Predischarge low‐dose dobutamine test and prediction of left ventricular function at 1 year in patients with a first anterior myocardial infarction

Background: It is unclear whether spontaneous improvement in contractility following acute myocardial infarction (AMI) is related to severity of predischarge systolic dysfunction and can be predicted by isotopic ventriculography with a low‐dose dobutamine test (DBT). Hypothesis: Spontaneous improvement in contractility would be similar in patients with more preserved and those with depressed ventricular function, and a DBT test could predict it. Methods: Left ventricular ejection fraction (LVEF), regional contractility score (RCS), and left ventricular end‐diastolic volume index (EDVI) at predischarge, during DBT, and at 1 year were analyzed in 43 patients with a first anterior ST‐ele‐vation AMI. Results: Changes produced by DBT in patients with LVEF <40%, RCS >3, or EDVI >70 ml/m2 were smaller than in those observed at 1 year (LVEF: 30 ± 5‐35 ± 7%, p < 0.001, vs. 39 ± 10%, p = 0.005; RCS: 4.9 ± 1.4‐4.6 ± 2.0, NS, vs. 3.4 ± 2.0, p<0.02; EDVI: 92 ± 14‐86 ± 22, NS, vs. 78 ± 23 ml/m2, p < 0.03). In contrast, in patients with EF > 40%, RCS < 3 or EDVI < 70 ml/m2, changes with DBT tended to be greater than those observed at 1 year (LVEF: 52 ± 8‐57 ± 11%, p< 0.004 vs. 55 ± 11%, p< 0.04); RCS: 1.1 ± 0.9‐0.8 ± 0.8, NS, vs. 1.1 ± 1.1, NS; and EDVI: 51 ± 9‐47 ± 11, p < 0.005, vs. 54 ± 13 ml/m2, NS). Conclusions: Among patients with a first anterior AMI, spontaneous improvement in contractility at 1 year was greatest in those with a more depressed ventricular function or a dilated ventricle, but its magnitude was underestimated by a predischarge DBT test.