[Prediction of improvement of left ventricular systolic function by dobutamine echocardiography after recent myocardial infarction]. / Prédiction de l'amélioration de la fonction systolique ventriculaire gauche par échographie à la dobutamine après infarctus du myocarde récent.

ABSTRACT

Left ventricular ejection fraction is a major prognostic factor of ischaemic heart disease. In the early phase of myocardial infarction, part of the myocardium may be stunned and responsible for marked segmental wall dysfunction which is potentially reversible. The authors studied the potential of low dose dobutamine echocardiography to predict secondary improvement of left ventricular systolic function in 21 patients with recent inaugural myocardial infarction without primary angioplasty. All patients were treated and the investigation was carried out up to 20 micrograms/Kg/min of dobutamine without unwanted side-effects or myocardial ischaemia. The detection of viability by this method was associated with improved wall motion of the affected segments in 74% of cases, most of which had benefited from myocardial revascularisation at control echocardiography performed 8 weeks later. If 4 or more segments were estimated to be viable initially, the left ventricular ejection fraction improved to a value comparable to that obtained at a dosage of 20 micrograms/Kg/min of dobutamine. On the other hand, there was no secondary improvement in 76% of segments estimated to be non-viable whether or not they had been revascularised. The sensitivity, specificity, positive and negative predictive values of low dose dobutamine echocardiography for prediction of myocardial recovery after recent infarction were respectively 71, 79, 74 and 76%. The results of this investigation show prognostic value and could be an aid to the decision concerning revascularisation of patients not having undergone primary angioplasty.