Effect of early intravenous rt-PA on infarct size estimated from serum enzyme activity: results from the TEAHAT Study.
In 319 patients who participated in a double-blind trial to evaluate the effect of early rt-PA administration compared to placebo in suspected acute myocardial infarction, infarct size was assessed from analyses of serum activity of lactate dehydrogenase isoenzyme 1 (LD 1). Treatment was always started less than 3 h after the onset of symptoms, with one-third of the patients' treatment being initiated outside the hospital. The maximum activity of LD 1 was reduced by 32%, from 13.3 mu kat l-1 in placebo to 9.0 mu kat l-1 in rt-PA treated patients (P = 0.001). A reduction in LD-1 activity after rt-PA treatment was restricted to patients with ST-elevation in the initial electrocardiogram, and was more pronounced in patients with previous ischaemic heart disease, above median age, and in those with a shorter delay in initiation of treatment. We conclude that very early intravenous treatment with rt-PA limits indirect signs of infarct size. The effect appears to be restricted to patients with ST-segment elevation in their initial electrocardiogram.
Risenfors
M
M
Department of Medicine I, Sahlgrenska Hospital, Göteborg, Sweden.
Hartford
M
M
Dellborg
M
M
Luepker
R
R
Hjalmarsson
A
A
Swedberg
K
K
Holmberg
S
S
Herlitz
J
J
D000553:Ambulatory Care; D003402:Creatine Kinase / Q000378:metabolism; D004311:Double-Blind Method; D004562:Electrocardiography; D005260:Female; D006801:Humans; D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis / Q000188:drug therapy* / Q000201:enzymology*; D015912:Thrombolytic Therapy; D010959:Tissue Plasminogen Activator / Q000627:therapeutic use*
D007527:Isoenzymes; D007770:L-Lactate Dehydrogenase; D003402:Creatine Kinase; D010959:Tissue Plasminogen Activator