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

Abstract

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).
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.
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-elevation AMI.
Changes produced by DBT in patients with LVEF < 40%, RCS > or = 3, or EDVI > or = 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 > or = 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).
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.