In the absence of contraindications and when PCI is not available, fibrinolytic therapy is reasonable for patients with STEMI if there is clinical and/or ECG evidence of ongoing ischemia within 12 to 24 hours of symptom onset and a large area of myocardium at risk or hemodynamic instability. (Level of Evidence: C) Class III: Harm 1. Fibrinolytic therapy should not be administered to patients with ST depression except when a true pos- terior (inferobasal) MI is suspected or when associ- ated with ST elevation in lead aVR.10,11,81,312,313 (Level of Evidence: B) 5.1.1. Timing of Fibrinolytic Therapy The benefits of fibrinolytic therapy in patients with ST eleva- tion or bundle-branch block MI are well established, with a time-dependent reduction in both mortality and morbidity rates during the initial 12 hours after symptom onset.81,306 As noted in Section 3.2, even when interhospital trans- port times are short, there may be advantages to the immediate delivery of fibrinolytic therapy versus any delay to primary PCI for patients with STEMI and low bleeding risk who pres- ent within the first 1 to 2 hours of symptom onset.123,321 Benefit from fibrinolytic therapy in patients who present >12 hours after symptom onset has not been established,81,307,309,322,323 although there remains consensus that consideration should be given to administering a fibrinolytic agent in symptom- atic patients presenting >12 hours after symptom onset with STEMI and a large area of myocardium at risk or hemody- namic instability if PCI is unavailable.4,48 5.1.2. Choice of Fibrinolytic Agent Fibrin-specific agents are preferred when available. Adjunc- tive antiplatelet and/or anticoagulant therapies are indicated, regardless of the choice of fibrinolytic agent. Table 4. 