Myocardial contractile reserve on dobutamine echocardiography predicts late spontaneous improvement in cardiac function in patients with recent onset idiopathic dilated cardiomyopathy.

OBJECTIVES: The purpose of this study was to determine whether identification of contractile reserve with dobutamine would predict recovery of myocardial function during follow-up in patients with recent onset idiopathic dilated cardiomyopathy (IDC).
BACKGROUND: The prognosis of patients presenting with new onset IDC is variable and difficult to predict.
METHODS: Twenty-two patients (17 men, 5 women, 46 +/- 14 years) with recently diagnosed IDC (4 +/- 3 months) underwent dobutamine echocardiography. Left ventricular ejection fraction (LVEF) and LV sphericity before and at peak dobutamine infusion (30 +/- 11 microg/kg/min) were determined. A follow-up echocardiographic assessment was done at 6 +/- 4 months.
RESULTS: The LVEF on dobutamine was directly related to baseline LV mass expressed as g/ml (Pearson r = 0.65, p = 0.0003). Baseline variables that were significantly predictive of follow-up LVEF were deceleration time (r = 0.69, p = 0.0006), wall motion score index (WMSI) (r = -0.63, p = 0.002), LV mass (r = 0.56, p = 0.008) and LVEF on dobutamine (r = 0.84, p = 0.0001). When either deceleration time or WMSI or LV mass was entered into a regression equation to predict follow-up LVEF, the LVEF on dobutamine added significantly to predictive power. However, if LVEF on dobutamine was entered first, none of the other three variables added significantly to prediction. Baseline LV sphericity at end diastole (ED) (r = 0.13, p = 0.6) did not correlate with follow-up LV sphericity in ED, whereas LV sphericity in ED on dobutamine (ED [r = 0.70, p = 0.0004]) correlated with LV sphericity in ED on follow up.
CONCLUSIONS: This study demonstrates that dobutamine-induced improvement in baseline LVEF and LV sphericity identifies patients with IDC who exhibit substantial improvement in LV function and geometry over time.