9 Hours of Chest Pain and Deep Q-waves: Is it too late for Thrombolytics? (Time Window for Reperfusion; Acuteness on the ECG)

Conclusion: An invasive strategy based on coronary stenting with adjunctive use ofabciximab reduces infarct size in patients with acute STEMI without persistent symptomspresenting 12 to 48 hours after symptom onset.This is a section on "Acuteness" that I wrote in a Chapter on Reperfusion therapy that I wrote with Bill Brady in Critical Decisions in Emergency and Acute Care Electrocardiography.  I have updated it here.Here are a couple posts that demonstrate the issue of acuteness.Acuteness—when is it too late for reperfusion?  In deciding on reperfusion, particularly on fibrinolytic therapy, it is important to assess the amount of viable injured myocardium at risk of infarction.  This is traditionally done by assessing time since pain onset, and randomized trials of fibrinolytics found no significant advantage if pain duration was greater than 12 hours.[12, 32, 49]  However, time since pain onset is a crude way of assessing amount of infarcted (irreversible), vs. ischemic (viable, salvageable), myocardium.  Often, occlusion is incomplete, or collateral circulation maintains the viability of ischemic myocardium, or there is ischemic preconditioning, and myocardium that is fully salvageable may have pain duration of days.  Fortunately, the ECG is a better indicator of salvageable myocardium than pain duration.              High ECG “acuteness” is associated with significant...
Source: Dr. Smith's ECG Blog - Category: Cardiology Authors: Source Type: blogs