provide as little as first aid and early defibrillation. Others employ highly trained paramedics with sophisticated technology and advanced protocols. Paramedic services are capable of providing oxygen, IV access, sublingual nitroglycerine, morphine, and aspirin. Some advanced paramedic systems can also perform 12-lead ECGs. If a STEMI is recognized the paramedic may be able to contact the local PCI hospital and alert the emergency room physician, and staff of the suspected AMI. Some Paramedic services are capable of providing thrombolytic therapy in the prehospital setting, allowing reperfusion of the myocardium. With primary PCI emerging as the preferred therapy for ST-segment elevation myocardial infarction, EMS can play a key role in reducing door-to-balloon intervals (the time from presentation to a hospital ER to the restoration of coronary artery blood flow) by performing a 12-lead ECG in the field and using this information to triage the patient to the most appropriate medical facility. In addition, the 12-lead ECG can be transmitted to the receiving hospital, which enables time saving decisions to be made prior to the arrival of the patient. This may include a "cardiac alert" or "STEMI alert" that calls in off duty personnel in areas where the cardiac cath lab is not staffed 24 hours a day. Even in the absence of a formal alerting program, prehospital 12-lead ECGs are independently associated with reduced door to treatment intervals in the emergency department. Initial diagnostic approach In patients with symptoms typical of myocardial ischemia an electrocardiogram must be immediately obtained - e.g., within 10 minutes from first contact with medical or paramedical personnel, including prehospital setting; the electrocardiographic findings will guide the subsequent management. Patients with elevation of the ST segment (or presumed new left bundle branch block) are treated based on guidelines for ST elevation myocardial infarction (STEMI) and must undergo reperfusion therapy as soon as possible. Serum cardiac biomarkers are routinely obtained and their elevation is necessary for confirming diagnosis of myocardial infarction; however, reperfusion must not be delayed by waiting for the results. Patients without the above findings are initially classified with non ST elevation acute coronary syndrome, and subsequent cardiac biomarker results will differentiate between true non ST elevation myocardial infarction (NSTEMI) and unstable angina. Relief of angina Relief of the pain of angina is of paramount importance, not only for humane reasons but because the pain is associated with sympathetic activation that causes vasoconstriction and increases the