The present invention relates to a medical device, in particular to an implantable medical device, comprising at least one implantable or non-implantable hemodynamic sensor configured for detecting hemodynamic cardiac signals, a controller configured for processing and analyzing the detected cardiac hemodynamic signals or signals derived from the detected cardiac hemodynamic signals by applying to said signals a Teager Energy Operator (TEO). The controller further comprises at least one algorithm configured to determine the need for a defibrillation operation by taking into account the at least one output hemodynamic signal. The present invention also provides a method and software for detecting or treating a ventricular fibrillation episode by taking into account cardiac hemodynamic signals.
