Backgrouds and Objectives : Intracoronary electrocardiogram (IC-ECG) reflects electrical activity of regional myocardium and can be easily measured in the catheterization laboratory during percutaneous coronary interventional (PCI) procedures. Furthermore, it could be used evaluating myocardial viability in patients with acute myocardial infarction (AMI). The aim of this study was to evaluate the usefulness of IC-ECG to predict microvascular integrity and late improvement of left ventricular (LV) function after primary PCI in patients with AMI.
Materials and Method: Total 69 patients (male 49, female 20) who were performed primary PCI using stent implatation had enrolled in this study. After implantation of the stent, IC-ECG was recorded from the tip of a insulated angioplasty guide wire before and after balloon occlusion of infarct related artery. IC-ECG was obtained from inferior and inferolateral wall (inferior wall MI), or apex and apical anteror wall (anterior wall MI). Significant ST segment elevation was defined as further ST segment elevation of ≥ 0.2 mV at 80 msec after J-point. The microvascular integrity of myocardium was evaluated by myocardial contrast echocardiography (MCE) at next day of PCI. After 6 months, all the patients were followed up by echocardiography and measured wall motion score index(WMSI) and ejection fraction(EF).
Results: After coronary occlusion, significant ST elevation was noted in 39 patients (Group A) and there was no significant change in other 30 patients (Group B). MCE showed microvascular perfusion in 34 patients of Group A(87%) and 4 patients of Group B(13%) (p<0.05). From a 6 month follow-up echocardiography, group A revealed lower WMSI(1.22±0.19 vs 1.53±0.46, p<0.05) and higher EF( 56.6±8.1 vs 46.2±10.2, p<0.05) than Group B.
Conclusion: IC-ECG during PCI is a simple and useful method for assessing microvascular integrity of myocardium and predicting long-term improvement of LV function
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