Key result
The presence of initial Q waves at presentation predicted failure to achieve 50% ST recovery (OR 5.08; 95% CI 1.29-20.01; P=0.02) in patients with a first acute myocardial infarction.
Why the study?
Does the presence of initial Q waves at presentation predict slower ST segment recovery in patients with a first acute myocardial infarction treated with streptokinase?
Cohort (n=144)
Does the presence of initial Q waves at presentation predict slower ST segment recovery in patients with a first acute myocardial infarction treated with streptokinase?
Odds Ratio: 5.08 (95% CI 1.29–20.01)
Absolute Event Rate: 80% vs 95%
p-value: p=0.02
The presence of initial Q waves at presentation in acute myocardial infarction predicts slower and less complete ST segment recovery despite early infarct artery patency, indicating reduced microvascular reperfusion.
Initial Q waves may signal impaired microvascular reperfusion after streptokinase; hypothesis-generating for targeted strategies in first AMI.
BACKGROUND: The presence of Q waves at presentation with a first acute myocardial infarction reflects a more advanced stage of the infarction process. When infarct-related artery patency (Thrombolysis in Myocardial Infarction 2 or 3 flow) is restored, resolution of ST segment elevation indicating successful myocyte reperfusion may differ according to how far the infarction process has progressed. METHODS AND RESULTS: In 144 patients with a first acute myocardial infarction treated with streptokinase in the first Hirulog Early Reperfusion Occlusion trial, information was obtained from continuous ST segment monitoring, the presenting electrocardiogram and early angiography performed at a median time of 99 min after the commencement of streptokinase (interquartile range 89-108 min). We determined how many patients had 50% ST recovery within 120 min and in how many cases it was sustained over 4h. In the 109 patients with patent infarct-related arteries, 50% ST recovery occurred in 95% of patients without vs 80% of those with initial Q waves (P=0.03), and sustained ST recovery occurred in 67% of patients without vs 47% of those with initial Q waves (P=0.03). On multivariate analysis including the time from symptom onset to streptokinase therapy, the presence of Q waves at presentation was the only predictor of failure to achieve 50% ST recovery (odds ratio 5.08, 95% confidence interval 1.29-20.01, P=0.02). TIMI 2 flow, as opposed to TIMI 3 flow, was the only predictor of failure to achieve stable ST recovery (odds ratio 2.63, 95% confidence interval 1.15-5.88,P =0.02). CONCLUSION: The presence of initial Q waves predicts slower and less complete ST recovery, reflecting reduced myocyte reperfusion, even in those with early infarct artery patency. These patients may be targeted for new therapeutic strategies to improve microvascular reperfusion.
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Cheuk-Kit Wong (2002) conducted a cohort in Acute myocardial infarction (n=144). Presence of initial Q waves vs. Absence of initial Q waves was evaluated on 50% ST recovery within 120 min (OR 5.08, 95% CI 1.29-20.01, p=0.02). The presence of initial Q waves at presentation predicted failure to achieve 50% ST recovery (OR 5.08; 95% CI 1.29-20.01; P=0.02) in patients with a first acute myocardial infarction.
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