Quantitative assessment of acute myocardial infarction size. Impact of early mechanical recanalization of infarct related artery]

The aim of investigation: 1) to determine the diagnostic value of QRS score and LV echocardiography in assessment of the size of myocardial infarction in acute stage, 2) to establish the impact of infarct related artery recanalization on myocardial infarction size.In order to investigate whether infarct size could be estimated by QRS scoring system soon after reperfusion we evaluated QRS score obtained serially before and twice after reperfusion, and the echocardiographic global EF in 57 patients with acute myocardial infarction who underwent successful mechanical recanalization of infarct related artery. Coronary flow in infarct related artery was evaluated by the Thrombolysis in Myocardial Infarction trial (TIMI) criteria. QRS scores were calculated according to the method of Wagner (37 criteria and 29 points). The electrocardiographic ejection fractions (EFECG) were calculated according to Roubin method, and the global echocardiographic ejection fractions (EFECHO) were calculated according to Simpson method. All patients were divided into 3 groups according to the quality of myocardial reperfusion expressed as intensity in change of electrocardiographic phases at the time of infarct related artery recanalization (1 gr.--the change of ECG phases > or = 2; 2 gr.--the change of ECG phases through 1; and 3 gr.--with no changes of ECG stages). All patients had an effective infarct-related artery recanalization expressed as 2 or 3 TIMI grade.A low and insignificant correlation was observed between EFECG and EFECHO for patients with anterior myocardial infarction (r = 0.35) and for patients with posterior myocardial infarction (r = 0.12). The EFECG had a tendency to be lower in patients with worse myocardial reperfusion (from 59.06 +/- 6.12 in 1 gr. to 50.93 +/- 10.87 in 3 gr). At this time the EFECHO was almost the same in all groups of patients. Additionally, the EFECHO was significantly lower than EFEKG in all groups of patients (p = 0.000017-0.001). The QRS score had general tendency to increase after infarct-related artery recanalization, however the most evident increase was obtained in 1 gr. of patients with rapid change of ECG stages. A significant correlation (r = 0.87 for patients with anterior myocardial infarction and r = 0.85 for patients with posterior myocardial infarction) was observed between QRS scores obtained after infarct related artery recanalization and that obtained after 10-12 days. In conclusion, QRS score and EFEKG better than EFECHO reflects the myocardial infarction size in acute stage. Increasing of the myocardial infarction size after infarct-related artery recanalization is connected with reperfusional injury more expressed in patients with more effective myocardial reperfusion.