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).

A new regimen for heparin use in acute coronary syndromes.

BACKGROUND: Recent trials have demonstrated an association between high activated partial thromboplastin time (aPTT) and bleeding, intracranial hemorrhage, reinfarction, and death in patients with acute coronary syndromes treated with heparin. Of all the factors that affect aPTT in patients treated with heparin, body weight is most strongly correlated. METHODS: We compared the efficacy of 2 weight-adjusted heparin regimens (groups 2 and 3) and the standard (group 1) non-weight-adjusted 5000-U intravenous bolus/1000 U/hr infusion to achieve an aPTT between 45 and 70 seconds in a nonrandomized prospective cohort of 80 patients admitted with unstable angina and non-ST elevation myocardial infarction. RESULTS: Patients treated with the lower dose of weight-adjusted heparin (60 U/kg intravenous bolus, maximum of 4000 U; 12 U/kg/hr, maximum 900 U/kg), group 3, were more often within the target range for aPTT at 6 hours (34% vs 5% vs 0%) and required fewer heparin infusion changes (1.0 +/- 1.0 vs 1.9 +/- 1.0 vs 2.0 +/- 0.9) within the first 24 hours compared with the other regimens. Patients in groups 1 and 2 were overwhelmingly above target range at 6 hours (95% and 84%, respectively, compared with 48% in group 3). CONCLUSIONS: Traditional heparin dosing regimens result in marked initial overanticoagulation in patients with acute coronary syndromes, which may place these patients at higher risk of adverse outcomes. A lower dose weight-adjusted heparin regimen is superior in achieving early aPTTs within the target range and reducing the need for infusion changes over the ensuing 24 hours.

Unusually long inflation times during percutaneous transluminal coronary angioplasty.

Unusually prolonged balloon inflations (PBI) during percutaneous transluminal coronary angioplasty (PTCA) have been utilized in 26 consecutive patients to establish adequate coronary perfusion after shorter inflation times resulted in severe residual stenosis (N = 15), early arterial closure (N = 5), or extensive dissection (N = 6). Inflations lasted 1.5 to 15 min and 23/27 stenoses were successfully dilated. The average reduction in stenosis was 67% (90%-33%). Chest pain occurred in 34% vs. 7% (P less than 0.01), and ST changes occurred during 66% vs. 57% (NS) of PBI vs. short inflations. Four patients required coronary artery bypass surgery in spite of PBI, but none suffered an infarction. Electrocardiograms were unchanged in 22 patients and showed nonspecific ST-T wave changes in four. Cardiac enzymes obtained in nine patients failed to reveal a significant increase in serum concentration. We conclude that PBI is well tolerated and can successfully dilate lesions not responding to short inflations.