasma   
Protozoal   Trypanosoma cruzi   
Parasitic   Schistosomiasis   Larva migrans   

5. Toxins   
Anthracyclines   
Cocaine   
Hypersensitivity   
Clozapine   
Sulfonamides   
Cephalosporins   
Penicillins   
ricyclic antidepressants   
Autoimmune Activation
  Smallpox vaccination  
 Giant cell myocarditis  
Churg-Strauss syndrome   
Sjögren syndrome
 Inflammatory bowel disease   
Celiac disease  
 Sarcoidosis   
Systemic lupus erythematosus   
Takayasu arteritis   
Wegener granulomatosis

6.     Expanded Criteria for Diagnosis of Myocarditis
Suspicious for myocarditis = 2 positive categoriesCompatible with myocarditis = 3 positive categories
High probability of being myocarditis = all 4 categories positive(Any matching feature in category = positive for category)  
Category I: Clinical Symptoms   
Clinical heart failure   
Fever  
 Viral prodrome  
 Fatigue
 Dyspnea on exertion   
Chest pain   
Palpitations  
 Presyncope or syncope    

7. Category II: Evidence of Cardiac Structural/Functional Perturbation in the Absence of Regional Coronary Ischemia  
 Echocardiography evidence   
Regional wall motion abnormalities  
 Cardiac dilation   
Regional cardiac hypertrophy   
Troponin release   High sensitivity (>0.1 ng/ml)   
Positive indium-111 antimyosin scintigraphy   and   Normal coronary angiography or   Absence of reversible ischemia by coronary distribution on perfusion scan

8. Category III: Cardiac Magnetic Resonance Imaging   I
ncreased myocardial T2 signal on inversion recovery sequence  
 Delayed contrast enhancement following gadolinium-DTPA infusion   
Category IV: Myocardial Biopsy—Pathological or Molecular Analysis   
Pathology findings compatible with Dallas criteria   
Presence of viral genome by polymerase chain reaction or in situ hybridization

9. Diagnostic Modality Sensitivity Range Specificity Range
Comparison of Efficacy of Various Diagnostic Modalities for Myocarditis
Diagnostic Modality Sensitivity Range Specificity Range
ECG changes (e.g., AV block, Q, ST changes) 47% ?
Troponin (lower threshold of >0.1 mg/ml) 34%-53% 89%-94%
CK-MB 6% ?
Antibodies to virus or myosin 25%-32% 40%
Indium-111 antimyosin scintigraphy 85%-91% 34%-53%
Echocardiography (ventricular dysfunction) 69% ?
Cardiac magnetic resonance imaging 86% 95%
Myocardial biopsy (Dallas criteria of pathology) 35%-50% 78%-89%
Myocardial biopsy (viral genome by PCR) 38%-65% 80%-100%
? = indeterminant or poor; AV = atrioventricular; CK-MB = cytosine kinase isoenzyme; ECG = electrocardiogram; PCR = polymerase chain reaction.