Abstract

Objective: To assess the relative influence of contractile reserve and inducible ischaemia on subsequent left ventricular volume changes after myocardial infarction.

Design: Left ventricular end diastolic and end systolic index volumes were calculated prospectively at discharge and at six months in 143 patients referred for early postinfarction dobutamine stress echocardiography. On the basis of their responses to this test, patients were divided into three groups: scar (n = 48; group 1); contractile reserve (n = 36; group 2); inducible ischaemia (n = 59; group 3).

Results: At six months, the left ventricular end diastolic index volume decreased in group 2 (mean (SD), −3.9 (9.4) ml/m²) and increased in both group 1 (+2.8 (10.6) ml/m², p = 0.009 v group 2) and group 3 (+7.5 (11.4) ml/m², p < 0.0001 v group 2). The end systolic index volume decreased in group 2 (−4.9 (7.3) ml/m²) and increased in both group 1 (+1.3 (8.3) ml/m², p = 0.0015 v group 2) and group 3 (+2.8 (8.9) ml/m², p = 0.0002 v group 2). In multivariate analysis, the contractile reserve (hazard ratio 0.19, 95% confidence interval (CI) 0.14 to 0.47), inducible ischaemia (5.86, 95% CI 1.54 to 29.7), and end systolic index volume at discharge (1.04, 95% CI 0.99 to 1.11) were independent predictors of an increase in end diastolic index volume of ⩾ 15 ml/m² at six months.

Conclusions: Contractile reserve and inducible ischaemia, as detected by early dobutamine stress echocardiography, identify patients with differences in long term left ventricular remodelling after acute myocardial infarction.