Heterogeneity of left ventricular remodeling after acute myocardial infarction: Results of the Gruppo Italiano per lo Studio della Sopravvivenza nell'Infarto Miocardico-3 Echo Substudy

Background Left ventricular (LV) remodeling after acute myocardial infarcti on has still to be clarified in the thrombolytic era. Methods To evaluate timing and the magnitude and pattern of postinfarct LV remodeling, a subset of 614 patients enrolled in the Gruppo Italiano per to Studio della Sopravvivenza nell'Infarto Miocardico-3 Echo Substudy underwe nt serial 2-dimensional echocardiograms at 24 to 48 hours from symptom onse t (S1), at hospital discharge (S2), at 6 weeks (S3), and at 6 months (S4) a fter acute myocardial infarction. Results During the study period the end-diastolic volume index (EDVi) incre ased (P < .001) and wall motion abnormalities (%WMA) decreased (P < .001), whereas election fraction (EF) remained unchanged. Nineteen percent of pati ents showed a > 20% increase in EDVi at S2 compared with S1 (severe early d ilation), and 16% of patients showed a > 20% dilation at S4 compared with S 2 (severe late dilation). Independent predictors of severe in-hospital LV d ilation were relatively small EDVi (odds ratio [OR] 0.961, 95% confidence i nterval [Cl] 0.947-0.974, P = .0001) and relatively large %WMA (OR 1.030, 9 5% CI 1.013-1.048, P = .0005). Similarly, smaller predischarge EDVi (OR 0.9 75, 95% Cl 0.963-0.987, P = .0001), greater %WMA (OR 1.026, 95% Cl 1.008-1. 045, P = .0042), and moderate to severe mitral regurgitation (OR 2.261, 95% Cl 1.03 1-4.958, P = 0.0417) independently predicted severe late dilation. Importantly, 92% of the patients with severe early dilation did not have f urther dilation at S4, and 91% of patients with severe late dilation did no t have in-hospital dilation. EF was unchanged over time in patients with ea rly dilation, whereas it significantly decreased in those with late dilatio n. Conclusions Although in-hospital LV enlargement is not predictive of subseq uent dilation and dysfunction, late remodeling is associated with progressi ve deterioration of global ventricular function over time: patients with ex tensive %WMA and not significantly enlarged ventricular volume before disch arge are at higher risk for progressive dilation and dysfunction.