LEFT-VENTRICULAR REMODELING IN THE YEAR AFTER MYOCARDIAL-INFARCTION -AN ECHOCARDIOGRAPHIC, HEMODYNAMIC, AND RADIONUCLIDE ANGIOGRAPHIC STUDY

Background: The factors that influence infarct expansion early after m yocardial infarction have been identified; however, there is less info rmation about late-phase left ventricular enlargement. This study was designed to identify the clinical, haemodynamic, echocardiographic, an d radionuclide angiographic criteria that predict the progress of left ventricular dilation after discharge for a first-anterior myocardial infarction. Methods: Sixty-seven patients with first Q-wave acute ante rior myocardial infarction not treated with thrombolytic agents underw ent baseline echocardiographic, haemodynamic, and radionuclide angiogr aphic evaluation 4-7 days after the onset of symptoms. The echocardiog raphic and radionuclide evaluations were repeated after 1 year in the 55 patients who completed the follow-up. By multivariate stepwise line ar regression analysis, left ventricular end-diastolic volume after 1 year and change from baseline were modelled as a function of baseline left ventricular end-diastolic volume and other potential predictors. Results: A model including left ventricular end-diastolic pressure, gl obal wall motion score, baseline left ventricular end-diastolic volume , and a Thrombolysis in Myocardial Infarction (TIMI) score of 0-1 was able to predict 84% of the left ventricular end-diastolic volume at th e follow-up; a TIMI score of G-1, the transverse end-diastolic diamete r, global wall motion score, and the number of coronary vessels with 7 0% stenosis accounted for 81% of the variation in left ventricular end -diastolic volume from baseline, while the transverse end-diastolic di ameter was inversely related to this parameter. Conclusions: The resul ts of this study demonstrate that after an anterior myocardial infarct ion, the patency of the infarct-related artery is the major determinan t of late left ventricular dilation, while left ventricular end-diasto lic pressure influences early left ventricular dilation and baseline e nd-diastolic volume. Therefore, to improve left ventricular remodellin g, it appears necessary to increase the patency of the infarct-related artery and improve the diastolic loading of the left ventricle at an early stage in the infarction. The inverse relationship between baseli ne left ventricular transverse diameter and the change in left ventric ular volume after discharge indicates that the higher the baseline lef t ventricular volume, the less it changed during the follow-up. The gl obal wall motion score appears to be a non-invasive parameter that is useful for identifying patients with a high risk of progressive left v entricular dilation.