The present invention provides an in vitro method for obtaining data useful for diagnosing a cardiomyopathy in a human subject, wherein the method comprises using, as an indicator, the expression levels, obtained from a biological sample isolated from the human subject, preferably a plasma sample, of one or more of the following miRNAs miR-721 and/or miR-155); and obtaining a result of the method by comparing the expression levels of said one or more miRNAs with a reference value or with the expression levels of a control, indicator of the absence of cardiomyopathy.