Relation between infarct artery patency at late angiography after acute myocardial infarction and signal-averaged electrocardiography.

The angiograms of 89 patients were reviewed from the LATE Ancillary Study (randomized trial of recombinant tissue plasminogen activator vs placebo in patients with symptom onset after 6 hours of myocardial infarction) to determine patency of the infarct-related artery (IRA). In the occluded IRA group (n = 35), the incidence of signal-averaged electrocardiographic abnormality (fQRS > 120 ms) was significantly higher (p = 0.04), the filtered QRS duration was significantly longer (p = 0.007), and the V40 was significantly shorter (p = 0.02), compared with the patent IRA group (n = 54).