Electrocardiographic Comparison Of Myocardial Salvage Between Primary Coronary Angioplasty And Intravenous Thrombolysis In Acute Myocardial Infarction

Background There is clear evidence that reperfiision therapy improves survival in selected patients with acute myocardial infarction (AMI). Early and effective blood flow through the infarct related vessel is important for limitation of infarct size and preservation of left ventricular function with acute myocardial infarction. Primary coronary angioplasty (P?PICA) may offer advantages in these respects compared with thrombolytic therapy (TT). Electrocardiogram methods can determine the extent of myocardial salvage with different AMI therapies by comparing infarct size predicted by initial ST-changes and infarct size estimated by later quantitative QRS scoring system.Objectives The purpose of this study was to assess the effects of different reperfusion therapies on limitation of myocardial infarct size and to establish the usefulness of ECG scoring system for estimation of myocardial infarct size in acute myocardial infarction. Methods and Results We evaluated the 218 patients with acute myocardial infarction hospitalized at cardiologic unit of No2, Tianjin hospital, from September 1999 to December 2002 (retrospective study). All the patients had typical feature of acute myocardial infarction without confounding factors, such as ventricular hypertrophy, bundle branch block, previous infarction and patients with ventricular paced rhythm and any contraindications of thrombolysis. One hundred patients were assigned to undergo primary coronary angioplasty group and other 118 were selected for thrombolytic therapy. Myocardial salvage and estimated infarct size were obtained by quantitative ECG method. Left ventricular ejection fraction was assessed by echocardiography method before discharge.There was significantly difference in median myocardial salvage percentage between total patients of Primary coronary angioplasty and thrombolytic therapy group (28.42% Vs 15.49%, P=0.007). Global ejection fraction was better in Primary coronary angioplasty group than in thrombolytic therapy group(57 + 10 Vs 52+11, P=0.016). Myocardial salvage was better in patients with inferior myocardial infarction than of anterior myocardial infarction in individual treatment groups (37.74 % Vsl6.76 %, P=0.006 in Primary PICA group) and (18.6% Vs 13.46%, P=0.128 in TT group) There was good correlation between myocardial salvage percentage and ejection fraction (%) in both reperfusion treatment groups ( r = 0.691, p< 0.0001 in Primary PTC A group Vs r - 0.679, p < 0.0001 in TT group, r = 0.708, p < 0.0001 in Total Patients group ). Conclusions In patients with acute myocardial infarction, Primary Coronary Angioplasty results in a smaller infarct size and better preserved myocardial function compared with Thrombolytic therapy. This is probably due to early and optimal blood flow through the infarct-related vessel, as can be accomplished in a very high percentage of patients undergoing primary coronary angioplasty.