Background: The relationship between admission left ventricular (LV) volumes, regional contractility and persistent ST elevation in first anterior ST elevation myocardial infarction (STEMI) with evolution of LV volumes at 12 months remains inconclusive. Thus possible differences among patients with reverse dilatation (RD), stationary dilatation (SD) or progressive dilatation (PD) at 12 months based on left ventricle end-systolic volume (LVESV) index changes were investigated.
Patients and methods: ECG and echocardiographic features of 394 1-year survivors of anterior STEMI were analyzed at admission, 6 and 12 months in those with RD (≥15% reduction of LVESV index, at 12 months n=141), SD (<15% reduction or increase, n=123) or PD (≥15% increase, n=130). Long-term outcome was also evaluated.
Results: Admission LVESV values in tertiles and incidence of moderate-severe mitral regurgitation were similar in three groups. In patients with RD, LVESV decreased at 6 months (P<0.001) and further at 12 months (P=0.003), whereas in PD, it increased at 6 months (P<0.001) and further at 12 months (P=0.016). Contractility score in PD was higher on admission (P=0.050) than in the other groups, but it involved the same segments. At 12 months, it improved in each of the six most affected in RD (P<0.001) and SD (P=0.025-0.001) but not in PD group (P=0.452-1.00). Persistent ST elevation at 24 h and peak troponin I were the only independent predictors for RD (odds ratio: 0.900, 95% confidence interval: 0.840-0.905, P=0.003; 0.996, 0.986-0.994, P<0.001) and PD (1.143, 1.001-1.304, P=0.048; 1.004, 1.002-1.006, P<0.001), respectively. During an 8-year follow-up, 77 (19.5%) patients died and although the total mortality was comparable in the three groups, cardiac death or hospitalization for heart failure was higher in the PD (16/130, 14%) than in the other two groups (14/250, 5.6%, P=0.014).
Conclusion: Admission normal or enlarged LV volumes may evolve towards RD, SD or PD at 12 months following first anterior STEMI mainly depending in part on infarct size. Importantly, relevant changes occur at not only 6 months but also between 6 and 12 months.