**5. Conclusions and future perspectives**

As present, stress testing, especially by dobutamine infusion, is considered to be useful for detecting residual contractile reserve in DCM. Myocardial contractile reserve is usually detected by echocardiography, but sometimes evaluated by other modalities for accuracy, such as quantitative gated SPECT, cardiac pool scintigraphy, and LV pressure analysis. A lot of previous studies revealed that the presence of residual contractile reserve is associated with a good prognosis and impaired contractile reserve is affected by multiple factors including, but not limited to, exercise intolerance, cardiac sympathetic dysfunction, reduced myocardial blood flow and histopathological changes. In addition, the possibility is suggested that myocardial contractile reserve would predict a reversibility of LV dysfunction after initiation of cardioprotective therapy. Evaluating residual contractile reserve may have key information to predict response to interventional therapy. Therefore, further studies are required in order to detect non-responders with no available future reverse remodeling.

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