Does ST segment monitoring on a single ECG lead accurately recognize reperfusion within 60 minutes of therapy in patients with acute myocardial infarction?
ST segment monitoring with a >= 50% decrease from peak levels provides a highly sensitive and specific non-invasive method for assessing reperfusion within 60 minutes of acute myocardial infarction therapy.
OBJECTIVES: This study was designed to test the hypothesis that monitoring the ST segment on a single electrocardiographic (ECG) lead reflecting activity in the infarct zone provides sensitive and specific recognition of reperfusion within 60 min of initiation of therapy in acute myocardial infarction. BACKGROUND: Infarct-related arteries that fail to recanalize early may benefit from immediate rescue angioplasty. Hence, detection of reperfusion has important practical clinical implications. METHODS: Of 41 patients with acute myocardial infarction who had ambulatory ECG (Holter) monitors placed, 38 had adequate ST segment monitoring for 3 h; 35 of the 38 were treated with thrombolytic agents and 3 with primary angioplasty. All patients underwent early coronary angiography and were classified into two groups: Group P (22 patients) had angiographic patency (Thrombolysis in Myocardial Infarction TIMI grade 2 or 3 flow), the Group O (16 patients) had persistent occlusion (TIMI grade 0 or 1 flow) of the infarct-related vessel at 60 min from initiation of therapy. The initial ST segment level was defined as the first ST segment level recorded; the peak ST segment level was defined as the highest ST segment level measured during the 1st 60 min. To assess the optimal ST segment recovery criteria for reperfusion, the presence or absence of a > or = 75%, > or = 50% and > or = 25% decrement from initial and peak ST segment levels, sampled and analyzed at 2.5-, 5-, 10-, 15-and 20-min intervals, was correlated with patency of the infarct-related artery at 60 min. RESULTS: ST segment recovery of > or = 50% reduction from peak ST segment levels with sampling rates at or = 50% reduction in ST segment levels within 60 min was less sensitive. Prediction of coronary reperfusion within 60 min of therapy on the basis of a > or = 75% decrement from peak ST segment levels was less sensitive, and the use of a > or = 25% decrement was less specific. CONCLUSIONS: ST segment monitoring of a single lead reflecting the infarct zone provides a reliable method for assessing reperfusion within 60 min of acute myocardial infarction. Optimal criteria for ECG reperfusion include a > or = 50% decrease from peak ST segment levels, with ST segment measurements recorded continuously or at least every 10 min.
Fernandez et al. (Fri,) studied this question.