April 12, 2011 by dailybolusoflr
Thrombolytics in Acute MI
· ST segment elevation of 1 mm or more in two or more anatomically contiguous leads limb leads or 2mm or more in two or more anatomically contiguous precordial leads
· New or presumed new LBBB
Typical time frame is under 12 hours after symptom onset, although patients with stuttering symptoms can be considered up to 24 hours. The best outcomes are in patients who have symptoms under 6 hours.
For patients at non-PCI centers, and in whom transfer to a PCI center for intervention would take LONGER than 90 minutes, the goal should be to administer tPA within 30 minutes of presentation.
The most common finding on EKG after reperfusion is ventricular ectopy. You may also see short episodes on non-sustained VT. Sustained episodes should be treated with anti-dysrhythmics. There is no consensus supporting treatment of non-sustained VT or ectopy in this setting.
· After the infusion of tPA, successful reperfusion is demonstration by resolution of chest pain and by a decrease in STE by at least 50%. This is typically seen by 90 minutes in patients with successful intervention.
· In patients with unsuccessful reperfusion, “rescue PCI” can be considered, where patients are transferred to a PCI center after administration of tPA with a failed outcome.
· tPA can also be considered prior to transfer of a patient for planned PCI and this is termed “facilitated PCI.” This is more controversial and protocols have considered full dose and half dose tPA before transfer for PCI- some studies show higher morbidity and mortality in these patients.
Linda Regan, MD FACEP
Program Director, Emergency Medicine Residency
Johns Hopkins Medical Institutions