Early Definition of Treatment Outcomes After Reperfusion Therapy for Myocardial Infarction

Abstract

Aims. Early definition of treatment outcomes, including coronary patency and infarct size, after reperfusion therapy for myocardial infarction (MI) is desirable to identify patients requiring further intervention. Methods and Results. Patients receiving reperfusion therapy for a first MI had continuous 12-lead ST segment monitoring to document reperfusion and ischaemia time. Infarct size was measured by 12-lead QRS score and radionuclide scintigraphy ( 201 Tl single-photon emission computed tomography, SPECT) at 1 week, and left ventricular function by echocardiography at 1 week and 1 month. Resolution of ST elevation accurately detected TIMI 2 or 3 reperfusion (predictive accuracy 93%) in 55 patients undergoing immediate angioplasty, but ST recovery was delayed (17±14 min) after angiographic reperfusion. A multivariate model, including risk region and ischaemia time, accurately predicted MI size ( R 2=0.80, P<0.00001) in these patients. The same model, prospectively applied on Day 1 to 154 patients receiving thrombolytic therapy, accurately predicted MI size, measured by QRS score ( R 2=0.88, P<0.0000001) and 201 Tl SPECT ( R 2=0.75, P<0.000001) at 1 week for individual patients. Regional myocardial wall motion at 1 month was directly correlated with MI size predicted by the model on Day 1 ( r=0.73, P<0.0001). Conclusions. Use of ST segment monitoring during reperfusion therapy facilitates early prediction of treatment outcomes, including coronary reperfusion, infarct size and ventricular function.