The 12-lead ECG and the initiation of thrombolytic therapy for acute myocardial infarction.
Previous work has shown that the ST-segment of acute myocardial infarction (MI) on the admitting electrocardiogram (or vectorcardiogram) is predictive of the final predischarge QRS score (or loss of QRS spatial vector magnitude), in terms of MI size, ejection fraction, acute MI mortality, and prognosis. Patients in the GISSI I randomized multicenter trial were risk stratified by the ECG. The relative risk (RR) of mortality in the group treated with thrombolytic therapy compared to control subjects was as follows: anterior, 0.75; inferior, 0.94; multiple, 0.61; lateral, 1.22; and prior MI 1.03, thus, indicating subsets with no benefit from thrombolysis (RR > or = 1). The RR was also 1.00 in an overlapping group of 3,539 out of 11,712 patients (30%) with ST elevation limited to two or three leads, indicating a final MI size < 10% of the left ventricle. A similar RR was demonstrated in the European Cooperative Group trial of recombinant tissue-type plasminogen activator. This study examines published data from two randomized control trials, ISIS II (n = 17,187) and GISSI II (n = 12,490), for evidence of a similar relationship. The known distribution of MI size, right ventricular infarction, and mortality data in each electrocardiographic trial subset was used to develop a risk predictive model for RR as a function of the initial ST-segment predicted MI size in each location. This further subsetting of the data revealed that 37%, that is, over 10,000 patients, in these two large trials, who did not have a prior MI or evidence of right ventricular infarction, had small MIs.(ABSTRACT TRUNCATED AT 250 WORDS)
Selvester
R H
RH
Memorial Heart Institute, Long Beach, California.
D004562:Electrocardiography; D006801:Humans; D015337:Multicenter Studies as Topic; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000188:drug therapy / Q000401:mortality / Q000473:pathology; D016032:Randomized Controlled Trials as Topic; D012307:Risk Factors; D015912:Thrombolytic Therapy