Syndrome differentiation and treatment
The therapeutic principles of viral myocarditis include strengthening body resistance to eliminate pathogenic factors, clearing away heat and toxin, activating yang and resolving phlegm, promoting blood circulation to remove blood stasis, warming and activating the heart yang, supplementing qi and nourishing yin.

1. Pathogenic heat invading the heart 
Main symptoms and signs: Prolonged fever, or lingering low fever, nasal obstruction with discharge, sore throat, cough, or abdominal pain and diarrhea, chest distress, short breath, listlessness, hypodynamia, red tongue with thin fur, thready and rapid or knotted pulse.
Therapeutic methods: Clearing away heat, removing toxin, strengthening body resistance and nourishing the heart.

2. Obstruction of chest yang     
Main symptoms and signs: Chest distress with pain, palpitation, restlessness, cough, sticky sputum, nausea, vomiting, pale tongue with turbid and greasy fur, soft pulse.

3. Stagnation of the heart blood
Main symptoms and signs: Stabbing chest pain, palpitation, chest distress, cyanotic lips and dim complexion, purplish tongue or with ecchymosis, unsmooth and knotted pulse.
Therapeutic methods: Activating blood circulation to remove blood stasis and calming the mind.

4. Deficiency of the heart yang
Main symptoms and signs: Palpitation, dizziness, stuffy chest, listlessness, spontaneous sweating, cold body and limbs, cyanotic lips and nails, weak breathing, pale tongue with whitish fur, thready and rapid or extremely weak pulse.  
Therapeutic method: Warming and activating the heart yang.

5. Deficiency of both qi and yin  
Main symptoms and signs: Palpitation, restlessness worsened by moving, chest distress, short breath, dizziness, hypodynamia, dysphoria with fever, poor  sleep, spontaneous sweating, night sweat, pale and enlarged tongue with a little or no fur, thready and rapid or knotted pulse.
Therapeutic methods: Supplementing qi, nourishing yin and calming the mind.