A monitoring device for a patient for predicting a cardiovascular anomaly and a method for operating a monitoring device is provided. Furthermore, an implantable electrotherapy device, such as an implantable cardiac pacemaker, an implantable cardioverter, or an implantable defibrillator, having a monitoring device are also provided. In an embodiment, the monitoring device acquires a value change of a hemodynamic parameter, which occurs as a result of a detected value change of a state parameter, for example, as a result of an activation or deactivation of a cardiac resynchronization therapy. By suitable evaluation of the value change of the hemodynamic parameter, the monitoring device can output an evaluation result signal which is indicative of an imminence of a cardiovascular anomaly, such as a cardiac decompensation, long beforehand and with high specificity.