Abnormal contractile responses during dobutamine stress echocardiography in patients with idiopathic dilated cardiomyopathy

BACKGROUND: In chronic heart failure augmented wall stress leads to increased energy demand. Supply, however, may be reduced due to coronary vasoconstriction and endothelial dysfunction. This might lead to a mismatch between demand and supply. In the present study we further explored the effect of increased demand during dobutamine stress echocardiography. METHODS AND RESULTS: Sixteen patients with idiopathic dilated cardiomyopathy (mean age 44+/-13 years, New York Heart Association class II-III, mean left ventricular ejection fraction 0.27+/-0.10) underwent dobutamine stress echocardiography (5-40 microg/min per kg bodyweight+atropine if required). Wall motion and thickening was assessed in 16 segments using a four-point scale. Eleven patients (69%) showed regions with worsening of wall motion or a biphasic response during dobutamine infusion. Of the remaining five patients one patient did not show any wall motion changes and one patient showed a partial improvement while only in three patients wall motion improvement in the whole heart was found. CONCLUSION: A majority of patients with idiopathic dilated cardiomyopathy showed decreased wall motion during increased demand, i.e. ischemia-like myocardial contractile responses during dobutamine stress echocardiography. These findings further support the concept that an energy mismatch between demand and supply might play a pathophysiological role in idiopathic dilated cardiomyopathy.