Recent data indicate that the beneficial haemodynamic effects of IA are related to removal of negative inotropic cardiac antibodies. Detection of cardio-depressant antibodies in the plasma of DCM patients, before IA, effectively predicts acute and prolonged haemodynamic improvement during IA. A further study clearly disclosed that the cardio depressant antibodies belong to the IG-3 subclass [38]. The removal of antibodies of the IgG-3 subclass accordingly represents an essential mechanism in IA therapy of DCM.