Prognostic Value of Low-Dose Dobutamine Echocardiography in Patients With Idiopathic Dilated Cardiomyopathy

Abstract

Dobutamine echocardiography is widely used for the evaluation of myocardial contractile reserve. The purpose of the study was to determine the prognostic value of low-dose dobutamine echocardiography in patients with idiopathic dilated cardiomyopathy (IDCM). The study group consisted of 77 consecutive patients with recently diagnosed IDCM (mean [+/- SD] age, 49 +/- 9 years; men, 82%) and left ventricular (LV) ejection fractions of < 40%. Two-dimensional and Doppler echocardiographic variables were measured before and after the infusion of dobutamine at the rate of 10 microg/kg/min for 5 min. During a mean follow-up period of 63 +/- 7 months (range, 49 to 75 months) 30 patients (39%) died and five patients (6%) underwent successful heart transplantations. Using multivariate regression analysis, the only significant factors related to fatal outcome or the need for cardiac transplantation were the following: (1) LV end-systolic volume of > 150 mL after low-dose dobutamine infusion (odds ratio [OR], 2.2; confidence interval [CI], 1.2 to 4.1; p = 0.011); (2) no decrease of LV end-diastolic volume after dobutamine infusion (OR, 1.9; CI, 1.1 to 3.4; p = 0.031); (3) atrial fibrillation (OR, 2.7; CI, 1.4 to 5.3; p = 0.003); and (4) male gender (OR, 2.6; CI, 1.2 to 5.5; p = 0.017). A scoring system was proposed with one point assigned for each of the above-mentioned factors. The mortality rates for total scores of 0, 1, 2, 3, and 4 were 0%, 19%, 48%, 83%, and 100%, respectively. The response of the LV to low-dose dobutamine infusion adds clinically valuable prognostic information to the evaluation of the patient with IDCM.