Inclusion Criteria:

1. The patient must be ≥18 years and ≤75 of age.
2. Prolonged, continuous (≥ 30 min) chest pain despite nitrate and: (1) ST-segment elevation ≥ at least 2 leads, with reciprocal ST-segment elevation ≥ 0.05mv and precordial leads ST-segment elevation ≥ 0.01mv, or (2) newly developed left bundle branch block
3. Symptoms ≥ 30 min and ≤12 hours
4. The patient has consented to participate and has authorized the collection and release of his medical information by signing the "Patient Informed Consent Form"
5. All lesions requiring interventions in one or more native coronary arteries are amendable for implantation of one or more Cypher® Sirolimus-Eluting Coronary Stent System or Endeavor® Zotarolimus-Eluting Coronary Stent
6. The patient or guardian is willing and able to cooperate with study procedures and required follow up visits.

Exclusion Criteria:

1. Pregnant and breast-feeding female and female of childbearing potential, who possibly plan to become pregnant any time after enrollment into this study.
2. Systemic (intravenous) Sirolimus use within 12 months.
3. Patients with hypersensitivity or allergies to one of the drugs or components indicated in the Instructions for Use of either stents.
4. History of bleeding diathesis or known coagulopathy (including heparin-induced thrombocytopenia), or will refuse blood transfusions.
5. Gastrointestinal or genitourinary bleeding within the prior 3 months, or major surgery within 2 months.
6. Current platelet count <100 x 10^9cells/L or Hgb <10 g/dL.
7. Fibrinolytic therapy for current MI treatment
8. Previous coronary intervention on target vessel or post-CABG vessel disease
9. Transplant patients
10. Patients with EF<25%
11. Patients with cardiogenic shock; with a life expectancy shorter than 12 months
12. Severe kidney dysfunction: Creatinine level ≥2.0mg/dL or dependence on dialysis.
13. Severe hepatic dysfunction (AST and ALT ≥ 3 times upper normal reference values).
14. The patient is currently, and during the CREST-MI Study, participating in another investigational device or drug study that clinically interferes with the CREST-MI study endpoints; or requires coronary angiography or other coronary artery imaging procedures. The patient may only be enrolled in the CREST-MI Study once.
15. Severe tortuous or calcified vessel; stent can not or has difficulty to go through; blood vessel diameter is smaller than the minimum stent diameter available; patients unsuitable for stent implantation.