1. Viral (Coxsackie B, influenza, HIV, enteroviruses)
2. Idiopathic (about 50% of cases)
3. Familial/genetic
4. Alcohol
5. Chemotherapeutic agents (most commonly daunorubicin and doxarubacin)
6. Selenium deficiency
7. Thyroid disease
8. Tachycardia mediated
9. Peripartum